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Monthly Discharge Data for World
Annotations for Monthly Discharge Data for World (excluding former Soviet Union) Rivers derived from submissions to UNESCO and other sources Version 1.3, July 2001 Byron A. Bodo [email protected] Toronto, Canada Disclaimer Users assume responsibility for errors in the river and stream discharge data, associated metadata [river names, gauge names, drainage areas, and geographic coordinates], and the annotations contained herein. No doubt errors and discrepancies remain in the metadata and discharge records. Anyone data set users who uncover further errors and other discrepancies are invited to report them to NCAR. 2 Preface River and stream discharge data have many, often very technical, uses. My personal needs for global discharge data stem from the occasional need to rough out regional surface water budgets, estimate runoff at locations where data are not readily available, evaluate hydrologic and other environmental data for obscure geographic locales reported in scientific and technical reports, and other similarly informal, quick calculations. For most purposes, a good global hydrological atlas in digital format with maps and statistical summary data on rainfall, surface runoff, etc. would suffice. One does not yet exist, so the next best thing is to derive results directly from readily available compilations of precipitation and surface discharge records. Although somewhat limited in temporal and spatial coverage, the companion data set is a good introductory collection of 970 records for exploring surface global runoff. Temporal coverage of the original UNESCO source records has been extended with additional data from independent sources for more than 200 gauges. This set excludes data from countries of the former Soviet Union [FSU]. Data for these can be had from several sources including NCAR and R-Arcticnet. Why Annotate I began keeping notes on discrepancies in the IHD, WMO and other small discharge data sets in 1995. I welcomed the RIVDIS (RIV herein) compilation released in 1998, but immediately began finding discrepancies with RIV vis-à-vis other data sets. These notes grew sporadically since then as time permitted. They concern all the discharge data series for non-FSU countries in the main UNESCO source files that could be presently checked. Some remain unchecked because no alternate data have been available. There should be no need to keep extensive notes, but most international stream discharge, precipitation, and other environmental data sets that I have encountered have been riddled with errata. Regrettably, data quality control and quality assurance [QC/QA] seem to be alien concepts to compilers (i.e., humans) of these data sets. The present notes make it much easier for users (myself included) to know what was done, why it was done, what remains uncertain, and to use the data with a reasonable measure of confidence. For openly published and allegedly vetted data files, the UNESCO compilations of monthly river discharge data contain ubiquitous errors in the gauge metadata and the discharge series, as do many alternative data sources not originating directly from national agencies. If the UNESCO metadata and discharge records could be readily replaced with the latest versions from the national source agencies, the annotations would be minimal. Except for US discharge records and scattered gauges in other countries for which recent data are now available over the internet, this is presently impossible. For most non-US sites, the only means of 3 evaluating data is to apply statistical procedures and cross-reference alternate versions. Decisions to choose a particular version over another, or to alter questionable data are generally not definitive; hence, the need for documentation. How to Use This Document This report was not intended to be read from beginning to end. It is intended to be used as a look-up reference when concerns arise about particular discharge records. The first three sections are recommended reading for anyone intending to use of the companion data set, or using the main source data sets. This report is intended for on-screen viewing. Clicking on the page number in the Table of Contents of the MS Word doc file [not the pdf version] will jump to the section of interest. If using the MS Word version, use “Normal” view and turn on “Gridlines” in the “Table” menu. A few math symbols may not be rendered correctly in the pdf version created by NCAR. Check the MS Word version if anything appears suspect in the pdf file. Printing is not recommended as sections, tables and graphics will sprawl across page breaks. The internet addresses [URLs] given herein are not live. URLs have to be copied and pasted into your internet browser. Distribution Package Files in the distribution package are listed below. The spreadsheet inventory file unq_cat.xls has additional information including basic summary statistics, a cross listing of gauge codes that includes GRDC site code numbers, a table of ISO country codes, and tables of alternate drainage areas given in different sources. The spreadsheet is useful for quick sorting and selection of sites by country, continent, drainage area, etc.. File name Format Contents readme.unq ascii description of distribution files & formats unq.cat ascii site catalogue unq_cat.xls MS Excel 8 site catalogue with summary statistics and additional information un.q ascii monthly discharge data un_notes.doc MS Word 6 notes — this document 4 Updates: July 2001 • • Chao Phraya @ Khai Chira Prawat/Nakhon Sawan (C.2) gained 11 yrs the site name is changed to Khai Chira Prawat as in Thailand’s gauge inventory • several UK gauges gained some recent 1996-1999 data • • Thames River @ Kingston data, widely available in UNESCO and other sources, are actually “naturalized” pseudo discharges a short record Thames (gauged) @ Kingston containing monitored discharges has been added and the differences between “naturalized” and “gauged” data are discussed • two Bolivian gauges gained some additional data • • • • notes explain why data for China’s Huai @ Bengbu are so unusual added notes for Blue Nile @ nr Lake Tana added notes for Peruvian gauges clarified notes on St. Lawrence River @ Ogdensburg and St. Lawrence @ Cornwall/Massena • numerous, mostly minor, metadata fixes Updates: March 2001 • • • • • • • • updated & revised data for most US sites; revision of section 16 on US data, including clarification of discharge through the lower Mississippi-Atchafalaya system updated & revised data at many non-US gauges deletion of one redundant record replacement of one discontinued record with a superior alternate addition of one alternate record clarification & update of the main Amazon River gauge [Amazon @ Obidos] revisions to section on Argentina, particularly clarification of gauge records for Sali Dulce and Parana; restoration of record Parana @ Corrientes many metadata fixes Table. Gauge record (mainly non-US) updates; March & June 2001 ID # River Gauge 9141 Bani Douna ML AF 9212 9214 Tigris (Dijlah) Euphrates (Al Furat) Mosul Hit IQ AM IQ AM 5 9301 9303 9304 9305 9306 9351 9352 9357 Xijiang Huanghe Huai Changjiang Changjiang Luanhe Yongding Changjiang Wuzhou 3 Sanmenxia Bengbu Hankou (Wuhan) Datong Luanxian Guanting Yichang CN CN CN CN CN CN CN CN AS AS AS AS AS AS AS AS 9331 9332 9333 9334 9335 Tone Yodo Ishikari Chikugo Shinano Kurihashi Hirakata Ishikari-Ohashi Senoshita Ojiya JP JP JP JP JP AS AS AS AS AS 9300 Chao Phraya Khai Chira Prawat/Nakhon Sawan (C.2) TH AS 9718 9719 9722 Ord Fitzroy Burdekin Old Ord Homestead Dimond Gorge Clare AU AU AU AU AU AU Devolli Mati Erzeni Drin i Zi Osumi Shkumbini [Medhycos] Kokel Shoshaj Ndroq (Ndreq) Ura e Dodes (Skavice) Ura Vajgurere Papër AL AL AL AL AL AL 9762 Maritza Plovdiv BG EU 9765 Elbe (Labe) Decin CZ EU 9763 Danube Ceatal Izmail RO EU Dee (Royal Dee) Trent Spey Tay Tweed Bedford Ouse Stour Taw Thames (gauged) Woodend Colwick Boat o Brig Ballathie Norham Bedford Langham Umberleigh Kingston UK UK UK UK UK UK UK UK UK 9738 9739 9742 Velika Morava Danube Sava Lubicevsky Most (Serbia) Bezdan (Serbia) Sremska Mitrovica (Serbia) YU EU YU EU YU EU 9504 9518 9527 Fraser Niagara Fraser Hope Queenston Marguerite CA NA CA NA CA NA Kootenai (Kootenay) Kootenai (Kootenay) nr Copeland ID Porthill, ID US NA US NA 9526 9617 Columbia Columbia International Boundary (Canada) Int Boundary (USA), WA CA NA US NA 9645 Rio Grande (Bravo) Matamoros, MX / Brownsville, TX US NA Parana Corrientes AR SA Parana Sao Francisco Guaira Juazeiro BR SA BR SA 9745 9747 9749 9750 9751 10125 9805 9808 9809 9810 9811 9815 9816 9817 10126 9505 10100 10113 9380 9381 6 EU EU EU EU EU EU EU EU EU EU EU EU EU EU EU 9386 9387 9389 9390 9391 9379 9382 9385 9383 9388 Xingu Tocantins Araguaia Tocantins Sao Francisco Amazon Paraiba do Sul Madeira Iguaçu (Iguazu) Parnaiba Altamira Porto Nacional Conceiçao do Araguaia Itupiranga Traipu Obidos Campos Porto Velho Salto Osorio Porto Formoso BR BR BR BR BR BR BR BR BR BR SA SA SA SA SA SA SA SA SA SA • most updated gauges gained recent data, but some gained old records • the Tigris and Euphrates gauges acquired 18 and 11 years respectively of old data from the 1920s–1950s • the Huang @ Sanmenxia, China acquired 1953-1958 • seven other Chinese gauges acquired a few years of data from 1985–1989 according to availability at individual sites • for Luanhe @ Luanxian, China, previously deleted abnormally low 1980–1983 records have been restored as legitimate [see notes] • Japanese gauges acquired some recent records for the 1990s • • Albanian gauges were updated via MED-HYCOS the record Shkumbini [Medhycos] @ Papër was added as an alternate because discharges differ perceptibly from the former record and the correct choice is unclear • three Canadian gauge records were replaced entirely with more recent versions complete to 1990 the redundant record Columbia @ International Boundary (Canada) was deleted in favour of the Columbia @ International Boundary (USA) record which can be updated from US sources — this appears to be a jointly operated gauge that appears in the archives of both nations • • • • Kootenai nr Copeland, ID was falsely identified in UNESCO files as a Canadian gauge this record has been replaced with another US gauge [Kootenai @ Porthill, ID] which has a longer record and is virtually co-located with Kootenai nr Copeland which was de-activated in 1992 the record previously identified as Bravo @ Matamoros, MX is a jointly operated US/Mexican gauge [Rio Bravo is the Mexican name for Rio Grande] 7 • for operational purposes, this has been re-designated as a US gauge, re-named Rio Grande (Bravo) @ Matamoros, MX / Brownsville, TX; and updated from the US-Mexico International Boundary Waters Commission • three Australian gauge records were replaced entirely with more recent versions complete to the late 1990s • 12 Brazilian records were replaced or updated with recent versions of the gauge records available from the Brazilian agency ANEEL • at scattered sites not listed above, there were minor fixes involving 0s that should have been reported as missing values, missing values that should have been 0s, and correction of scattered typos — these corrections have almost no effects on the summary statistics, but may affect modelling of some data series Warning: MED-HYCOS Copyright / Disclaimer March 2001 • • as of late February 2001, revised MED-HYCOS www pages prominently display the following Copyright / Disclaimer statements which had not been displayed previously during 1999 and 2000 when MED-HYCOS data incorporated into the present set were retrieved it is unclear how copyright could be applied retrospectively to data previously made available without restrictions; though it would apply to any future updates from the MED-HYCOS archive COPYRIGHT : All data and information available belong to the national hydrological services. For any use, information (text, pictures, maps, tools, etc.) and hydrometeorological data, one must require the agreement of the concerned national hydrological service. Commercial use is strictly forbidden. DISCLAIMER : In any case, the responsibility of the national hydrological services and of the MED-HYCOS Project will not be engaged. • • data are still available for retrieval from the MED-HYCOS www site possession of MED-HYCOS data does in itself not violate the copyright • users should exercise their own judgement about how best to respond to the Copyright according the use they make of the data if data are not used, there is no issue • • • • the 19 sites listed below are common to the MED-HYCOS inventory records for the Greek and Portuguese sites were obtained independently from other sources without restriction records for the 6 Albanian sites are as given in MED-HYCOS; though, 1965-1984 of the 1st 5 records may be largely as given in UNESCO sources 8 • records for the 10 blue-shaded sites are composites that have MED-HYCOS data that may begin between 1984 and the early 1990s depending on the record ID# River Gauge GR EU PT EU PT EU 9852 9837 9834 Aliakmon Guadiana Sado Il Arion Pulo do Lobo Moinho da Gamitinha AL AL AL AL AL AL EU EU EU EU EU EU 9745 9750 9749 9747 9751 10125 Devolli Drin i Zi Erzeni Mati Osumi Shkumbini [Medhycos] Kokel Ura e Dodes (Skavice) Ndroq (Ndreq) Shoshaj Ura Vajgurere Papër BG ES ES FR IT RO YU YU YU TN EU EU EU EU EU EU EU EU EU AF 9762 9843 9844 9802 9851 9763 9739 9742 9738 9127 Maritza Ebro Ebro Rhone Tiber (Tevere) Danube Danube Sava Velika Morava Medjerda Plovdiv Tortosa Zaragoza Beaucaire Ripetta (Roma) Ceatal Izmail Bezdan (Serbia) Sremska Mitrovica (Serbia) Lubicevsky Most (Serbia) Ghardimaou 9 Table of Contents DISCLAIMER .......................................................................................................................................... 2 PREFACE ............................................................................................................................................... 3 Why Annotate ................................................................................................................................ 3 How to Use This Document .......................................................................................................... 4 Distribution Package..................................................................................................................... 4 Updates: July 2001...................................................................................................................... 5 Updates: March 2001................................................................................................................... 5 Warning: MED-HYCOS Copyright / Disclaimer March 2001.................................................... 8 TABLE OF CONTENTS........................................................................................................................ 10 PART I: PRELIMINARIES.................................................................................................................... 21 1.0 Introduction ............................................................................................................................... 21 1.1 Objectives .............................................................................................................................. 22 2.0 Data Sets .................................................................................................................................... 22 2.1 IHD.......................................................................................................................................... 23 2.2 WMO....................................................................................................................................... 24 2.3 RIV (RIVDIS)........................................................................................................................... 24 2.5 USA Sites in WMO/UNESCO Data Sets ................................................................................ 26 2.6 GRDC summary data............................................................................................................. 26 Caveats .................................................................................................................................... 27 3.0 Data Validation and Collation ................................................................................................... 28 3.1 Metadata Validation............................................................................................................... 28 3.1.1 Metadata Validation: Drainage Areas ............................................................................ 29 3.2 Data Validation ...................................................................................................................... 31 3.3 General Results for WMO/UNESCO Data Sets..................................................................... 32 3.3.1 Data Set Summary Statistics ......................................................................................... 33 3.4 Technical Notes..................................................................................................................... 33 3.4.1 Site Numbering Scheme ................................................................................................ 33 3.4.2 Country and Continent/Region Codes.......................................................................... 34 3.4.3 Note on Replicates ......................................................................................................... 35 3.4.4 Note on Statistical Methods — Inter-record Calibration and Adjustment................... 35 3.4.5 Note on Statistical Methods — Average Percent Difference........................................ 37 3.4.4 Note on Composited Records ....................................................................................... 37 4.0 RIVDIS Preliminaries ................................................................................................................. 38 4.1 RIV1 or RIV2.......................................................................................................................... 38 R32 Lobaye @ M'bata ............................................................................................................ 39 R1474 Aouk @ Golongoso .................................................................................................... 39 4.2 Redundant and other Junk Sites.......................................................................................... 39 4.2 Replicated Records ............................................................................................................... 40 R864 Ganges @ Paksey.......................................................................................................... 41 Niger @ Niamey and Gaya...................................................................................................... 41 4.2 Other Preliminary RIV Fixes................................................................................................. 41 R1461 Mekong Nakhon Phanom ............................................................................................ 41 10 R1462 Madelena @ Madelena................................................................................................. 41 Iraq and Costa Rica — Time-shifted Records ....................................................................... 42 5.0 WMO Preliminaries ................................................................................................................... 42 5.1 Replicated Data ..................................................................................................................... 42 W9739 Danube @ Bezdan (Serbia)......................................................................................... 42 W9848 Po @ Pontelagoscuro ................................................................................................. 42 W9850 Adige @ Boara Pisani ................................................................................................. 43 W9877 Danube @ Orsova (1971:Drobata-Turnu Severin) ..................................................... 43 W9799 Loire @ Montjean ........................................................................................................ 43 Niger River @ Niamey and Gaya ............................................................................................ 43 W9446 Colorado @ Buta Ranquil........................................................................................... 44 5.2 Other WMO Fixes .................................................................................................................. 44 Replicated Sites ...................................................................................................................... 44 Mekong River Gauges – Thailand .......................................................................................... 44 PART II: ANNOTATIONS FOR MONTHLY DISCHARGE DATA BY CONTINENT/REGION AND COUNTRY ............................................................................................................................................ 45 6.0 Africa .......................................................................................................................................... 45 Africa: Benin................................................................................................................................ 45 Mekrou @ Barou ..................................................................................................................... 45 Mono @ Athieme — Warning GRDC muddle......................................................................... 46 Ouémé @ Bonou..................................................................................................................... 47 Africa: Burkina Faso ................................................................................................................... 48 Black Volta @ Dapola ............................................................................................................. 48 Africa: Cameroon ........................................................................................................................ 49 Cameroon: General Remarks ................................................................................................ 49 Benoue @ Garoua................................................................................................................... 49 Dja @ Somalomo..................................................................................................................... 50 Mbam @ Goura ....................................................................................................................... 50 Noun @ Bafoussam / Nkam @ Melong .................................................................................. 50 Sanaga @ Edea ....................................................................................................................... 51 Sanaga @ Nachtigal................................................................................................................ 51 Wouri @ Yabassi..................................................................................................................... 52 Africa: Central African Republic................................................................................................. 52 Aouk @ Golongoso................................................................................................................. 52 Chinko @ Rafai ....................................................................................................................... 52 Lobaye @ M'bata..................................................................................................................... 53 M'Bomou @ Zemio.................................................................................................................. 53 Oubangui @ Bangui ............................................................................................................... 54 Ouham @ Bossangoa ............................................................................................................. 58 Sangha @ Salo........................................................................................................................ 58 Africa: Chad................................................................................................................................. 58 Chari @ Ndjamena (Fort Lamy) .............................................................................................. 58 Logone @ Bongor................................................................................................................... 59 Logone @ Moundou ............................................................................................................... 59 Ouham (Sara) @ Moissala ...................................................................................................... 60 Africa: Congo .............................................................................................................................. 60 Foulakary @ Kimpanzou ........................................................................................................ 60 Kouilou @ Sounda.................................................................................................................. 60 Nkeni @ Gamboma ................................................................................................................. 61 Sangha @ Ouesso .................................................................................................................. 61 11 Africa: Congo / Congo (Zaire)..................................................................................................... 61 Congo @ Brazzaville / Congo @ Kinshasa.......................................................................... 61 Congo @ Kinshasa ................................................................................................................. 61 Congo @ Brazzaville............................................................................................................... 62 Africa: Egypt................................................................................................................................ 62 Nile Basin Drainage Area Estimates ...................................................................................... 62 Nile @ Aswan .......................................................................................................................... 63 Nile @ El Ekhsase ................................................................................................................... 65 Nile @ Esna (Isna)................................................................................................................... 65 Nile @ Naga Hammadi ............................................................................................................ 66 Africa: Ethiopia............................................................................................................................ 66 Blue Nile @ nr Lake Tana ....................................................................................................... 66 Africa: Ghana............................................................................................................................... 67 Volta @ Senchi (Halcrow)....................................................................................................... 67 Black Volta @ Bamboi ............................................................................................................ 67 White Volta @ Yorugu (Yarigo) .............................................................................................. 67 Africa: Guinea.............................................................................................................................. 68 Milo @ Kankan ........................................................................................................................ 68 Niger @ Kouroussa................................................................................................................. 68 Tinkisso @ Ouaran ................................................................................................................. 69 Africa: Ivory Coast (Cote d’Ivoire) .............................................................................................. 70 Bandama @ Tiassale .............................................................................................................. 70 Cavally (Cavalla) @ Tai ........................................................................................................... 70 Cavally (Cavalla) @ Tate ......................................................................................................... 71 Comoe @ Serebou .................................................................................................................. 71 Comoe @ Aniassue................................................................................................................. 71 Africa: Kenya ............................................................................................................................... 72 Tana @ Garissa....................................................................................................................... 72 Africa: Liberia .............................................................................................................................. 73 Warning: Poor Quality Data................................................................................................... 73 Cestos @ Sawolo .................................................................................................................... 74 Cestos @ Unification Bridge .................................................................................................. 75 Saint John @ Baila.................................................................................................................. 75 Africa: Madagascar ..................................................................................................................... 76 Ikopa @ Antsatrana................................................................................................................. 76 Mahavavy Nord @ Ambilobe .................................................................................................. 77 Mananara @ Maroangaty ........................................................................................................ 77 Mangoky Bevoay / Banian .................................................................................................... 78 Africa: Mali................................................................................................................................... 79 Warning – Multiple Versions .................................................................................................. 79 Bafing @ Dibia ........................................................................................................................ 79 Baoule @ Dioila....................................................................................................................... 80 Bakoy @ Oualia....................................................................................................................... 81 Faleme @ Fadougou............................................................................................................... 82 Faleme @ Gourbassy.............................................................................................................. 82 Sankarani @ Gaoula ............................................................................................................... 83 Senegal @ Galougo ................................................................................................................ 83 Senegal @ Kayes .................................................................................................................... 85 Africa: Mauritius .......................................................................................................................... 85 Deep @ Pont Lardier............................................................................................................... 85 Africa: Niger................................................................................................................................. 85 Komadougou Yobe @ Bagara Diffa ....................................................................................... 85 Africa: Rwanda ............................................................................................................................ 86 Kagera and Nyabarongo Rivers ............................................................................................. 86 12 Africa: Senegal ............................................................................................................................ 86 WARNING — RIV Time-Shift: Jan–Apr 1976–1979................................................................ 86 Faleme @ Kidira ...................................................................................................................... 87 Gambie @ Kedougou / Gouloumbou..................................................................................... 88 Gambie @ Wassadou amont / aval ........................................................................................ 90 Senegal @ Bakel ..................................................................................................................... 91 Niokolo-Koba @ Pont Routier ................................................................................................ 91 Africa: Somalia ............................................................................................................................ 91 Shebelle @ Belet Uen ............................................................................................................. 92 Shebelle @ Buulo Barde (Bulo Berti)..................................................................................... 92 Africa: South Africa..................................................................................................................... 92 Limpopo @ Oxenham Ranch ................................................................................................. 92 Orange @ Upington ................................................................................................................ 93 Vaal @ de Hoop 65.................................................................................................................. 93 Africa: South Africa / Zimbabwe................................................................................................. 93 Limpopo @ Beitbrug / Beitbridge Pumpstation c/s .............................................................. 93 Africa: Sudan............................................................................................................................... 96 Nile Basin Drainage Area Estimates ...................................................................................... 96 Atbara @ Kilo 3 ....................................................................................................................... 96 Blue Nile @ Khartoum ............................................................................................................ 97 White Nile (el Jabel) @ Mongalla............................................................................................ 98 Africa: Sudan / Ethiopia.............................................................................................................. 99 Blue Nile @ Sudan border ...................................................................................................... 99 Africa: Tanzania ........................................................................................................................ 100 Great Ruaha @ Mtera............................................................................................................ 100 Kilombero @ Swero .............................................................................................................. 100 Rufiji @ Stiegeler's Gorge .................................................................................................... 101 Ruvu @ Dar-Es-Salam—Morogoro Rd Bridge..................................................................... 102 Africa: Togo............................................................................................................................... 102 Mono @ Dotekope (Kolokope, Correkope ?)...................................................................... 102 Oti @ Mango (Sansanne-Mango) ......................................................................................... 103 Africa: Tunisia ........................................................................................................................... 103 Medjerda @ Ghardimaou...................................................................................................... 103 Africa: Uganda........................................................................................................................... 104 Nile Basin Drainage Area Estimates .................................................................................... 104 Manafwa @ Bulucheke/Butaleja — WARNING: dubious record......................................... 104 Muzizi @ Hoima-Fort Portal Rd ............................................................................................ 105 Africa: Zambia ........................................................................................................................... 105 Kabompo ? @ Manyinga Rd Bridge..................................................................................... 105 Africa: Zimbabwe ...................................................................................................................... 106 Gwaai @ Kamativi g/w .......................................................................................................... 106 Hunyani (Manyame ?) @ Mangula Mine Weir ...................................................................... 106 Mazoe @ Lion's Den g/w ...................................................................................................... 107 Sabi @ Condo d/s g/w .......................................................................................................... 107 7.0 Asia........................................................................................................................................... 108 Asia: China ................................................................................................................................ 108 Note on Chinese River Names.............................................................................................. 108 Changjiang @ Datong........................................................................................................... 108 Changjiang @ Hankou (Wuhan)........................................................................................... 108 Changjiang @ Yichang ......................................................................................................... 109 Dongjiang @ Boluo............................................................................................................... 109 Huaihe @ Bengbu ................................................................................................................. 109 Huanghe @ Sanmenxia / Shanxian...................................................................................... 110 13 Luanhe @ Luanxian .............................................................................................................. 111 Songhua @ Haerbin.............................................................................................................. 111 Songhua @ Jilin.................................................................................................................... 112 Xijiang @ Wuzhou 3.............................................................................................................. 113 Yongding @ Guanting .......................................................................................................... 113 Yujiang @ Nanning ............................................................................................................... 114 Asia: India / Bangladesh ........................................................................................................... 114 Brahmaputra @ Bahadurabad.............................................................................................. 114 River Ganges (Ganga)........................................................................................................... 114 Asia: India.................................................................................................................................. 115 Bhima @ Yadgiri / Krishna @ Devarsugur (Deosugur ?).................................................... 115 Brahmani @ Barakot Bridge................................................................................................. 116 Cauvery River Gauges .......................................................................................................... 116 Indrawati @ Parthgudem ...................................................................................................... 117 Kalinadi @ Dundeli ............................................................................................................... 117 Asia: Iran.................................................................................................................................... 118 WARNING — Questionable Data Quality ............................................................................. 118 WARNING — Time-Shift 1980–1984 !!!!................................................................................ 118 Ghezalozan (Qezel Owzan) @ Gilvan................................................................................... 119 Halil @ Hossein Abad Jiroft ................................................................................................. 120 Karkheh (Al Karkha) @ Hamidiyeh....................................................................................... 120 Karun @ Ahvaz / Pol-e-Shalu ............................................................................................... 120 Kor @ Ahmadabad / Kor @ Ahmadabad Dorudzan .......................................................... 122 Lar @ Ploor ........................................................................................................................... 125 Minab @ Berantin.................................................................................................................. 125 Shafa @ Poonel..................................................................................................................... 125 Zayandeh @ Pol-e Khaju / Pol-e Kaloh (Pol-e Kaleh ?) ...................................................... 126 Asia: Japan ................................................................................................................................ 127 Warning: Bad UNESCO/GRDC data some years (1960, 1965, 1966).................................. 127 Ishikari @ Ishikari-Ohashi .................................................................................................... 127 Chikugo @ Senoshita ........................................................................................................... 128 Shinano @ Ojiya ................................................................................................................... 129 Tone @ Kurihashi ................................................................................................................. 129 Yodo @ Hirakata ................................................................................................................... 130 Asia: Korea, North..................................................................................................................... 131 North Korea: Six sites with additional data not in UNESCO files ..................................... 131 Asia: Malaysia............................................................................................................................ 131 Malaysia: General Remarks ................................................................................................. 131 Johor @ Rantau Panjang...................................................................................................... 132 Kelantan @ Guillemard Bridge............................................................................................. 132 Krian @ Dusun Limai............................................................................................................ 134 Langkat @ Dingkil................................................................................................................. 134 Pahang @ Temerloh ............................................................................................................. 135 Perak @ Iskandar Bridge ...................................................................................................... 135 Selangor @ Rantau Panjang ................................................................................................ 135 Sembrong @ Brizay Bridge .................................................................................................. 136 Trengganu @ Kampung Tanggol......................................................................................... 136 Asia: Mongolia........................................................................................................................... 137 General Remarks................................................................................................................... 137 Asia: Pakistan............................................................................................................................ 138 Indus @ Attock / Kotri........................................................................................................... 138 Asia: Philippines ....................................................................................................................... 139 Cagayan @ Pangal / Palattao ............................................................................................... 139 Pampanga @ San Agustin, Arayat ....................................................................................... 139 14 Asia: Singapore......................................................................................................................... 140 Bukit Timah Canal @ Bukit Timah Rd, km 10...................................................................... 140 Asia: Sri Lanka .......................................................................................................................... 140 Gin Ganga @ Agaliya............................................................................................................ 140 Kelani Ganga @ Glencourse ................................................................................................ 141 Mahaweli Ganga @ Manampitiya ......................................................................................... 141 Mahaweli Ganga @ Peradeniya............................................................................................ 141 Malwatu Oya @ Kapachchi................................................................................................... 142 Asia: Thailand ........................................................................................................................... 142 Thailand: Warning................................................................................................................ 143 Chao Phraya @ Khai Chira Prawat/Nakhon Sawan............................................................. 143 Chi @ Yasothon .................................................................................................................... 143 Mekong River – Warning: Mis-scaled data .......................................................................... 143 Mekong @ Chiang Saen ....................................................................................................... 144 Mekong @ Mukdahan ........................................................................................................... 144 Mun @ Ubon Ratchathani..................................................................................................... 147 Tapi @ Surat Thani ............................................................................................................... 148 Trang @ Trang ...................................................................................................................... 148 Asia: Thailand / Laos ................................................................................................................ 148 Mekong @ Nakhon Phanom / Thakhek................................................................................ 148 8.0 Middle East .............................................................................................................................. 149 Middle East: Cyprus.................................................................................................................. 149 Limnitis @ Limnitis Saw Mill ................................................................................................ 149 Middle East: Iraq ....................................................................................................................... 149 Tigris and Euphrates ............................................................................................................ 149 Middle East: Israel..................................................................................................................... 150 Jordan @ Southern Stn / Jordan @ Obstacle Bridge ....................................................... 150 Middle East: Jordan .................................................................................................................. 150 Zerqa @ Jerash Bridge / Yarmouk @ Maqarin .................................................................. 150 Middle East: Syria ..................................................................................................................... 151 Euphrates @ Kadaheyah / Yusuf Basha .............................................................................. 151 9.0 Australia ................................................................................................................................... 151 General Remarks................................................................................................................... 151 Burdekin @ Clare .................................................................................................................. 152 Daly @ Gourley / Mount Nancar ........................................................................................... 153 Fitzroy @ Yaamba / The Gap................................................................................................ 153 Victoria @ Coolibah Homestead .......................................................................................... 154 10.0 Pacific Ocean ......................................................................................................................... 154 Pacific Ocean: New Zealand ..................................................................................................... 154 Buller @ Te Kuha .................................................................................................................. 154 Cleddau @ Milford ................................................................................................................ 155 Clutha @ Balclutha ............................................................................................................... 155 Clutha @ Clyde ..................................................................................................................... 155 Hutt @ Kaitoke ...................................................................................................................... 155 Omakere @ Fordale .............................................................................................................. 156 Selwyn @ Whitecliffs ............................................................................................................ 156 Waikato @ Lake Taupo Outlet.............................................................................................. 156 Wanganui @ Paetawa ........................................................................................................... 157 Pacific Ocean: Papua New Guinea........................................................................................... 157 Purari @ Wabo Dam site....................................................................................................... 157 Tauri @ Hells Gate ................................................................................................................ 158 15 11.0 Europe.................................................................................................................................... 158 Europe: Albania......................................................................................................................... 158 Albanian Gauges Updated from MED-HYCOS..................................................................... 158 Drin @ Kalimash / Vau i Dejes............................................................................................. 158 Shkumbini @ Papër .............................................................................................................. 159 Europe: Bulgaria ....................................................................................................................... 160 Two sites with additional data from independent sources ................................................ 160 Maritza @ Kharmanli (Harmanli)........................................................................................... 160 Struma @ Razdavitza / Krupnik............................................................................................ 161 Europe: Czech Republic ........................................................................................................... 161 Elbe (Labe) @ Decin ............................................................................................................. 161 Europe: Finland......................................................................................................................... 162 Kemi @ Taivalkoski .............................................................................................................. 162 Kymi @ Pernoo ..................................................................................................................... 162 Vuoksi @ Imatra .................................................................................................................... 162 Europe: France.......................................................................................................................... 163 Garonne @ Mas-d'Agenais ................................................................................................... 163 Rhone @ Beaucaire — Warning: potential drainage area decrease due to diversion ...... 163 Rhone @ La Mulatiere / Givors ............................................................................................ 164 Europe: Germany ...................................................................................................................... 164 Elbe @ Darchau..................................................................................................................... 164 Elbe @ Wittenberge .............................................................................................................. 165 Europe: Greece ......................................................................................................................... 165 Aliakmon @ Il Arion .............................................................................................................. 165 Europe: Hungary ....................................................................................................................... 166 Danube @ Nagymaros .......................................................................................................... 166 Tisza @ Polgar / Tiszapalkonya ........................................................................................... 167 Europe: Iceland ......................................................................................................................... 167 General Remarks................................................................................................................... 167 Europe: Ireland.......................................................................................................................... 168 Shannon @ Killaloe .............................................................................................................. 168 Europe: Italy .............................................................................................................................. 168 Po @ Boretto ......................................................................................................................... 168 Po @ Pontelagoscuro........................................................................................................... 169 Tiber (Tevere) @ Ripetta (Roma).......................................................................................... 169 Europe: Norway......................................................................................................................... 170 Glomma @ Langnes (Solbergfoss)...................................................................................... 170 Europe: Portugal ....................................................................................................................... 171 General Remarks................................................................................................................... 171 Douro @ Regua..................................................................................................................... 171 Mondego @ Coimbra ............................................................................................................ 172 Tagus (Tejo) @ Vila Velha de Rodão ................................................................................... 172 Europe: Romania ...................................................................................................................... 173 Danube @ Ceatal Izmail........................................................................................................ 173 Danube @ Orsova ................................................................................................................. 173 Mures @ Arad........................................................................................................................ 174 Europe: Serbia........................................................................................................................... 175 Danube @ Bezdan (Serbia)................................................................................................... 175 Danube @ Bogojevo (Serbia) ............................................................................................... 176 Sava @ Sremska Mitrovica (Serbia) ..................................................................................... 176 Tisza (Tisa) @ Senta (Serbia) ............................................................................................... 177 Velika Morava @ Lubicevsky Most (Serbia) ........................................................................ 177 Europe: Slovakia ....................................................................................................................... 178 Danube @ Bratislava ............................................................................................................ 178 16 Europe: Spain............................................................................................................................ 179 Warning: Mis-scaled UNESCO data .................................................................................... 179 Duero @ Villachica / @ Tore (Toro ?) .................................................................................. 181 Ebro @ Zaragoza / Tortosa................................................................................................... 181 Europe: Sweden ........................................................................................................................ 181 Angerman @ Solleftea .......................................................................................................... 181 Lule @ Boden Waterworks ................................................................................................... 182 Europe: Switzerland.................................................................................................................. 182 Rhine @ Basel (St. Alban) .................................................................................................... 182 Rhone @ Chancy .................................................................................................................. 183 Europe: UK ................................................................................................................................ 183 Recent UK data now available on-line ................................................................................. 183 Warning: Gauged versus Naturalized Discharge Data........................................................ 183 Bedford Ouse @ Bedford ..................................................................................................... 184 Severn @ Bewdley ................................................................................................................ 184 Thames @ Kingston / Teddington [naturalized] ................................................................. 185 Thames @ Kingston / Teddington [gauged versus naturalized]........................................ 185 Wharfe @ Flint Mill Weir ....................................................................................................... 186 12.0 North America ........................................................................................................................ 186 North America: USA .................................................................................................................. 186 North America: Canada............................................................................................................. 186 Canada: General Remarks .................................................................................................... 186 Assiniboine @ Brandon / nr Brandon.................................................................................. 187 Back River ............................................................................................................................. 187 Columbia @ Birchbank......................................................................................................... 187 Columbia @ International Boundary — Deleted ................................................................. 188 Gods River............................................................................................................................. 188 Harricana @ Amos ................................................................................................................ 188 Kootenay / Kootenai @ nr Copeland, ID — reassigned to USA & replaced....................... 189 Moose @ Moose River / u/s Moose River ............................................................................ 189 Natashquan ........................................................................................................................... 190 Petit Mecatina........................................................................................................................ 191 Saint John @ Pokiok / d/s Mactaquac ................................................................................. 191 Saint-Maurice @ Centrale de Grande-Mere ......................................................................... 191 St. Lawrence @ Cornwall ..................................................................................................... 192 Stikine @ Telegraph Ck / Porcupine @ Old Crow............................................................. 193 Thompson @ nr Spences Bridge......................................................................................... 193 North America: Mexico.............................................................................................................. 193 Warning: Dubious records at some gauges....................................................................... 193 Conchos @ Ojinaga .............................................................................................................. 194 Grijalva @ Reforma / Rompido de Samaria @ Samaria ...................................................... 194 San Pedro @ San Pedro ....................................................................................................... 196 Usumacinta @ Boca del Cerro — WARNING mis-scaled 1965–1968 data ......................... 196 13.0 Caribbean............................................................................................................................... 197 Caribbean: Cuba ...................................................................................................................... 197 Four sites with data not in UNESCO.................................................................................... 197 Caribbean: Dominican Republic ............................................................................................. 198 Yuna @ El Limon .................................................................................................................. 198 14.0 Central America ..................................................................................................................... 198 Central America: El Salvador................................................................................................... 198 Grande de San Miguel @ Vado Marin / @ Las Conchas..................................................... 198 17 Lempa @ Colima ................................................................................................................... 200 Lempa @ San Marcos ........................................................................................................... 200 Paz @ La Hachadura............................................................................................................. 201 Central America: Guatemala..................................................................................................... 201 Warning: Dubious records at some gauges....................................................................... 201 Chixoy @ San Augustin / La Pasion @ El Porvenir .......................................................... 202 San Pedro @ San Pedro Mactun .......................................................................................... 202 Central America: Nicaragua...................................................................................................... 202 Warning: GRDC muddle ...................................................................................................... 202 Viejo @ La Lima / Santa Barbera.......................................................................................... 203 Tamarindo @ Tamarindo...................................................................................................... 203 15.0 South America ....................................................................................................................... 204 South America: Argentina ........................................................................................................ 204 General Remarks — UNESCO data sources........................................................................ 204 General Remarks — R-Hydronet .......................................................................................... 204 Warning: Confusing River Names & Muddled Records..................................................... 205 Bermejo @ Zanja del Tigre ................................................................................................... 206 Chimehuin @ Huechulaufquen ............................................................................................ 206 Colorado @ Buta Ranquil..................................................................................................... 207 Colorado @ Pichi Mahuida................................................................................................... 207 Limay @ Paso Flores ............................................................................................................ 208 Limay @ Paso Limay ............................................................................................................ 209 Negro @ Primera Angostura ................................................................................................ 209 Neuquen @ Paso de Los Indios........................................................................................... 210 Parana @ Corrientes............................................................................................................. 211 Parana @ Paso’s ................................................................................................................... 214 Pasaje / Juramento @ Miraflores ....................................................................................... 214 Salado @ El Arenal ............................................................................................................... 216 Salado @ Achupallas............................................................................................................ 217 Salado @ H.C.Casanas ......................................................................................................... 217 Sali Dulce @ El Sauce (1967: Embalse Rio Hondo) — Warning: probable composite ..... 217 San Juan @ La Puntilla/Dique I. de la Rosa ........................................................................ 220 Tercero @ Embalse Ministro Juan Pistarini ........................................................................ 220 South America: Argentina / Uruguay ....................................................................................... 222 Uruguay @ Salto and Uruguay @ Concordia ...................................................................... 222 South America: Bolivia ............................................................................................................ 222 Beni @ Angosto del Bala...................................................................................................... 222 Desaguadero @ Ulloma ........................................................................................................ 223 Grande @ Abapó................................................................................................................... 223 South America: Brazil .............................................................................................................. 224 On-line data now available ................................................................................................... 224 Amazon @ Obidos ................................................................................................................ 225 Warning: multiple versions & dubious records for Amazon @ Obidos ............................ 226 Potential Problem: 1968–1969 ............................................................................................. 227 Jequitinhonha @ Jacinto...................................................................................................... 228 Parnaiba @ Porto Formoso / Luzilandia composite ........................................................... 228 South America: Chile ................................................................................................................ 229 Bio Bio @ Desembocadura .................................................................................................. 229 Baker @ La Colonia .............................................................................................................. 229 Limari @ Panamericana........................................................................................................ 229 Maipo @ Cabimbao............................................................................................................... 230 Rapel @ Corneche ................................................................................................................ 230 South America: Colombia......................................................................................................... 230 18 Atrato @ Tagachi .................................................................................................................. 231 Cauca @ La Pintada.............................................................................................................. 231 Magdalena @ Calamar .......................................................................................................... 231 Magdalena @ Puente Santander .......................................................................................... 231 Meta @ Puente Lleras ........................................................................................................... 231 San Juan @ Penitas.............................................................................................................. 232 South America: Ecuador........................................................................................................... 232 General Remarks................................................................................................................... 232 WARNING — Drainage Area Uncertainties .......................................................................... 233 WARNING — Time-shift: Quevedo @ Quevedo / Vinces @ Vinces................................... 233 Chimbo @ Bucay .................................................................................................................. 234 Quevedo @ Quevedo............................................................................................................ 234 Zapotal @ Lechugal .............................................................................................................. 235 South America: Guyana............................................................................................................ 235 Essequibo @ Plantain Island ............................................................................................... 235 Cuyuni @ Kamaria Falls ....................................................................................................... 236 South America: Peru ................................................................................................................. 236 Majes (Camaná) @ Huatiapa................................................................................................. 236 Ramis @ Pte Saman (Pte Carretera)..................................................................................... 236 Santa @ Pte Carretera........................................................................................................... 237 South America: Surinam........................................................................................................... 237 Nickerie @ Stondansie ......................................................................................................... 237 South America: Surinam / French Guiana ............................................................................... 237 Maroni (Marowijne, Lawa) @ Langa Tabbetje / Langa Tabiki............................................. 237 South America: Uruguay........................................................................................................... 238 Negro @ Paso Pereira........................................................................................................... 238 South America: Venezuela........................................................................................................ 239 Apure @ San Fernando de Apure ........................................................................................ 239 Bocono @ Pena Larga .......................................................................................................... 239 Escalante @ Laferreira.......................................................................................................... 239 Guasare @ El Carbon ........................................................................................................... 240 Masparro @ Pte Masparro .................................................................................................... 240 Orinoco @ Laja de Musiu Ignacio (Musinacio ?) ................................................................ 240 Orinoco @ Ciudad Bolivar (Angostura) / Puente Angostura.............................................. 241 Neveri @ La Corcovada ........................................................................................................ 242 Tocuyo @ Puente Torres...................................................................................................... 242 Tuy @ El Clavo (El Vigia ?) .................................................................................................. 242 Uribante Pte @ Puente Uribante .......................................................................................... 242 16.0 US Data................................................................................................................................... 243 16.1 US data sources ................................................................................................................ 243 A. Metadata........................................................................................................................... 244 B. USGS Gauge Codes ........................................................................................................ 244 16.2 Unofficial US Data in UNESCO and other sources not available from USGS ................ 244 16.2.1 Caveats ....................................................................................................................... 245 16.3 Drainage Areas .................................................................................................................. 245 16.3.1 Drainage Areas Given in this data set....................................................................... 247 16.4 Lower Mississippi and Atchafalaya.................................................................................. 247 16.4.1 General Background .................................................................................................. 248 16.4.2 US Army Corps of Engineers gauges ....................................................................... 249 16.4.3 Estimating Total Discharge of the Mississippi–Atchafalaya System ...................... 250 16.5 Pseudo Records ................................................................................................................ 251 16.5.1 Mississippi @ Red River Landing and Atchafalaya @ Simmesport ........................ 251 16.5.2 St. Lawrence River @ Ogdensburg / St. Lawrence @ Cornwall/Massena............... 251 19 16.5.3 Miscellaneous Doppelgangers .................................................................................. 252 16.6 Discontinuations and muddled substitutions ................................................................. 253 16.7 Boundary Gauges.............................................................................................................. 254 Colorado River — International (US–Mexico) Boundary .................................................... 254 Rio Grande / Bravo — International (US–Mexico) Boundary.............................................. 255 Columbia @ International Boundary (US–Canada)............................................................. 255 Kootenai @ nr Copeland, ID replaced with Kootenai @ Porthill, ID .................................. 256 17.0 Niger River Mid-basin Gauges ............................................................................................. 258 17.1 General Remarks ............................................................................................................... 258 17.1.1 Problem Gauge Records............................................................................................ 259 17.2 Niger River Metadata — Uncertain Gauge Drainage Areas ............................................ 259 17.3 Independently Obtained Daily Data Sets ......................................................................... 260 17.3.1 Estimating monthly means from incomplete daily records ..................................... 261 17.3.2 Missing Feb 1 of Leap Years: sites 9045, 9046 and 9898 ........................................ 262 17.4 Niger @ Koulikoro ............................................................................................................. 262 17.5 Niger @ Kirango ................................................................................................................ 264 1925 – Oct 1950 ..................................................................................................................... 264 Nov 1950 – 1990 .................................................................................................................... 266 Data Retained ........................................................................................................................ 266 17.6 Bani @ Douna.................................................................................................................... 266 17.6.1 Estimated Monthly Averages for Months with Incomplete Daily Discharges ......... 268 17.6.2 1922–1933 ................................................................................................................... 268 17.6.3 1934 – Oct 1951........................................................................................................... 270 17.6.4 Oct 1951 – Dec 1981 .................................................................................................. 270 17.6.5 Data Retained ............................................................................................................ 270 17.6.6 Missing months estimated from RIV and WMO....................................................... 271 17.7 Niger @ Mopti .................................................................................................................... 271 17.7.1 UNESCO data not in IND............................................................................................ 275 17.8 Niger @ Dire....................................................................................................................... 276 17.8.1 UNESCO data not in IND............................................................................................ 279 17.9 Niger @ Ansongo .............................................................................................................. 279 17.10 Niger @ Niamey, Malanville and Gaya............................................................................ 280 17.10.1 Niger @ Niamey ........................................................................................................ 281 17.10.2 Niger @ Malanville.................................................................................................... 286 17.10.3 Niger @ Gaya............................................................................................................ 288 References:.................................................................................................................................... 290 20 Part I: Preliminaries 1.0 Introduction The first compilation of global river discharges was a modest set of data for 365 stream gauges compiled during the UNESCO sponsored International Hydrologic Decade [IHD] program of the 1960s and early 1970s. UNESCO continued to assemble data submitted by various nations, but little happened until the early 1990s when interest in climate change, impending water shortages and other water-related problems re-vitalized interest in global hydrological data sets. Hydrologic data submitted to UNESCO have since been released in two alternate compilations of data for about 1,050 global stream gauges. These data sets are openly published and freely available. The Global Runoff Data Centre [GRDC] was organized as a central repository of global stream discharge data in 1988. GRDC has accumulated data for 5,500 or more stream gauges. Regrettably, GRDC data are accessible only to a narrow elite, and data obtained via GRDC are subject to highly restrictive terms of use. Thus, the freely available data compilations remain an important source of information for the great mass of humanity excluded from access to the GRDC data base. Also, GRDC openly disavows any commitment to data QC/QA [quality control / quality assurance]; hence, there is no guarantee that data obtained from GRDC will be of better quality than that obtained from other sources. The three UNESCO data sets (the two recent versions, and the old IHD compilation) are limited in temporal and spatial coverage, but are useful for many purposes ranging from educational to technical. The set includes gauges on many important large rivers that have been used to evaluate global water budgets and climatic model simulations (e.g., Arora and Boer, 2001; Oki et al., 1995). Moreover, these data can be used freely without the severe conditions imposed by GRDC and other regional or national sources. Each of the three UNESCO compilations contains some data not present in the others; hence, the collated files yield a single data set with more gauges and longer records. Unfortunately, there are ubiquitous discrepancies in the metadata and stream discharges within and among the three alternate versions. Thanks to the proliferation of the internet, several national and international sources of stream discharge data have become available. Numerous informal collections were also uncovered; however, as the quality and chain-of-custody of these are rarely known, these data had to be approached cautiously. Nonetheless, more data were found for many of the sites in the UNESCO files greatly improving the temporal coverage. 21 1.1 Objectives • • • • to assess the quality of metadata and discharge records in the freely available UNESCO files to identify and correct or remove dubious metadata and discharge records to collate the clean data into a single coherent set to supplement the UNESCO records with data from other sources where these were available 2.0 Data Sets The data sets considered here are listed below in Table 1. The primary concern was the integration of the UNESCO derived data sets — IHD, WMO and RIVDIS (abbreviated to RIV hereafter) — into a coherent set, as free of errors as possible. Ostensibly, these are monthly discharge data that were submitted to UNESCO by the national source agencies. Other compilations of the UNESCO data may exist, but WMO and RIV have a semblance of authority as some UNESCO sanctioned effort was made to assure data validity. Whenever possible, data were replaced with authoritative versions from national source agencies. This is only possible for the USA, the Canadian Arctic basin, and some UK, Australian and Brazilian gauges. Other than for the Canadian–US Arctic, data in R-Arcticnet do not come directly from hydrologic monitoring services and may contain errors. The Portuguese data available on-line from INAG were incomplete at the time of writing and contained some discrepancies between monthly and daily versions of the same gauge records. MED-HYCOS, like GRDC, makes no commitments to data QC/QA. Some obvious errors were present in the main Rhone River monthly discharge record at the time of writing, and differences were evident between some daily and monthly versions of other gauge records. Table 1. Data sets used. 1. IHD the old UNESCO/IHD data set with discharges to 1972 [available at NCAR from the ds552 page — see WMO below] 2. WMO NCAR data set ds552 — nominally a compilation of data submitted to WMO/UNESCO attributed to GRDC [www.scd.ucar.edu/dss/datasets/ds552.0.html] 3. RIV RIVDIS data set from ORNL — nominally a compilation of data provided to UNESCO/WMO by Vörösmarty & associates 22 [www-eosdis.ornl.gov/daacpages/rivdis.html] also at [www.RivDis.sr.unh.edu/] 4. R-arcticnet data for ca. 50 Canadian sites in the Arctic Ocean, Hudson Bay, and Ungava Bay drainage basins [www.R-arcticnet.sr.unh.edu/] 5. INAG data for 15 Portuguese sites from Insituto Nacional da Agua (INAG) [www.inag.pt/cgi-bin/snirh/callsnirh] 6a. UK-ENV data for three English gauges from the UK Environment agency [www.environment-agency.gov.uk/gui/dataset4/4nation.htm] -no longer available in early 2001, or moved to unknown URL 6b. UK-NRFA recent data (1996-1999) for UK sites from UK National River Flow Archive [www.nwl.ac.uk/ih/nrfa/index.htm] 7. MED-HYCOS data for several Mediterranean tributary gauges from MED-HYCOS [www.hycos.orstom.fr/medhycos/en/dat/] 8. USA data for 90 US sites from USGS [US Geological Survey] and other sources — see section on US 9. GRDC annual summary data (mean, maximum and minimum) for many sites in the UNESCO set [www.bafg.de/html/internat/grdc/projects/projects.html] 10. WA data for 3 Western Australian gauges [www.wrc.wa.gov.au/waterinf/wric/SearchByCriteria.asp] 12. PACRIM data for 1 Peruvian and 2 New Zealand gauges [www.seas.ucla.edu/chpr/pacrimst.htm] 13. R-Hydronet data for 15 Argentine gauges [www.R-hydronet.sr.unh.edu/] 14. ANEEL data for 12 Brazilian gauges [hidroweb.aneel.gov.br/] 15. Other alternate data for 200+ scattered global sites from independent files 2.1 IHD This data set is a digital version of data compiled during the International Hydrologic Decade program of the 1960s – early 1970s and published in paper hard copy (UNESCO, 1974). • • • IHD had 281 non-FSU sites with discharges ending in 1972 IHD time series are often short IHD data have been subjected to crude rounding to the nearest integer which obscures information for streams with low discharges, generally in arid regions or small watersheds 23 • IHD offers limited corroboration of older records, correct gauge metadata for some sites that were given incorrectly in WMO or RIV, and some extra data at a few sites that had been overlooked by WMO and RIV compilers 2.2 WMO NCAR called this data set WMO. That is short for World Meteorological Organization. WMO is ostensibly a compilation of data submitted to UNESCO that was prepared by the Global Runoff Data Centre [GRDC] in Koblenz, Germany which operates under WMO sanction. Data in the WMO set are not necessarily the data submitted to UNESCO, but data in the GRDC files for sites for which UNESCO has apparently received data. 2.3 RIV (RIVDIS) RIV is a compilation by Vörösmarty and associates of the Global Hydrology Research Group at the University of New Hampshire, apparently by complete data reentry of the data submitted to UNESCO. 2.4 WMO versus RIV WMO and RIV each have data for some sites not in the other set (Table 2). Together the collated data set has records for 957 unique non-FSU sites. The major contribution of RIV is 72 African sites not available in WMO. The collated WMO/RIV set also yielded some net gain in records for the 838 common sites; however, there were appreciable discrepancies between the two sets that had to be resolved. The 957 unique sites in the collated set are assumed to be the “UNESCO sites”; however, these may include some from WMO/GRDC that are not UNESCO sites, and these may not be a complete set of all sites for which UNESCO has data. The final number of sites that ultimately emerged from UNESCO files is slightly larger at about 962. This is mainly because some ostensibly single records that proved to be composites of two gauge records were restored back to the original distinct gauge records. Some additional records were added where gauges had been moved and a the combined long term record obtained from compositing two records would be of genuine interest. Accordingly, the final data set has 970 records Table 2. Site counts by continent or region. 24 Continent / region WMO RIV 203 21 263 20 191 20 12 1 72 275 21 144 10 39 17 124 6 143 8 37 16 117 6 142 8 37 16 117 6 2 2 2 1 7 1 145 10 39 17 124 6 c 196 194 192 4 2 198 d 14 19 13 1 6 20 97 101 96 1 5 102 924 838 33 86 957 Africa a Middle East Asia Australia Central America Caribbean Europe Indian Ocean b North America Pacific Ocean South America totals † a b c d † 871 † common WMO only RIV only WMO / RIV total counts and totals after removing some obvious replicates and unusable records. Turkey, Jordan, Israel, Cyprus, Syria, Iraq Mauritius Canada, US, Mexico New Zealand, Papua New Guinea, New Caledonia, French Polynesia, American Samoa, Guam, Micronesia, Palau, Hawaii 2.5 Other data Other independently obtained data sets have data for several hundred of these river gauges. Subsequent sections refer to these independently obtained data as if there were one or a few sources, but the data were found in numerous, usually small regional and local data sets. More than 200 of these records are ostensibly for the same sites in the UNESCO set, and often the data are identical or nearly so to concurrent data in WMO or RIV. Some of the independent data series have much longer records than are available in IHD, WMO and RIV. These long records were retained when they appeared to be genuine which was usually the case. Except for US data obtained directly from the source agency, the validity of most of these additional data could only be assessed in cursory fashion; hence, due caution is advised in using these data. Most cases where additional data from independent sources have been added to the set are identified in these notes. Some independently obtained records differ somewhat from data in WMO and RIV, and the question arises of which data are more authentic or of superior quality. The 25 issue is usually not corruption by intermediary handlers, but whether a particular data series is an old version that has remained in circulation after the national agency has released revised data. The UNESCO data ostensibly comprise annual submissions; hence, many data are the versions released years ago. IHD has data that were submitted to UNESCO 25+ years ago. National agencies may since have revised the records for some of these gauges. For certain West African countries, data for numerous gauges have multiple versions that seem to represent arbitrary re-scaling of the same source data by the compiler [human] of that particular version. Without direct access to source agency files and personnel, it is impossible to determine which version of a gauge record is superior. 2.5 USA Sites in WMO/UNESCO Data Sets Between WMO and RIV, there were ostensibly 90 gauge records for the USA. These data have so many errors and discrepancies that the initial impulse was to scrap the US sites altogether because US data are readily and freely available from the USGS [US Geological Survey]. But, these UNESCO sights may have all the US data many users want. Thus, the US sites were kept and data were replaced site-for-site from the sources listed in Section 16. This obviates the need to identify all the discrepancies present in the UNESCO versions of these records. In addition summarizing these revisions, Section 16 elaborates some particular quirks of the USGS data archive that pertain to sites in the UNESCO files and clarifies the circumstances certain boundary gauges in the UNESCO set and the discharges through the lower Mississippi–Atchafalaya system. [click to go to Section 16. USA ] 2.6 GRDC summary data In 1999, GRDC made available two sets of summary data for (A) 199 gauges on rivers discharging to the world’s oceans, and (B) 1,352 global river gauges. Set B includes most of set A; so that, the joint set represents 1,386 gauges of which 542 correspond to sites in the present data set. As given, GRDC summary data are not all that useful, but some helpful time series can be constructed with a little manipulation. For each year with at least one month of record, the summaries comprise: 1. the “annual sum” of available monthly discharge rates 26 2. the “annual mean” of available monthly mean discharge rates 3. the month and mean discharge of the month with maximum mean discharge 4. the month and mean discharge of the month with minimum mean discharge Items 1 and 2 represent the sum and average of the months reported in a calendar year. When less than 12 months are available, these “annual means” can be poor estimates of the true annual means. The number of months reported can be obtained by rounding the result of dividing the “annual sum” by the “annual average” to the nearest integer. For some low discharge sites with sum and average near 0, the month counts determined this way may be inaccurate or indeterminate due to limited digital precision. Also included are long term monthly summaries with: a) monthly means of the entire record b) monthly minima and years of occurrence for the entire record c) monthly maxima and years of occurrence for the entire record From the annual and monthly summaries, useful series can be reconstructed to assist cross-checking other monthly time series: A) a monthly time series usually with 2 non-missing months per annum (the annual minimum and maximum); and sometimes more months if the long term monthly extrema were not annual extrema, e.g., if the minimum of all January discharges that occurred in year X was not the minimum monthly discharge of year X. B) the series of “annual means” of available months, C) the series of “annual counts” of available monthly discharges. Caveats GRDC disavows any commitment to data QC/QA [quality control/quality assurance] laying the onus on the national source agencies. Unfortunately, it seems that GRDC introduces many errors during data transfer into the GRDC data base. Many of the errata outlined in this report are present in GRDC summary data. Some errors in the WMO set generated by GRDC have been corrrected, but the summary data reveal that GRDC has introduced new, and sometimes, egregious errors. The overall percentage of errata may be low, but there are enough errata that the quality of GRDC data and metadata cannot be taken for granted. Information in the GRDC gauge inventory files for the summary data sets [“freshflux.stn” and “1300stat.stn”] concerning periods of record and the percentage of missing months does not agree with the periods of record and month counts for numerous sites determined directly from the GRDC summary data. 27 Regrettably, GRDC truncated most of the underlying monthly data series to integer values. For example, a discharge of 1.99 m3/s would be truncated to 1 m3/s. Annual and long term extrema were truncated; and the sums and means were evidently calculated from truncated data. For low runoff streams with monthly and annual mean discharges frequently under 10 m3/s, this creates considerable nuisance effects when comparing other versions to GRDC series. Anyone attempting to merge the two GRDC summaries will find discrepancies between the summary data given for about 20–30 of the common sites: 1. Several cases involve US gauges with data in imperial or mixed SI and imperial units. To avoid problems, obtain data directly from US sources. 2. For some other cases, the discrepancies involve one summary having more recent data than the other. The 199 site summary seems to have more recent data, but for some common sites, the older 1,352 site summary has much longer records. 3. Some discrepancies result from one summary having monthly means derived from daily discharge series, while the other used separately obtained monthly series that likely represent different releases of the gauge record. 3.0 Data Validation and Collation 3.1 Metadata Validation Examination of the WMO/UNESCO global data sets (IHD, WMO and RIV) revealed numerous discrepancies in gauge metadata (river name, gauge location name, location coordinates, drainage areas and gauge elevations). Gauge metadata problems were identified by cross-comparisons between data sets, site mapping to evaluate geographic coordinate validity, and checks against standard references like the US NIMA gazetteer [164.214.2.59/gns/html/index.html], a gazetteer file from Digital Chart of the World, the Times Atlas, and occasionally some others. The GRDC site inventory was also used as a reference, but this has many of the same errata present in the WMO/UNESCO metadata. For the most sites in the present release, the river and gauge names are reasonably correct and given in widely accepted forms. Accented names, mostly for rivers in Latin America and French West Africa, are present where gauge metadata have been transferred from national and international gauge catalogues. Accented names have been left as is because the English spellings generally use the same letters without accent and diacritical marks. Many rivers have multiple names that vary from country to country, from reach-toreach within countries, and sometimes according to names used by different ethnic groups. Attempts have been made to assign standard names for all gauges on the 28 same river in order to facilitate sorting gauge inventory and data summaries. For example, all sites on the Euphrates are designated as Euphrates (Firat, Al Furat) where Firat is the Turkish name and Al Furat is the name in Syria and Iraq. The location coordinates are generally good, but there are sites for which the gauge locations are too obscure to be verified. For most of these, it was possible to at least assure that the coordinates placed the site somewhere in the correct watershed. 3.1.1 Metadata Validation: Drainage Areas • • • • rigorous determination of drainage areas requires reasonably precise gauge coordinates and rigorous delineation of watershed boundaries this was not possible for the present exercise which focused on discharge data many of the drainage areas given in UNESCO sources are likely wrong, particularly for streams in arid regions where the delineation of desert watershed boundaries always poses difficulties when using these data for sensitive calculations, the drainage areas for these gauges should be corroborated if appropriate software [GIS & related watershed delineation and area calculation routines] and digital geographic data including Digital Elevation Models [DEMs] and river channel networks are available • for present purposes drainage areas were selected according to comparisons with alternative estimates where available • for some jurisdictions, the UNESCO gauge areas could be replaced directly with data from national gauge catalogues or inventories these include: USA, Canada, Australia, UK, Colombia and individual gauges from scattered locations that have been reported in various national sources some published areas may have been changed in the interim by the source agencies • • • • • • • for numerous sites, different drainage areas were given by the UNESCO source files including IHD, WMO, RIV and the GRDC catalogue for many cases, the correct choices were obvious for 62 cases, the correct drainage areas were not obvious for 16 of 62 cases, the differences in potential drainage areas were 10% or more the minimum and maximum drainage areas found in UNESCO sources for the 62 gauges are listed on sheet “areas_1” in spreadsheet unq_cat.xls 3.1.1.1 Drainage Areas Estimates of Fekete et al. and others 29 • • • • • • • • • some recent sources (Fekete et al., 1999; Olivera et al., 1995) estimate drainage areas that are substantially larger than UNESCO figures for some of the gauges considered herein generally, these revised estimates derive from watershed delineations based on 30 minute Digital Elevation Models [DEMs] (e.g., GTOPO30) and in the case of Fekete et al., STN-30p, a simulated topological stream network derived from the 30 minute DEM Fekete et al. acknowledge that their methodology tends to overestimate areas and works best for watersheds >25,000 km2 even for larger watersheds, the methodology of Fekete et al. occasionally produces perceptible discrepancies with other estimates; e.g., for the Rio Grande @ Laredo TX, the STN-30p estimate is 566,451 km2 versus 343,375 km2 (USGS/IBWC) versus 352,178 km2 (UNESCO) Fekete et al. evidently include a large area [200,000–230,000 km2] bounded by the Rio Grande, Colorado and Yaqui watersheds that many consider to be a distinct endorheic unit that does not contribute to the Rio Grande deference is given to the USGS/IBWC estimate for Rio Grande @ Laredo TX for the time being most larger discrepancies between the estimates of Fekete et al. and others similarly involve arid regions where Fekete et al. have included areas of endorheic drainage that contribute so rarely, if at all, that they are normally not considered part of the designated drainage basin the issue is not strictly of right or wrong basin delineation, but what estimates are more practically useful if an endorheic system only spills into an adjacent basin at recurrence intervals of 100 years or more, it makes little practical sense to include the area with the adjacent system; however, it is not clear how frequently a normally closed system must contribute to a watershed before it is meaningful to include the area with the receiving basin • under the circumstances, most of the UNESCO figures may still be reasonable estimates of the drainage areas that contribute most of the time, while the DEM-based estimates include greater areas that contribute runoff only rarely • accordingly, UNESCO figures were changed only where there was good reason to believe that these represented typographical errors or significantly underestimated the drainage areas active much of the time • there are 363 sites in the present set that have drainage areas estimated by Fekete et al. from their STN-30p DEM these are listed on sheet “Fekete_areas” in inventory file “unq_cat.xls” some of these areas were used either where gauges had no available drainage area in other sources, or the available sources were obviously wrong • • 30 3.1.1.2 Drainage Areas Estimation: Technical Issues • the reliability of drainage area estimates depends on several factors including: 1. the reliability of the available gauge coordinates; many gauge coordinates specified in available international compilations are inaccurate and in some cases, drainage areas have likely been calculated for incorrect gauge locations 2. assuming that the DEM is correct, there will be discretization errors that increase in percentage terms as drainage areas decrease; higher resolution DEMs give better results — the most recent estimates are being developed from the Hydro1K DEM 3. currently available global DEMs have errors over broad regions of the world where currently available elevation data sources are less reliable; these would affect drainage area delineations 4. in a few cases, perceptibly different drainage areas have been obtained for the same DEM and watershed boundary files; differences are apparently due to alternative watershed delineation and area calculation software; this suggests that some software routines may not correctly account for different map projections or have other bugs 3.2 Data Validation Without out ready access to “official” national source agency data files except for the USA, data quality was assessed by the joint application of statistical methods and cross-referencing of multiple versions of records. Data quality evaluation methods included: • Scans for replicated sequences that identified same-site and geographical replicates including time-shifted sequences of 6 months or more. Examining the replicates lead to the correction of numerous geographical and temporal errors. • Cross-comparisons amongst available alternative records were run to identify remaining differences. Analysis of the latter turned up further replicates and timeshifts of 1–5 months, and many obvious typos and other errata. • For 200+ gauges, 2-6 alternate versions were available for nominally the same sites. These invariably differed on at least a few data, and often on lengthy sequences. Most discrepancies are small enough to ignore, e.g., differences that may have arisen between alternative series containing provisional, final, or revised 31 data releases by the source agency, or by crude unit conversion, crude rounding or other low-precision data manipulation. Large discrepancies were resolved mostly by accepting the alternate data closest to the pattern shown by nearest neighbour gauges, or if no near neighbours were available, the expected seasonal norms at the site under investigation. For some smaller watersheds, rain gauge data were also used to verify questionable stream records. 3.3 General Results for WMO/UNESCO Data Sets For allegedly vetted and openly published data sets, the WMO and RIV compilations contain surprising numbers of discrepancies in both the gauge metadata and the discharge series. Generally, discrepancies were: 1. common to both WMO and RIV indicating common errors in common source files, or 2. unique to either WMO or RIV indicating errors that were introduced either (A) from the use of different source files, or (B) by the respective human compilers during data entry or transfer. Judging from the ubiquitous presence of typographical errors (simply “typos” herein), it seems likely that most data in these compilations were entered manually without rigorous data QC/QA protocols to ferret out errors. Errors were found in all sources including a few in data and metadata obtained from leading national agencies such as the USGS. Data in compilations and from repositories such as GRDC and MED-HYCOS one step or more removed from source agencies had perceptibly more errors. Contrasted over a common subset of site records, discrepancies in RIV exceeded those in WMO by more than 2 to 1. These remarks are not intended to blame the personnel involved. The problems stem from blasé attitudes at higher levels. Had the sponsoring agencies demanded strict data QC/QA and allocated appropriate resources, the compilers of these international data sets would most likely have generated much cleaner products. Data quality problems with discharge records included: • • • • • replicated sequences, time-shifted sequences, usually where data were submitted on some national “water year” basis that differs from calendar years, or where some records were replicated or deleted during processing thus shifting the remaining data forward or backward in time, geographical replication, i.e., records containing fragments from other gauges, geographically mis-located data, i.e., complete or partial records given at the wrong location (not otherwise replicated), sporadic typos and other isolated errata. 32 Many of these problems were corrected. For numerous unresolvable cases, data from one of the competing alternatives were arbitrarily retained with warnings that the choices may have been wrong. In a few cases, data were deleted because all available alternatives seemed dubious. Undoubtedly errors remain in the present final data set; however, the final data set is generally much cleaner than the main sources (WMO and RIV). Without going to the national source agencies, there is no way to resolve the lingering issues. For anyone who desires an exact comparison, the best way is to obtain WMO and RIV, and to run them off against each other and the present data set. 3.3.1 Data Set Summary Statistics The final data set has 970 gauge records. The gross total number of records (station years) in the set is 28,207 yrs, representing about 27,193.4 net years (total months divided by 12) of data. Average record length is about 28.0 net years. After discounting records that might be composited because of geographical proximity, the number of geographically distinct “operational gauges” would be 950 or less with longer average record length. As the table below shows, almost 20% of records have less than five years of data, and 34% have less than 10 years. However, even these short records can be helpful when no other data are available. † sites % y<5 5 ≤ y <10 10 ≤ y <25 25 ≤ y <50 50 ≤ y <100 100 ≤ y 175 157 259 185 174 20 18 16 27 19 18 2 Total 970 100 net yrs † net years = total months / 12 3.4 Technical Notes 3.4.1 Site Numbering Scheme 33 While sites in RIV are numbered, the WMO set did not have site codes. For programming and sorting purposes, non-FSU sites in the WMO file were numbered in the order found beginning from 9001. The resulting file had 878 sites; hence, the last site has number 9878. The continuation of these numbers is the basis for the scheme in the final data set. Additional records that were only available in RIV were assigned numbers of 9879 or higher. Some sites were added and later deleted, and some numbers were recycled; hence, the number of the last gauge is greater than the number of sites. This site numbering system is purely arbitrary and can be easily changed. Sites are listed by these code numbers in the accompanying spread sheet “unq_cat.xls”. 3.4.2 Country and Continent/Region Codes To facilitate organizing the data sets and summarizing site lists, two-letter codes for (1) country or territory, and (2) continent or region were specified. Country codes found in the spreadsheet catalogue file and the gauge identification headers used herein are the ISO 3166-1 standard familiar to many as the internet country / territory codes (ISO, 2001). The complete set as given early 2001 is listed in the site catalogue spreadsheet “unq_cat.xls” on sheet “ISO_Country_codes”. The country code for Congo (formerly Zaire) has been changed to CD from ZR used previously. Although the current ISO code for United Kingdom is GB, the code UK has been retained because UK appears to be the more widely used of the two [e.g., all UK government www sites are .uk]. The continent and region codes used here are listed below. These are arbitrary creations for my convenience. Others could be easily substituted. Table 3. Continent / region codes. Continent / region Africa Code Continent / region Code AF Europe AM Indian Ocean Asia AS North America Australia AU Pacific Ocean d PO Central America CA South America SA Caribbean CB Middle East a 34 EU b IO c NA a once called “Asia Minor”, more recently “West Asia” in some United Nations publications; includes Turkey, Jordan, Israel, Cyprus, Syria, Iraq b Mauritius, Comoros, Seychelles, Reunion, Maldives, and other islands c d Canada, US, Mexico often called “Oceania”; includes New Zealand, Papua New Guinea, New Caledonia, French Polynesia, American Samoa, Guam, Micronesia, Palau, Hawaii 3.4.3 Note on Replicates In general, replication and time-shifting errors are not likely major problems with the source agencies of most developed and many developing countries. However, in my experience, nearly all international compilations of hydrometric and environmental data have been plagued with these kinds of bookkeeping errors. Inadequate or non-existent QC/QA protocols for data entry and inept data base programming seem to be the root causes. Evidently, few, if any, data compilers (i.e., humans) check for these kinds of errors. Using the US data [USGS HCDN and US96 data sets; see Section 16] as test cases, scans suggest that the empirical probability of a 12 month discharge sequence being replicated naturally is essentially 0 excluding trivial cases of records having numerous 0 discharges or data given to only single digit precision. Even for 6 month sequences or 6 of 12 months in a standard calendar year, the chance of natural replication of non-zero discharges is practically nil. 3.4.4 Note on Statistical Methods — Inter-record Calibration and Adjustment When concurrent data series such as WMO and RIV differ somewhat, it was necessary to choose one version over the other for the final data set, and often to fill missing values in the chosen series by estimating a discharge from data in the rejected series. For example, when WMO and RIV versions differed by some perceptible systematic effect and WMO was chosen for the final set but had some missing entries that were available in RIV, conversion relations from one series to the other were developed by statistical methods applied to concurrent data and the missing entries were estimated. The alternate versions of discharge records usually represent different data releases with the later releases often containing retrospective corrections of systematic biases present in earlier versions. Agencies may make such corrections at any time that errors are uncovered. The RIV versions of many records have data submitted to UNESCO 25+ years ago, while many records in WMO seem to have been more recently obtained by retrieval of entire historical records; hence, it is not surprising that two respective versions often differ. 35 For some west African countries, multiple versions of discharge records exist that differ by what seem to be systematic adjustments of all or part of the historical records according to the views of the analysts compiling the particular versions of the series. Generally, the competing versions of the data series exhibit systematic interrelationships; hence, the principles involved are the same. When alternate versions of discharge records differ by systematic adjustments, the concurrent data in the two alternate versions will often show strong statistical relationships that permit the adjustment of one version to approximate equivalence with the other. Effectively, this amounts to a statistical proxy for the corrections applied by the agencies generally at the base level at which water level traces are digitized and converted to discharge rates. When alternate versions of the nominally same discharge record differ and concurrent data do not show systematic relationships, there may be more serious problems present in one or the other of the alternate versions. Most cases encountered in the present data sets were governed by simple linear relations, or relations that were linear on subsets of the data. Most often the subsets were either multi-year temporal blocks or discharge ranges. In at least one case, the inter-relations between alternate concurrent data seemed to be governed by monthly or other seasonal aggregates of the data. Ordinary least squares [OLS] regression, which requires that the independent predictor variable be perfectly known, does not generally apply in these cases because both the dependent and predictor variables contain measurement or estimation errors. Under certain conditions, the presence of these measurement errors in the predictor variable can lead to significant bias in the equations fitted by OLS. Broadly, the fitting problem, which is a simple kind of uncontrolled calibration, falls into two classes: 1. When the variability the dependent variable is high relative to the range of the independent variable, OLS gives a slope coefficient that is too low and a constant that is too high. Consequently, for high values of the independent variable, the dependent variable is under-predicted, and vice versa for low values of the independent variable. When these conditions prevail, the estimation errors produced by OLS equations can be quite high. The simplest technique for these cases is geometric mean [GM] regression which applies to simple linear cases with only a single predictor variable. 2. When the variability the dependent variable is low relative to the range of the independent variable, OLS methods can give good results for linear and curvilinear relations. These conditions often apply to the data considered herein. For example, when WMO and RIV differ by some small systematic effect and the noise component is small, the data typically plot approximately along a straight or 36 curved line with little scatter. In these cases, linear and polynomial equations fit by OLS (called “rough calibration” herein) are adequate. These techniques were applied to estimate missing data or adjust time series in a relatively small number of cases involving mainly west African discharge records. Most of these cases were amenable to quick, rough calibration methods, but a few required GM regression. The methods were used in other cases to assist in the identification of aberrant data. 3.4.5 Note on Statistical Methods — Average Percent Difference The average percent difference is a crude measure used herein for roughly gauging the extent of differences between two quantities X and Y. It is calculated as: % dif = (X −Y) × 200 (X +Y) If abs(%dif) ≥ 25, the disparity between X and Y merits attention. If 10 ≤ abs(%dif) < 25, the difference is potentially significant. As X and Y approach 0, %dif tends to blow-up and these rules breakdown; nonetheless, %dif adequately characterizes discrepancies between alternate discharges for all but low-discharge situations. 3.4.4 Note on Composited Records • • • • • • composites are a kind pseudo record involving gauges from 2 or more locations generally in close proximity usually, composites combine records from an older discontinued gauge with a newer active gauge there is nothing wrong with constructing composites for operational purposes; however, composites should be clearly identified the best policy is to main a master data base with the actual gauge records, and a separate operational data base with composites and other artificial constructs this avoids confusion and simplifies validation of master records against source agency files which generally contain actual gauge records RIV particularly, but other sources also, contain composite records that have not been clearly identified 37 • with two exceptions noted below, the known composites were restored to original gauge records as best as could be determined from available information • two US records: Pecos River @ Shumla and Pecos River @ Langtry were composited because the areal difference between the old [Shumla] and new [Langtry] gauges is negligibly small such that the records can be spliced without adjustment • two Brazilian records: Parnaiba @ Porto Famoso and Parnaiba @ Luzilandia were composited because the old and gauge new sites are so close that site coordinates are virtually identical, and there are no overlapping data, i.e., the two records can be separated clearly from the composite — see notes for Brazil • • users can construct other composites according to their preferences all the composites found in UNESCO files were spliced records with no adjustments; however, in several cases, the contributing gauges were far enough apart that adjustments to discharges such as areal pro-rating would be advised. 4.0 RIVDIS Preliminaries • • this section points out some particular problems that should be addressed during preliminary processing of the RIV data set the notes in Part II elaborate many other problems that could also be addressed during initial data processing; hence, anyone choosing to work with RIV is advised to read the annotations carefully and compile a greater list 4.1 RIV1 or RIV2 RIVDIS (RIV hereafter) comes in two slightly different versions: A. RIV1 — from UNH B. RIV2 — from ORNL Judging from the discrepancies itemized in the following sections, RIV2 is the most recent version, while RIV1 is an earlier one with some minor problems not in RIV2. Be warned. Neither RIV1 nor RIV2 come in particularly user friendly formats. Obvious junk was identified and cleaned up before going on to the main crosscomparison with WMO. Some items are listed below in the order in which they were encountered. Numerous other problems with RIV source files that could be cleaned up 38 in preliminary processing are identified in subsequent sections. Anyone wishing to work with the RIV source files, should read this entire document carefully and compile a list of particular items that can be cleaned up during preliminary processing. R32 Lobaye @ M'bata • in RIV1, records for 1969–75 of site 32 are replicated at the end of the first 28 years of record spanning 1951–87 (1976-85 are missing) — this might screw up some data reading algorithms R1474 Aouk @ Golongoso WMO # CF AF • • RIV # River Gauge 1474 Aouk Golongoso 9941 RIV1 has a second record for 1966 RIV2 is assumed here to be correct J F M A M J J A S O N D RIV2 1474 1966 46.1 36.2 12.9 10.0 10.0 10.5 13.8 40.5 RIV1 RIV1 1474 1966 1474 1966 46.1 83.8 16.5 36.2 11.3 12.9 10.0 10.0 11.0 10.0 12.8 10.5 20.4 13.8 40.5 71.0 115.0 169.0 151.0 - 191.0 - 71.0 115.0 169.0 151.0 4.2 Redundant and other Junk Sites The sites listed below can be eliminated from the RIV catalogue and data file. Data are either replicates or can be condensed into a single record. The blue highlighted lines show the catalogue entries that were eliminated. The yellow highlighted lines show the final catalogue entries. • • • R24 and 25 are mixes of crudely rounded and more precise data in places R24 is better than R25, and vice versa W9051 has the best of these two, and was substituted • • • Rio Juramento and Rio Pasaje are alternate names for the same river the spliced record of R495/501 is virtually identical to W944 see discussion further on about potential problems with the last years of this record Table 4.1 Redundant records in RIV 39 WMO # NE AF NE AF NE AF 9051 UY SA UY SA UY SA 9431 CA NA CA NA CA NA 9465 AR SA AR SA AR SA 9444 CA NA CA NA CA NA 9526 RIV # River Gauge Lat Lon El Area 24 25 Goulbi de Maradi Goulbi de Maradi Madarounfa Madarounfa 13.42 19.00 7.19 -99 7.00 -99 -9 -9 25 Goulbi de Maradi Madarounfa 13.32 7.17 355 5,400 511 1129 Uruguay Uruguay Salto Puerto Salto -31.36 -57.93 6 244,000 -32.42 -58.20 -99 -9 1129 Uruguay Salto -31.40 -57.96 309 1173 Rupert De Rupert Nemiscau Nemiscau 52.45 -76.88 211 51.45 -76.87 211 40,700 40,900 1173 Rupert en aval du Lac Nemiscau 51.45 -76.87 211 40,900 495 501 Juramento Pasaje Miraflores Miraflores -25.36 -64.83 610 -25.26 -64.36 610 34,500 34,500 501 Pasaje Miraflores -25.37 -64.83 610 34,500 274 275 Columbia Columbia (On Columbia) International Boundary 49.18 -117.71 410 88,000 48.92 -117.63 400 155,000 275 Columbia International Boundary 49.00 -117.63 400 155,000 6 244,000 The two junk sites below were eliminated. IN AS SV CA RIV # River Gauge 1433 1331 Cauvery Grande de San Miguel Grand Anicut (North) Las Conchas • site 1433, ostensibly for somewhere on the Cauvery River, is entirely a composite of data for two other gauges that appear to be the correct locations for those data – see discussion on Cauvery River further below • site 1331, ostensibly for Rio Grande de San Miguel @ Las Conchas is a muddle of data from two different locations, one legitimate (R1067) and the other unknown — see discussion further below on Rio Grande de San Miguel 4.2 Replicated Records 40 R864 Ganges @ Paksey RIV # BD AS IN AS 864 863 River Gauge Ganges Ganges Paksey Farakka • 1965–68 data at site 864 are for site 863 Ganges @ Farakka, India • see later discussion of Ganges about the difference between these two sites Niger @ Niamey and Gaya NE AF NE AF • RIV # River Gauge 15 1513 Niger Niger Niamey Gaya the replicate scan finds two repeated 6 month runs at these sites, but these are part of a greater confusing muddle at several Niger gauges (Niamey, Malanville, and Gaya) — see Niger River section later in report 4.2 Other Preliminary RIV Fixes R1461 Mekong Nakhon Phanom TH AS RIV # River Gauge 1461 Mekong Nakhon Phanom • R1461 must be multiplied by 10 to get the correct order of magnitude • • metadata (blue highlight) in the RIV site catalogue for R1461 are wrong the correct data are given below (yellow highlight) WMO # RIV # River Gauge Lat 9343 1461 1461 Mekong Mekong Nakhon Pathom Nakhon Phanom Lon Area 13.93 99.74 17.40 104.80 373,000 R1462 Madelena @ Madelena WMO # RIV # PO ST AF • • 1462 9167 River Gauge Madelena Agua Palite Madelena Madalena Azores Sao Tome & Principe strangely, RIV compilers identified this site as belonging in the Azores, and even more strangely, classified the Azores as being in the Pacific Ocean (despite giving approximately correct location coordinates for the Azores in the eastern Atlantic). the correct name and location of R1462 is that of W9167 41 Iraq and Costa Rica — Time-shifted Records WMO # RIV # IQ IQ IQ IQ AM AM AM AM 9212 9213 9214 9215 812 813 811 1243 CR CR CR CR CR CA CA CA CA CA 9683 9684 9685 9686 9682 331 329 235 237 330 • • • River Gauge Tigris Tigris Euphrates Euphrates Mosul (Al Mawsil) Baghdad d/s Hit d/s Hindiya barrage Grande de Terraba Grande de Tarcoles Sarapiqui Barranca Reventazon Palmar Balsa Cariblanco Nagatac Angostura Iraqi and Costa Rican records in RIV and IHD are on local “water years” WMO has the correct calendar year basis —a note appended to the WMO file indicates that the same problem had existed in an earlier release, but had been fixed it’s much easier to take the data from the present set for the corresponding WMO sites than trying to sort this out from RIV alone 5.0 WMO Preliminaries • • this section points out some particular problems that should be addressed during preliminary processing of the WMO data set the notes in Part II elaborate many other problems that could also be addressed during initial data processing; hence, anyone choosing to work with WMO is advised to read the annotations carefully and compile a greater list 5.1 Replicated Data W9739 Danube @ Bezdan (Serbia) • 1980 was entered twice identically; one copy was deleted W9848 Po @ Pontelagoscuro 42 • 1931 was entered twice identically; one copy was deleted W9850 Adige @ Boara Pisani WMO # RIV # River Gauge 9850 Adige Boara Pisani IT EU • • • there are 2 entries for 1973 the first 1973 record is not in R201 it is a copy of 1976; it was deleted 1973 1973 1974 1975 1976 201 J F M A M J J A S O N D 104.0 112.0 104.0 93.5 104.0 100.0 109.0 116.0 97.7 100.0 91.0 102.0 144.0 102.0 91.0 94.5 96.5 152.0 215.0 94.5 103.0 164.0 194.0 386.0 103.0 90.5 180.0 225.0 424.0 90.5 96.5 167.0 217.0 373.0 96.5 89.5 104.0 126.0 217.0 89.5 295.0 157.0 161.0 251.0 295.0 439.0 247.0 138.0 180.0 439.0 395.0 144.0 110.0 132.0 395.0 165.0 106.0 100.0 126.0 165.0 W9877 Danube @ Orsova (1971:Drobata-Turnu Severin) • 1980 was entered twice identically; one copy was deleted W9799 Loire @ Montjean FR EU WMO # RIV # River Gauge 9799 Loire Montjean 737 • in W9799, 1896 is replicated in 1897, 1897 data are shifted forward to 1898, and the 1898 data are lost • IHD and R737 appear to have the correct data J F M A M J J A S O N D 9799 9799 9799 9799 1896 1897 1898 1899 1130 1130 1400 1240 470 470 2870 815 700 700 2070 374 655 655 2180 396 295 295 685 477 278 278 595 267 175 175 392 444 440 440 267 130 260 260 675 108 945 945 495 159 1990 1990 274 251 1870 1870 460 195 737 737 737 737 1896 1897 1898 1899 1130 1400 460 1240 470 2870 525 815 700 2070 685 374 655 2180 635 396 295 685 840 477 278 595 705 267 175 392 333 444 440 267 135 130 260 675 96 108 945 495 139 159 1990 274 246 251 1870 460 330 195 Niger River @ Niamey and Gaya WMO # RIV # River Gauge 43 NE AF NE AF • 9053 9052 15 1513 Niger Niger Niamey Gaya the replicate scan finds two repeated 6 month runs at these sites, but these are part of greater confusing muddle at several Niger gauges (Niamey, Malanville, and Gaya) — see Niger River section later in report W9446 Colorado @ Buta Ranquil AR SA • • WMO # RIV # River Gauge 9446 Colorado Buta Ranquil 480 WMO file has a second pair of 1979–1980 data at the end of record 9446 the second 1979-80 data are not from site 9446 and were deleted 5.2 Other WMO Fixes Replicated Sites MA AF MA AF WMO # RIV # River Gauge 9187 9188 1440 68 Ouergha Sebou Ourtzagh Azib Soltane • • • • both sites appear twice in WMO the first instances are short records spanning 1969–75 the second instances span long periods (1951-89; 1959-89 respectively) the short record segments differ slightly from the same years appearing in the longer WMO records, but are identical to the same years appearing in the RIV versions • the composites that matched the RIV versions were retained Mekong River Gauges – Thailand TH AS TH AS TH AS • WMO # RIV # River Gauge 9340 9342 9343 1248 891 1461 Mekong Mekong Mekong Mukdahan Chiang Saen Nakhon Phanom records for the 3 Thai Mekong gauges in WMO must multiplied by 10 to bring them to the correct scale 44 Part II: Annotations for Monthly Discharge Data by Continent/Region and Country Most of the annotations that follow are organized by continent / region and country. Two subsets of records are discussed in separate sections; a) US data in Section 16 b) mid-basin Niger River gauges in Section 17 6.0 Africa Africa: Benin Mekrou @ Barou BJ AF • • • WMO # RIV # River Gauge 9935 1465 Mekrou Barou according to OHRAOC, there are two gauges: one operated by Niger which they call “Mekrou @ Barou”, and another operated by Benin which they call “Mekrou @ Barou aval” OHRAOC lists the same location coordinates and drainage area for both the presence of alternate records from two distinct gauges may partly explain some of the differences between alternate versions of this record • • IHD and RIV have 1961–1978 GRDC gives annual averages and extrema for the same period • for concurrent months, the GRDC data are 1-2% lower than RIV, and data fall along a straight line on the calibration plot two months from the GRDC summary were added to RIV after a slight adjustment • • • • IHD has data for 9 months in 1965 that are not in RIV these cannot be corroborated presently, but are typical for this gauge the differences between IHD and RIV for Jul–Sep 1965 are also typical of the minor discrepancies between the two versions IHD RIV • 1965 1965 J F M A M J J A S O N D 0 - 0 - 0 - 0 - 0 - 3 - 7 6 36 34 147 146 46 - 13 - 4 - the joint RIV / IHD set was retained with Jan–Jun and Oct–Dec 1965 taken from IHD 45 Mono @ Athieme — Warning GRDC muddle BJ AF TG AF • WMO # RIV # River Gauge Area 9934 9068 1464 18 Mono Mono Athieme Kolokope (Correkope, Dotekope ?) 21,475 9,900 • R1464 and an independent source give nearly identical data for 1944–1984 [ca. 27 net years due to many missing months] GRDC summary data span 1952–1992 [ca. 30 net yrs] for ostensibly the same site • as per the plot below, GRDC annual averages are about 1/2 those given by R1464 250 mean discharge cms Mean Annual Discharge: Mono @ Athieme 200 150 100 50 0 1951 1953 1955 1957 1959 1961 1963 1965 1967 1969 1971 1973 1975 1977 1979 1981 1983 1991 GRDC RIV • the two scatterplots below show that RIV data for Athieme are much more closely related to concurrent data for the upstream gauge at Kolokope than to the Athieme data given by GRDC [see Mono @ Kolokope, Togo for note on the gauge name and other metadata] • it seems likely that GRDC have muddled the data for Athieme with another gauge from the area • R1464 is retained 46 600 500 RIV cms 400 300 200 Mono @ Athieme Scatterplot: RIV versus GRDC 100 0 0 100 200 300 400 500 600 700 800 900 GRDC cms 1000 900 800 Athieme 700 600 500 400 300 Mono River Scatterplot: Athieme versus Kolokope (Correkope ?) 200 100 0 0 100 200 300 400 500 Kolokope (Correkope ?) Ouémé @ Bonou BJ AF • • • • WMO # RIV # River Gauge 9936 1468 Oueme Bonou R1468 has 1948–1984 with numerous missing months GRDC gives annual averages and extrema for the same period GRDC averages are 1-2% lower and maxima ca. 3% lower than R1468 concurrent R1468 and GRDC data fall along a straight calibration line 47 600 • • GRDC summary data have 6 months not in R1468 these were added to R1468 after a slight upward calibration adjustment Africa: Burkina Faso Black Volta @ Dapola BF AF WMO # RIV # River Gauge 9984 1543 Black Volta Dapola • • R1543, an independent source (IND) and GRDC summary data span 1951–1989 these agree generally except for several errata in R1543 and a few in GRDC • RIV has several typos • • for Aug 1967, R1543 discharge = 0.34 IND and GRDC gives 348 which is about what is expected for a high season discharge • • for Jul 1982, R1543 discharge = 28 IND gives 58 and which makes the annual average identical to GRDC • • • • • for Oct 1986, R1543 discharge = 6,140 GRDC gives 0 IND reports a missing value discharge should lie between the preceding and following months (421 and 43 m3/s) Oct 1986 was set to missing • in R1543, in 1984, the Jul discharge appears to have been entered twice pushing Aug–Nov discharges ahead 1 month as determined from GRDC by subtraction, Dec discharge must be 0, or some fractional value <1; a 0 was assumed for present purposes • 1984 1984 1984 1984 1984 1984 1984 1984 1984 1984 1984 1984 1 2 3 4 5 6 7 8 9 10 11 12 IND R1543 0.0 0.0 0.0 0.0 37.2 54.2 50.1 64.0 83.1 35.7 2.4 1.7 0.0 0.0 0.0 0.0 37.0 54.2 50.0 50.1 64.0 83.1 35.7 2.4 48 • • • • for Sep 1988, GRDC gives 586 R1543 and IND give 286 R1543/IND appear to be correct whenever Sep discharges have exceeded 500 m3/s, the Oct discharges have always been well above the 111 m3/s reported for 1988 Africa: Cameroon Cameroon: General Remarks • • • six gauges have two, sometimes three, versions that differ perceptibly over certain periods it is unclear which version is more recent or more valid; hence, the choice amongst alternatives is arbitrary the WMO versions [with a few typos corrected] were arbitrarily accepted for the present set Benoue @ Garoua WMO # CM AF • • 9080 RIV # 31 River Gauge Benoue Garoua together the UNESCO sources give 1930–1980 with numerous missing months before 1949 W9080 is the most complete record • IHD and R31 are similar on concurrent months, but have some perceptible disagreements • • W9080 has persistent discrepancies with IHD/RIV over the concurrent 30 years from ca. 1950–1980 the differences are not systematic in any obvious way • RIV has several significant errata listed below 1950 4 1950 12 1955 6 1963 8 1973 11 1977 5 • WMO RIV dif seasonal 1.0 74.8 95.9 724.0 58.2 10.0 9.0 179.0 1.0 1770.0 570.0 0.2 -8.0 -104.2 94.9 -1046.0 -511.8 9.8 1.8 49.3 65.0 1074.6 154.5 10.1 W9080 is retained, but the choice is arbitrary 49 Dja @ Somalomo WMO # CM AF • • 9087 RIV # 7 River Gauge Dja Somalomo W9087 May 73 discharge of 3.45 is an error R7 May 1973 discharge of 62.5 m3/s looks correct Mbam @ Goura WMO # CM AF 9082 RIV # 28 River Gauge Mbam Goura • UNESCO sources have Apr 1951 – Mar 1980 • there is a distinct block from Apr 1970 – Dec 1975 when R28 data are systematically higher than W9082 on an annualized basis, R28 has mean discharge 602 m3/s versus 581 m3/s for W9082 during this period • • except for two large discrepancies, the relationship between the two alternate data series could be characterized by the linear equation W9082 = -4.012 + 0.988 * R28 • the two large discrepancies are listed below 1972 7 1975 6 wmo riv 477 225 844 533 dif seasonal -367 -308 845 484 • • R28 data are closer to seasonal norms, but W9082 data are plausible contrast against other Cameroon data give no clear indications as to which alternatives are more correct • W9082 is arbitrarily accepted for the present set Noun @ Bafoussam / Nkam @ Melong WMO # CM AF CM AF 9081 9085 RIV # River Gauge 749 20 Noun Nkam Bafoussam Melong 50 • RIV gives data for Jan 1976–Mar 1977 for Noun @ Bafoussam that are identical to data given for Nkam @ Melong by WMO and other sources • the record given by WMO and an independent source for Noun @ Bafoussam end in 1975 • the discharge patterns at three nearest neighbours indicate that the Jan 1976–Mar 1977 given by R749 for Noun @ Bafoussam almost certainly belong correctly to Nkam @ Melong Sanaga @ Edea WMO # CM AF 9079 RIV # 27 River Gauge Sanaga Edea • • WMO and RIV span 1943–1980; IHD has 1943–1972 except for a few typos, RIV and IHD are identical • • WMO and RIV disagree persistently from 1948–1975 WMO is mostly lower than WMO by < 10% except for a few extremes • Dec 1949 - Feb 1959 is a distinct block where the WMO data are systematically lower than R27 data • • • three large discrepancies are shown below for Jul 1950, it is unclear which is more correct for Dec 1953 and Oct 1975, the R27 data are more likely to be in error 1950 7 1953 12 1975 10 • R27 W9079 dif seasonal 2060 2290 1564 2990 1220 5032 -930 1070 -3468 1928 1358 5440 WMO was accepted on the possibility that it represents a more recent retrieval of historical data that have been revised since the UNESCO release in 1972 Sanaga @ Nachtigal WMO # CM AF 9088 RIV # 29 River Gauge Sanaga Nachtigal • • UNESCO files and an independent source (IND) have Apr 1951 – Mar 1980 all agree to 1972 • WMO and RIV have minor disagreements after 1972 51 • IND has larger discrepancies with the other two after 1972 • • Sep 1975 W9088 discharge = 1,887 is likely a typo R29 and IND give 2,180 • again the choice is unclear; WMO was accepted arbitrarily for the present set Wouri @ Yabassi WMO # CM AF • RIV # 9086 26 River Gauge Wouri Yabassi • from Nov 1973 – Jul 1975, W9086 discharges below 300 m3/s are systematically and perceptibly (by 20 m3/s) lower than R26 discharges WMO was retained, but some may prefer the R26 record Africa: Central African Republic Aouk @ Golongoso WMO # CF AF RIV # River Gauge 1474 Aouk Golongoso 9941 • • • for Aug 1961, and independent source (IND) and GRDC give 78 R9941 gives 48 IND/GRDC discharge of 78 is accepted • R9941 seems to have compressed 1966 and 1967 into a single 1966 record and dropped 1967 IND and GRDC consistently give 1966 and 1967 as below IND is accepted • • J F M A M J J A 9941 1966 46.1 36.2 12.9 10.0 10.0 IND 1966 46.1 16.5 11.3 10.0 11.0 10.5 12.8 13.8 20.4 40.5 40.5 IND 1967 83.8 36.2 12.9 10.0 10.0 10.5 13.8 - Chinko @ Rafai CF AF WMO # RIV # River Gauge 9937 1470 Chinko Rafai 52 S D mean 71.0 115.0 169.0 151.0 71.0 115.0 169.0 151.0 57.2 56.2 191.0 O - N - - 46.0 • • R1470, an independent source (IND) , and GRDC annual summary data span 1952–1973 these are almost identical except for a few errata in R1470 • • • R1470 has a time shift error in 1967 Feb–Apr are back-shifted one month GRDC and IND appear to have the correct chronology R1470 1967 IND 1967 GRDC 1967 • • • • J F M A M J J A S O N D 134 134 134 58 - 46 58 - 115 46 46 115 - - - - - - - - there is a discrepancy between IND/GRDC and R1470 in Nov 1971 R1470 discharge = 524 both IND and GRDC give 241 data at nearest neighbour, Mbomou @ Zemio suggests that R1470 is more likely to be correct Lobaye @ M'bata WMO # CF AF • RIV # 9148 32 River Gauge Lobaye M'bata Sep 1968 R32 is 505 not 205 M'Bomou @ Zemio CF AF WMO # RIV # River Gauge 9938 1471 M'Bomou Zemio • • R1471 and an independent source (IND) span 1952–1988 GRDC annual summary data span 1952–1994 • these are almost identical except for a significant decimal shift typo in IND and GRDC for Jul 1954, these have discharge = 2,220 R1471 has 222 which is expected in the available historical record, the maximum Jul discharge was 543; hence, 2,220 is implausible • • • 53 Oubangui @ Bangui WMO # CF AF 9013 RIV # 10 River Gauge Oubangui Bangui • • • • • the available data sets all begin in 1911 and are missing 1921–34 IHD runs to 1972 W9013 runs to 1975 an independent set (IND) runs to 1975 and has some short fragments in the 1980s R10 runs to 1990 • • when they overlap, IHD, W9012 and IND are virtually identical unlike most other cases, R10 is not identical to IHD (and the others), and seems to be the most modern series • the relationship between R10 and the others is somewhat unstable as shown below 54 150 125 mean annual difference 100 m3/s 75 50 25 0 -25 -50 1910 1920 1930 1940 1950 1960 1970 1980 1970 1980 150 125 smoothed mean annual difference 100 m3/s 75 50 25 0 -25 -50 1910 • • 1920 1930 1940 1950 1960 the raw 12 month running mean difference between W9013 and RIV is very rough due to numerous outliers that are probably typos or other errata the smoothed running mean difference shows that the mean annual discharge of R10 was consistently about 50–60 m3/s greater than the mean annual discharge of W9013 (and the others) from 1911–1960 55 • • • • in 1960, the relationship shifted abruptly; so that, excluding a few outliers, R10 and WMO were near parity through the 1960s from 1970–75 the relationship was erratic, but the R10 annual mean discharge was increasing relative to WMO N.B. some references suggest that there may be two gauges at Bangui, e.g., upstream and downstream, or one operated by Congo (Zaire) records from two distinct gauges and mixed records that may be composites of records from two gauges may explain the apparent discrepancies seen in the available Oubangui @ Bangui data series • R10 being the apparently more modern series was accepted for the present data set to replace W9013 • the x-y scatterplot below shows that, other than for a small scattering of outliers, the are near enough to equality that analyses dependent on average and high discharge properties would not be much affected regardless of which series was used 14000 12000 WMO/GRDC 10000 8000 6000 4000 2000 0 0 2000 4000 6000 8000 10000 12000 14000 RIV • • the scatterplot below shows that the most significant differences are evident in the low discharge range (generally, <3,500 m3/s) sensitive analyses of low discharge phenomena might be affected by which series is chosen 56 3000 2500 RIV 2000 1500 1000 500 0 0 500 1000 1500 2000 2500 3000 WMO Outliers / Typos • • • • • these series have numerous outliers that are likely data entry or transcription typos the main ones are listed below the three large (Class 1 - red shading) typos in R10 were replaced with the expected values obtained by calibration regression relations (for the mid 1960s, the series were at near parity so the W9013 discharge of 1,460 for Apr 4 1964 was substituted directly for the R10 value of 146) the Class 2 outliers (magenta shading) are likely erroneous, but the values were within plausible ranges given the discharges of preceding and following months if these data are indeed in error, the discrepancies are large enough to affect some sensitive statistical work R10 W9013 dif RIV expected value 1 1 1 1 1919 1958 1964 1973 10 10 4 2 5,360 6,400 146 880 8,950 9,380 1,460 333 -3,590 -2,980 -1,314 547 8,965 9,395 1,460 2 2 2 2 2 2 2 2 2 1915 1938 1951 1959 1961 1971 1971 1972 1973 11 5 12 9 8 7 10 11 9 9,610 1,320 4,240 7,860 6,080 2,440 6,960 7,560 5,680 8,580 1,730 4,720 7,620 6,870 2,496 7,067 7,378 5,870 1,030 -410 -480 240 -790 -56 -107 182 -190 8,595 1,898 57 WMO expected value 809 4,220 7,844 6,062 2,745 7,084 7,543 5,888 Ouham @ Bossangoa CF AF WMO # RIV # River Gauge 9940 1473 Ouham Bossangoa • • R1473 and an independent source (IND) span 1951–1988 GRDC annual summary data span 1951–1992 • R1473 has three decimal shift typos • • • for Sep 1951, R1473 discharge = 52 IND gives and the GRDC annual average implies indirectly that this should be 520 the preceding and following months had discharges >500; a discharge of 52 makes no sense • • for Dec 1967, R1473 discharge = 11 IND gives and the GRDC annual average implies indirectly that this should be 111 • • for Nov 1986, R1473 discharge = 14 IND gives and the GRDC annual average implies indirectly that this should be 147 • R1473 was retained with the corrections listed above Sangha @ Salo WMO # CF AF • • RIV # 9149 14 River Gauge Sangha Salo Sep 1957 R14 is 1,520 not 152 Apr 1967 R14 is 307 not 907 Africa: Chad Chari @ Ndjamena (Fort Lamy) WMO # RIV # River Gauge TD AF 9014 38 Chari TD AF TD AF 9946 9944 1480 1478 Chari Logone Lat Lon El Area Ndjamena (Fort Lamy) 12.12 15.03 285 600,000 Bousso Bongor 10.46 16.73 10.27 15.37 325 321 450,000 73,700 58 • • • • • • Apr 1972 discharge = 999 is likely an error the sum of Apr discharges for Chari @ Bousso and Longone @ Bongor = 88 [the Longone joins the Chari just u/s of Ndjamena] the Apr discharge of 999 is also inconsistent with discharges of Mar and May 1972 at Ndjamena this error is present in all versions of Ndjamena discharges Apr is a low discharge month, and the upstream sites are consistent Apr 1972 discharge was changed to 99 which may be in error, but given the discharges at u/s sites, is close to the true value Logone @ Bongor TD AF TD AF WMO # RIV # River Gauge 9944 9949 1478 1483 Logone Logone Bongor Lai Area 72,000 60,320 • R1478 and GRDC annual summary data span 1948–1986 • • • R1478 has a discrepancy in 1965 the value reported for May belongs in Jun this is confirmed by GRDC summary data and the upstream gauge at Lai R1478 1965 GRDC 1965 J F M A M J J A S O N D 128 - 90 90 - - 131 - 131 - - - - - - Logone @ Moundou TD AF WMO # RIV # River Gauge 9947 1481 Logone Moundou • R1481 and GRDC annual summary data span 1935–1985 • • • • R1481 has a discrepancy in Dec 1943 R1481 gives 14 GRDC gives 141 the available data suggest that even in the droughts of the 1970–1980s, Dec discharges did not fall as low as 14 59 Ouham (Sara) @ Moissala TD AF WMO # RIV # River Gauge 9950 1484 Ouham (Sara) Moissala • R1484 and GRDC annual summary data span 1951–1984 • • either R1484 or GRDC are muddled in 1983–1984 R1484 seems to report the same data for Jul–Nov 1984 that GRDC summarizes for 1983, [the mean of Jul–Nov 1984 = 538] J F M A M J J A S O N D GRDC 1983 - - - - - - 211 - 857 - - - 538 5 GRDC 1984 R1478 1984 39 40 - - - - - 211 578 857 765 277 - 39 455 1 6 • • mean mos it is unclear whether GRDC or R1478 has the correct chronology GRDC has been arbitrarily assumed as correct for the present Africa: Congo Foulakary @ Kimpanzou WMO # CG AF • 9024 RIV # 945 River Gauge Foulakary Kimpanzou Dec 1977 W9024 should likely be 175 (as R945) not 62.5 Kouilou @ Sounda WMO # CG AF 9019 RIV # 943 River Gauge Kouilou Sounda • • UNESCO sources has 1969–1982 an independent source (IND) has 1956–1965 plus 1969–1982 • the joint IND/UNESCO set is retained with the warning that the 1956–1965 data could not be corroborated 60 Nkeni @ Gamboma WMO # CG AF 9022 RIV # River Gauge 946 Nkeni Gamboma • • UNESCO sources have 1969–1982 an independent source (IND) has 1956–1965 plus 1969–1982 • the joint IND/UNESCO set is retained with the warning that the 1956–1965 data could not be corroborated Sangha @ Ouesso WMO # CG AF • • • 9020 RIV # 948 River Gauge Sangha Ouesso W9020 and R948 are identical except from Jan 1969 – Dec 1970 when W9020 discharges are modestly (<5%) and systematically lower than R948, but the effect is erratic RIV agrees with the old IHD data, hence WMO is likely the more modern data set WMO was retained Africa: Congo / Congo (Zaire) Congo @ Brazzaville / Congo @ Kinshasa CG AF ZR AF • WMO # RIV # River Gauge 9021 9894 947 1534 Congo Congo Brazzaville Kinshasa the two sites are virtually at the same point on the Congo River Congo @ Kinshasa • • • • • • R1534 records span 1903–1983 an independently obtained data set (IND) of daily discharges spans the same period less 1 month R1534 generally agrees with IND except for minor rounding effects R1534 has ca. 10 significant typos and as many more minor ones scattered across the record these all appear to be data entry errors in R1534 IND was retained 61 Congo @ Brazzaville • • R947 gives a record for Congo @ Brazzaville that spans Jan 1971 – May 1989 IHD and W9021 have subsets of this that are identical to R947 data Africa: Egypt Nile Basin Drainage Area Estimates • discrepancies are evident in available drainage area estimates for the Nile River gauges and total basin WMO # RIV # River Gauge Area UNESCO Fekete et al. SD AF SD AF 9154 9975 Blue Nile Atbara Khartoum Kilo 3 SD AF EG AF EG AF 9155 76 9953 1487 9143 1159 Nile Nile Nile Dongola (Dunqulah) Aswan Dam El Ekhsase Nile basin † † ‡ a FAO 325,000 69,000 275,123 173,580 311,870 221,738 2,694,000 3,612,000 2,900,000 2,694,484 3,588,931 3,746,812 2,846,409 3,000,000 3,826,122 3,109,223 other § 2,200,000 estimate apparently due to GRDC ‡ median of 20 reported estimates from supporting data files for FAO (2001) § World Bank a • • • • the total basin area estimate by Fekete et al. (3,826,122 km2) is the highest of 20 drainage area estimates reported in various sources most sources report the Nile basin area as 2.9–3.1 million km2 the discrepancy is due mainly to the inclusion by Fekete et al. of ca. 800,000 km2 of Egypt’s western desert in the Nile watershed this area receives virtually no rainfall and includes the Toshka depression; hence, it’s inclusion in the Nile watershed is questionable • under the circumstances, the UNESCO estimate of 2.9 million km2 for the drainage area upstream of El Ekhsase [not far above Cairo] is reasonable, but may be low • the drainage areas for Aswan and Dongola (at the upstream end of Lake Nasser behind the Aswan high dam) should be recalculated from a high resolution DEM the World Bank estimate of 2.2 million km2 for Aswan seems low the estimate of 2.7 million km2 for Dongola seems more reasonable • • 62 • FAO’s estimate of 2,846,409 km2 Aswan drainage area seems high if 2.9 million km2 is correct El Ekhsase; however, this is the most reasonable of the available estimates and accepted for the time being Nile @ Aswan AF EG WMO # RIV # River Gauge 9953 1487 Nile Aswan Dam • see previous notes about Aswan drainage area • • R1487, an independent source and GRDC annual summary data span 1869–1984 these all agree except for several errata in RIV and potential error in all versions R1487 Errata — 1877 • • • R1487 has a data entry / time-shift error in 1877 RIV compilers apparently skipped the May entry back-shifting Jul–Dec by one month, and added a spurious entry for Dec that appears to be the next year rather than a discharge general circumstances support the IND/GRDC chronology; historically, Jun discharge never exceeded 2,000 m3/s until the final stages of Aswan High Dam construction in the late 1960s J F M A R1487 1877 1833 1264 IND 1877 1833 1264 GRDC 1877 - 944 944 - 767 767 - M J J A S O N D 972 2639 5899 6442 4704 2851 1818 1878 724 972 2639 5899 6442 4704 2851 1818 724 - 6442 - R1487 Errata — 1892 • Apr 1892 discharge should be 613 not 6113 R1487 Errata — 1907 • Dec 1907 discharge should likely be 1538 not 1583 R1487 Errata — 1958 • • • Aug 1958 discharge should be 9184 not 1866 which is a copy of the Jul discharge the effect on the 1958 annual average is obvious on the plot below between 1936 and 1966, i.e., between completion of renovations to the 1st Aswan Dam and the de-facto beginning of filling operations of the High Dam (official 63 opening was in 1971), mean annual discharges at Dongola in Sudan and Aswan closely tracked each other 4000 3500 cms 3000 2500 2000 Mean annual discharge: Aswan and Dongola, 1950-1970 19 50 19 51 19 52 19 53 19 54 19 55 19 56 19 57 19 58 19 59 19 60 19 61 19 62 19 63 19 64 19 65 19 66 19 67 19 68 19 69 19 70 1500 RIV Aswan GRDC Aswan Dongola R1487 Errata — 1963 • • Oct 1963 discharge should be 4928 not 7928 again, the effect is obvious on the plot above Probable Error 1962 — all versions • • • • • • • from 1936–1966, mean annual discharges at Dongola in Sudan and Aswan closely tracked each other as the plot below shows, Aswan and Dongola annual means were nearly identical with little scatter accepting the Dongola discharge as correct, the 1962 Aswan mean discharge stands out as being 350–360 m3/s (cms) too high if this difference occurred due to an error in one month only, that Aswan monthly discharge would have to be ca. 4,000 m3/s too high looking at the monthly data, the Oct discharge of 9,968, given identically in all available versions, is exceptional; not only is this high, but it would make 1962 the only year between 1936 and 1966 when Oct discharge exceeded Sep discharge furthermore, Oct discharges were typically near the average of Sep and Nov discharges (5,740 for 1962) the predicted annual mean according to the Dongola discharge should be 2816 ± 86 64 • if the Oct discharge is lowered to 5,968, the annual mean of 2,842 falls within the predicted range, and is close to the average of Sep and Nov discharges • thus there is a solid basis for concluding that the Oct 1962 discharge is an error and in the present set was changed to be 5,968 J F M A M J J A S O N D mean R1487 1962 1545 1273 1037 1118 1060 1211 1751 5899 8680 9968 2800 1765 1962 1545 1273 1037 1118 1060 1211 1751 5899 8680 5968 2800 1765 3176 2842 4000 3600 Aswan cms 1962 3200 2800 2400 Mean annual discharge at Aswan versus Dongola, 1936-1966 2000 1600 2000 2400 2800 3200 3600 Dongola cms Nile @ El Ekhsase AF EG • • • • WMO # RIV # River Gauge 9143 1159 Nile el Ekhsase WMO and RIV have 1973–1984 there are small discrepancies between the two on most months of 1976–1979 one exception is Dec 1977 when W9143 gives 985 and RIV gives 1,360 according to the relationship between Dec discharges at El Ekhsase and Asyut upstream, the RIV discharge of 1,360 is most likely correct Nile @ Esna (Isna) EG AF WMO # RIV # River Gauge 9146 1166 Nile Esna (Isna) 65 • WMO and RIV are identical except for small discrepancies and one typo in WMO WMO RIV 1084 1470 1977 11 Nile @ Naga Hammadi EG AF • WMO # RIV # River Gauge 9145 1162 Nile Naga Hammadi R1162 Dec 1975 is 985 not 835 Africa: Ethiopia Blue Nile @ nr Lake Tana ET AF WMO # RIV # River Gauge 9031 Blue Nile (Abbay) nr Lake Tana 11 Area 16,420 • • • formally, the Blue Nile [Abbay in Amharic] begins as the outflow of Lake Tana not far below Lake Tana, the Abbay is joined by the Andasa River at Chara-Chara weirs at Chara-Chara regulate the outflow of both Lake Tana & the Andasa River • the development of the Tis Abbay I and II Hydroelectric Plants [HEPs] Tis Issat Falls has changed the routing of water from Lake Tana about 32 km below Chara-Chara, the Abbay plunges 45 m over Tis Issat Falls the Tis Abbay HEPs are located near Tis Issat falls, but are fed by canals that lead off from the Abbay above the Chara-Chara weirs outflow from the Tis Abbay HEPs rejoins the Abbay Tis Abbay 1 was completed in 1964 Tis Abbay 2 was scheduled for completion in early 2001 • • • • • • • long term mean annual discharge at Chara-Chara is ca. 3.7 km3 from a catchment of ca. 15,300 km2 including ca. 3,600 km2 surface area of Lake Tana long term mean annual discharge at Tis Abbay / Tis Issat is ca. 4.1–4.2 km3 from a catchment of ca. 16,420 km2 [alternately given as 16,300 km2 in another source] • the 1969-1975 (6.7 yrs) record for this gauge has mean annual discharge of 6.1 km3 • for the present, it is assumed that discharge record 9031 represents the combined Abbay discharge below Tis Abbay / Tis Issat 66 • • available records for the Blue Nile are too short and fragmented to ascertain if 1969-1975 were wetter than normal if 1969-1975 were not wetter than normal, the source gauge for these data may be located further downstream Africa: Ghana Volta @ Senchi (Halcrow) WMO # GH AF 9074 RIV # River Gauge 50 Volta Senchi (Halcrow) • • • • UNESCO sources give 1934–1979 an independent source (IND) gives 1934–1984 these agree on concurrent months the joint UNESCO/IND set is retained • judging from coordinates, this gauge is likely identical to a site identified as Volta @ Akosombo Dam in modern references Black Volta @ Bamboi GH AF WMO # RIV # River Gauge 9960 1494 Black Volta Bamboi • • RIV and an independent source (IND) give Mar 1950–Feb 1974 these generally agree except for two typos in RIV • • • for Sep 1965, R1494 gives 102 IND gives 1020 the upstream gauge at Dapola, BF supports the IND discharge • • • for Sep 1969, R1494 gives 104 IND gives 1040 the upstream gauge at Dapola, BF supports the IND discharge • the corrected R1494 is retained under ID W9960 White Volta @ Yorugu (Yarigo) 67 GH AF WMO # RIV # River Gauge 9961 1495 White Volta Yorugu (Yarigo) • • RIV and an independent source (IND) give Mar 1966–Feb 1974 these generally agree except for a decimal shift typo in RIV • • • for Oct 1966, R1495 gives 534 IND gives 53.4 the upstream gauge at Yakala, BF supports the IND discharge Africa: Guinea Milo @ Kankan WMO # GN AF • • • 9040 RIV # 978 River Gauge Milo Kankan R978 has a long series (1945-1980) GRDC annual summary data span 1939–1980, but are missing some years present in R978 W9040 has only three years (1976-79) that have identical summary data to GRDC • • the underlying GRDC data are a different version of the series than R978 generally, GRDC and R978 plot nearly along a straight line, R978 annual averages are 1.5–2% higher than GRDC, and annual maxima are about 3% higher • in two years (1947 and 1979), R978 is unusually higher (4-5% on annual averages) than GRDC [or GRDC is unusually lower] the 1979 plot of R978 versus W9040 data [identical to GRDC in average and extrema] shows data still plot on a straight line, but that the slope is higher [5% versus ca. 1.7% for the other years] • • • • there is no doubt that R978 and GRDC/W9040 originate from the same source data, but differ by arbitrary scaling adjustments as both versions end in 1980, it is unclear which may be more recent or more correct R978 was accepted with a discharge of 18 for Apr 1965 added from GRDC after slight upward readjustment Niger @ Kouroussa 68 GN AF WMO # RIV # River Gauge 9963 1497 Niger Kouroussa • R1497 and GRDC annual summary data span 1945–1979 • • • • the underlying GRDC series is a different, slightly lower, version than R1497 the set of concurrent months plots nearly on a straight line the GRDC set of annual extrema have 6 months not in R1497 these were calibrated to R1497 equivalence (below) and added to R1497 1947 1950 1952 1953 1962 1979 GRDC RIV_est 206 94 188 156 349 4 210.3 96.6 192.1 159.6 355.5 4.6 7 7 7 12 11 5 Tinkisso @ Ouaran GN AF • • • • • • WMO # RIV # River Gauge 9964 1498 Tinkisso Ouaran R1498 and GRDC annual summary data span 1954–1978 the underlying GRDC series is a different version than R1498 the set of concurrent months plots nearly on a straight line GRDC is slightly lower on most months, but for some years the minimum and maximum are identical to R1498 the GRDC set of annual extrema have 2 months not in R1498 these were calibrated to R1498 equivalence and added to R1498 GRDC RIV_est 1964 5 1964 9 1978 10 • • • • 17 876 309 18.0 893.2 315.5 Nov 1978 R1498 discharge = 39 is likely wrong GRDC gives 309 Nov is typically 2nd wettest month of the year, and a sharp decline from Oct discharge of 270 and rise back 98 in Dec would be unprecedented because it appears that 309 may have been the intended R1498 entry, this was accepted over the calibrated estimate of 315.5 69 Africa: Ivory Coast (Cote d’Ivoire) Bandama @ Tiassale WMO # RIV # River Gauge Area CI AF 9174 1285 Bandama Tiassale 95,500 CI CI AF AF 9177 9170 1288 52 Bandama N'Zi Brimbo Zienoa 60,200 35,000 • • Tiassale is just below the junction of the Bandama and N’Zi Rivers the difference in drainage area between Tiassale and the two gauges just upstream of the confluence may be greater than the 300 km2 suggested by the reported drainage areas, but is likely < 1,000 km2 • • WMO and RIV have data only for 1979 and 1982–1983 an independent source (IND) has 1954–1991 • • • there are discrepancies between IND and WMO/RIV for Jan–Mar 1979 and Aug–Dec 1983, WMO/RIV are perceptibly lower than IND they are also lower than the sum of discharges for the two upstream gauges in Aug– Dec 1983 for Jan–Mar 1979, N’Zi has no data, but WMO/RIV are lower in Feb–Mar than the Bandama @ Brimbo alone on the other hand, IND discharges may be too high • • J F M A M J J A S O N D 9174 1979 IND 1979 28.6 29.0 15.0 46.8 22.0 40.6 45.3 45.5 61.3 61.4 281 282 308 309 485 485 763 763 654 650 228 229 162 161 9174 1983 IND 1983 74.0 75.4 92.0 92.6 91.0 92.0 113 113 113 113 133 133 96.5 97.9 8.4 19.3 5.1 15.2 3.4 13.4 42.5 49.0 22.0 30.2 • there is no obvious best choice and there are reasons to suspect both records for Bandama @ Tiassale during these periods • for the present, the joint IND/UNESCO set is retained with the WMO/RIV data for the concurrent periods Cavally (Cavalla) @ Tai WMO # RIV # River Gauge 9172 1283 Cavally (Cavalla) Tai CI AF • WMO and RIV have data only for 1979 and 1982–1983 70 • an independent source (IND) has 1954–1991 • • IND and WMO/RIV agree within rounding limits on concurrent data the joint IND/UNESCO set is retained Cavally (Cavalla) @ Tate WMO # RIV # River Gauge 9951 1485 Cavally (Cavalla) Tate CI AF • • R1485 has only 1979 GRDC summarizes 1979 and 1982, effectively giving all the data • • GRDC and R1485 disagree somewhat on 1979 the compensating errors have little effect on the annual mean; however, GRDC data give a closer fit to the 1979 data at the upstream gauge at Tai GRDC 1979 R1485 1979 J F M A 113 113 90 101 101 101 108 112 307 990 307 1020 -4 -30 dif • -11 M J J A S O N D mean 584 1004 1131 1468 584 1000 1170 1470 707 731 287 188 574 575 -24 99 4 -39 -2 GRDC data for 1979 and 1982 were retained Comoe @ Serebou CI AF • • • WMO # RIV # River Gauge Area 9176 1287 Comoe Serebou 48,700 WMO and RIV give only the three years below 5 months of 1983 disagree appreciably with the downstream gauge at Aniassue [see below] these were set to missing 1979 1982 1983 J F M A M J J A S O N D 2 32 1 3 0 0 0 7 14 17 11 101 10 8 179 19 34 297 64 49 828 137 71 538 61 32 83 28 36 23 61 Comoe @ Aniassue 71 WMO # CI AF RIV # 9169 53 River Gauge Area Comoe Aniassue 66,500 • • WMO and RIV give only 1979 and 1982–1983 an independent source (IND) gives the complete record for 1957–1991 • IND is retained Africa: Kenya Tana @ Garissa WMO # KE AF RIV # River Gauge 56 Tana Garissa 9043 • UNESCO sources and an independent source (IND) give 1934–1975 • there are some discrepancies that appear to be errata in WMO and RIV • • in file IHD, discharges from 1934–1964 remain in imperial units (ft3/s or cfs) after conversion, IHD agrees with IND except for 1940 when IHD data are subject to a parsing error in May 1940, the trailing digit “9” was pre-pended to Jun discharge, and likewise for successive months through Dec this is evident from comparing IND back-converted to imperial units the corrected IHD data are shown below [yellow shading] in cfs [“DA90 B” is the site ID code used in IHD] after correction, IHD agrees with IND, WMO, and RIV within rounding limits • • • • J F M DA90 B 1940 1816 1586 5789 DA90 B 1940 1816 1586 5789 A M J J A 9983 2049 9576 8408 8286 9983 20499 5768 4088 2866 S O N D mean 6198 3201 4570 7332 5733 1983 2014 5707 3320 5452 • there also appear to be 3 typos in WMO and RIV • • • for Nov 1941, W9043 and R56 give 21.5 m3/s IHD and IND give 216 m3/s a Nov discharge of 21.5 would be the lowest on record by more than 2-fold while 216 is typical the only two other occurrences of Nov discharges < 100 m3/s were during prolonged dry periods, but 1941 was not a drought year • 72 • the error is more likely in WMO and RIV • • for Jun 1942, W9043 and R56 give 319 m3/s (11,265 cfs) IHD and IND give 332 m3/s (11,729 cfs) • • for Aug 1956, W9043 and R56 give 71 m3/s (2490 cfs) IHD and IND give 99 m3/s (3495 cfs) • • • for May 1959, W9043 and R56 give 25.5 m3/s (900.5 cfs) IHD and IND give 257 m3/s (9075 cfs) this is the wettest month of the year; W9043/R56 makes no sense • • for May 1962, W9043 and R56 give 423 m3/s (14,938 cfs) IHD and IND give 523 m3/s (18,463 cfs) • the record retained is a composite of IHD data to 1964 after correction of 1941 and conversion to SI units, and 1964–1975 data from WMO/RIV Africa: Liberia Warning: Poor Quality Data • • • • discharge and metadata for Liberia are of poor quality as given, with the exception of the Saint Paul @ Walker Bridge gauge, the available gauges all have mean annual specific runoff (mm) exceeding mean annual rainfall rainfall averages ca. 2.5–3.5 m annually near the coast, and 1.7–2.6 m inland runoff is higher to the north near Sierra Leone, and lower to the south and east near Ivory Coast • outside the USA, Liberia is the last bastion of imperial measure; hence, some discharges may remain in ft3/s (cfs), or some drainage areas may be given in square miles not km2 • the St Paul @ Walker Bridge gauge seems to have about the right location coordinates and drainage area the specific runoff (692 mm) is consistent with the upstream gauge Diani @ DianiBac in Guinea • • an abstract by the French research agency ORSTOM gives the area for the Cestos @ Sawalo gauge as 4,600 km2 rather than the 683 km2 given by UNESCO sources 73 • • • the mean annual specific runoff for Sawalo using the ORSTOM estimate (363 mm) is similar to runoff in the nearest watersheds of Ivory Coast (400–630 mm) hence, it’s likely that the UNESCO drainage areas are in error discharge data for the St John @ Baila gauge are questionable as noted in a subsequent section WMO # River Gauge Area 2 km Discharge 3 km Runoff mm GN AF LR AF 9042 Diani 9093 Saint Paul Diani-Bac Walker Bridge 4,095 9,760 3.00 6.75 732 692 LR AF 9095 Cestos Sawolo 683 4,600 1.67 1.67 2,442 363 LR LR LR LR LR 9094 9098 9097 9099 9096 Unification Bridge Tournouta-Bafu Bay Baila Gbarnga Dougomai 761 575 39 246 1.30 3.77 4.50 0.19 1.52 4,952 7,818 4,851 6,182 AF AF AF AF AF Cestos Sehnkwehn Saint John Zor Ck Lofa CI AF CI AF CI AF 9171 Cavally (Cavalla) 9172 Cavally (Cavalla) 9951 Cavally (Cavalla) Flampleu Tai Tate 2,470 13,750 28,800 1.04 5.45 18.19 423 397 631 SL SL SL SL SL SL 9119 9124 9122 9123 9120 9125 Dodo Palima Jaï ama Sawafe Bumbuna Matotaka Moa Bridge 57 361 6,870 3,990 2,407 17,150 0.14 0.86 3.12 3.61 4.42 17.74 2,522 2,392 455 905 1,834 1,035 AF AF AF AF AF AF Maboa Bundoya Sewa Seli Pampana Moa Cestos @ Sawolo WMO # RIV # River Gauge LR AF 9095 1185 Cestos Sawolo CI AF 9171 1282 Cavally Flampleu • • 1983 in record R1185 is identical to 1983 in records R1282 / W9171 Cavally (Cavalla) @ Flampleu which seems to be the correct location the record is not in W9095 • 1983 was deleted for Cestos @ Sawalo 74 Cestos @ Unification Bridge WMO # LR AF LR AF • • • • 9094 9095 RIV # 1185 River Gauge Cestos Cestos Unification Bridge Sawolo W9094 had bad location coordinates, no drainage area, and no altitude nothing labelled “Unification Bridge” can be found in the usual geographic name data bases or maps as per figure below, site 9094 must be very close to site 9095 — so close that the 2 records could be spliced for operational purposes for mapping purposes, W9094 was assigned bogus coordinates placing it near W9095 200 175 150 125 100 75 50 25 0 1973 1974 1975 1976 Unification Bridge 1977 1978 1979 Sawolo Saint John @ Baila LR AF WMO # RIV # River Gauge 9097 1179 Saint John Baila • data for this gauge are not likely reliable and should be used with due caution • contrast against W9094/9095 Cestos @ Sawolo/“Unification Bridge” suggests that the W9097 / R1179 record for 1976–1979 is suspect or from another gauge ; discharges are generally higher, especially low flows, and 2 or more typos may be present 75 • Oct 1976 discharge of 46.5 in W9097 is a typo; R1179 gives 465 which is consistent with discharge patterns at sites W9095 and W9096 • the Oct 1977 discharge of 853 reported for in both W9097 and R1179 seems to be too high — comparison with other sites suggest it should be 300–500 m3/s, possibly higher, but not likely greater than 700 m3/s • in 1977, four other Liberian gauges all saw peak discharges during September, the missing month in both W9097 and R1179 — simple ratios suggest that discharge at site 9097 would have been in the 350–760 m3/s range, possibly higher as comparative data are meagre • because the evidence is weak, the Oct 1977 discharge was left as is 900 800 700 600 500 400 300 200 100 0 1973 1974 1975 1976 1977 9097 9094 1978 1979 9095 Africa: Madagascar Ikopa @ Antsatrana WMO # MG AF • • 9150 RIV # River Gauge 57 Ikopa Antsatrana WMO, RIV and an independent source (IND) have Oct 1948 – Oct 1982 with scattered missing months WMO and IND agree 76 • • • all versions report a spurious 0 for Sep 1980 the chance of this stream going to 0 is practically nil, particularly with discharges >100 m3/s in preceding and following months Sep 1980 was set to missing • RIV disagrees for the months below J F M A M J J A S O N D mean R57 W9150 1969 1969 789 789 972 972 560 560 554 554 292 292 199 199 170 170 149 149 117 117 120 120 181 133 744 900 404 413 R57 W9150 1970 1327 1970 1403 752 735 905 924 381 407 248 246 137 195 166 161 137 133 104 120 92 95 405 405 536 536 433 447 R57 W9150 1975 1975 1156 1111 1156 1111 555 555 310 320 239 239 197 199 164 115 120 120 142 142 471 471 530 530 483 480 • 796 796 WMO has been retained, but there is no obvious basis for choosing one or the other Mahavavy Nord @ Ambilobe MG AF • • • • WMO # RIV # River Gauge 9966 1501 Mahavavy Nord Ambilobe this is only available in RIV and an independent source (IND) RIV and IND are identical except for 1979 when RIV has 3 errors Apr and Jun 1979 discharges should be set to missing; the likelihood that discharge went to 0 at this site is nil Nov 1979 discharge was likely 84.5 as in IND not 34.5; the neighbouring stream [Sambirano @ Ambanja (not in UNESCO files) had similarly begun rising in Nov] 9966 1979 IND 1979 J F M A M J J A S O N D 267 267 665 665 834 834 0 - 168 168 0 - 79.4 79.4 58.2 58.2 34.8 34.8 32.1 32.1 34.5 84.5 218 218 Mananara @ Maroangaty WMO # MG AF • 9151 RIV # 58 River Gauge Mananara Maroangaty R58 has typos below: 1961 10 W9151 R58 seasonal 62.0 6 50.8 77 1966 8 1966 9 1966 10 • • 98.2 74.5 57.0 982 745 570 126.9 66.4 50.8 for Nov 1969 – Oct 1970, R58 disagrees somewhat with W9151 W9151 was accepted arbitrarily J F M A M J J A S 493 493 1525 1525 492 492 267 267 203 203 119 119 108 108 180 180 1185 1039 1136 1008 342 317 208 189 187 166 142 136 114 114 R58 W9151 1969 1969 R58 W9151 1970 1484 1970 1464 O N D mean 80.5 80.5 77.5 122.0 77.3 118.4 507 476 348 345 58.5 59.8 33.5 39.5 129 129 421 407 133 126 • • Nov–Dec 1976 in R58 were placed in 1977 where they are found in W9151 Madagascar data seem to be submitted on an operational year that runs from Nov through Oct of the following calendar year, so it’s unlikely that the two months would be orphaned in 1976 • as two complete Madagascar water years (Nov 1975 – Oct 1977) are missing in WMO and GRDC, the Nov-Dec 1975 data reported in R58 are potentially illegitimate these data are within the normal Nov–Dec range for this site and not replicates of other data pairs in the record, so they were left in the final composite data set • J F M WMO 1975 1976 1977 1978 853 140 525 138 RIV 1975 1976 1977 1978 853 140 525 138 A M J J A S O N D 414 293 192 149.0 119.0 102.0 101.0 175 55.9 47.2 61.3 28.2 62.6 39.4 58.9 43.1 108 - 299 - 414 293 192 149.0 119.0 102.0 101.0 175 55.9 47.2 61.3 28.2 63.0 39.4 59.0 43.1 82 108 - 215 299 - Mangoky Bevoay / Banian MG AF MG AF • • WMO # RIV # River Gauge 9044 9152 59 1504 Mangoky Mangoky Bevoay Banian Area 53,225 50,000 WMO gives the two distinct records R59 is a composite of Banian and Bevoay discharges, while R1504 gives the Banian discharges as in W9152 78 • • • • gauge W9044 Banian appeared to operate up to Oct 1965 gauge W9152 Bevoay began operation in Nov 1964 the sites are close enough to construct a single operational pseudo record, but the source data should be preserved separately for the correct gauge locations for the one overlapping year of record, the downstream site has a larger discharge • the two distinct records are retained as in W9044 and W9152 Africa: Mali Warning – Multiple Versions • • • the main gauges along the Niger [discussed separately in Niger Mid-Basin section] and several other Malian gauges have multiple record versions that differ mostly by apparently arbitrary adjustments of all or parts of the historical record discharge data appear to originate from the same source files, but have been fudged up or down according to the visions of the particular data series compiler about what historical discharges should be without a strong, well-documented rationale, it is difficult to accept that any one version is better than the others Bafing @ Dibia ML AF WMO # RIV # River Gauge 9972 1510 Bafing Dibia • • R1510 spans 1951–1978 GRDC summary data span 1951–1990 • from 1951–1962, R1510 generally matches GRDC summary data with the exception of one definite and one possible errors • • • • in Sep 1953, R1510 discharge = 145 GRDC reports 1450 Sep is generally the highest discharge month of the year the Aug and Oct discharges are 1009 and 739 respectively, making a Sep discharge of 145 implausible • • in Jan 1961, R1510 discharge = 68 GRDC reports 88 79 • either value is plausible, and changing the R1510 value would have little effect • • • from 1963–1978, relations between the two series vary from 1963–1969, GRDC peak discharges are significantly lower than R1510 peak discharges GRDC low discharges in 1966–1967 are significantly lower than reported by R1510 GRDC data for 1969 seem to be from another river as Jan-Apr (generally low season) discharges are listed as record highs 5-15 fold higher than reported by R1510 from 1970–1978, GRDC extrema are slightly higher than R1510 • R1510 is retained with the correction for 1953 listed above • • Baoule @ Dioila ML AF WMO # RIV # River Gauge 9970 1507 Baoule Dioila • • R1507 spans 1953–1979 with numerous missing months GRDC summary data span 1953–1990 with numerous missing months • • summary data for R1507 and GRDC are inconsistent over the common span there seem to be 4-5 distinct periods when the two versions are scaled somewhat differently • only the final common segment from 1968–1979 when GRDC summary data are consistently lower than R1507, has enough concurrent data to infer the scaling relationship between the two • on the first segment from 1953–1956, GRDC is perceptibly higher than R1507; and in 1956, the two may even represent different rivers or gauges the low season discharges, annual minima in the case of GRDC, are significantly higher than R1507 • • • before 1968, R1507 has 12 months not in GRDC from 1968–1979, GRDC has 14 months not in R1507 80 500 Mean annual discharge: Baoule @ Dioila 1953–1979 cms 400 300 200 100 GRDC • • 19 79 19 77 19 75 19 73 19 71 19 69 19 67 19 65 19 63 19 61 19 59 19 57 19 55 19 53 0 RIV for the present set, there is little choice but to accept R1507; however, these data should be used with caution 6 of 14 GRDC months not in R1507 are low season 0s that can be added to R1507 without scaling; even if these were not all 0s, they were all almost surely <1 m3/s Bakoy @ Oualia ML AF WMO # RIV # River Gauge 9971 1509 Bakoy (Bakoye) Oualia • • R1509 spans 1951–1978 with numerous missing months GRDC summary data span 1951–1990 with numerous missing months and whole years • R1509 and GRDC summary data are identical within rounding limits on concurrent months and annual averages except for two years which contain probable errors in R1509 • • • in Feb 1955, R1509 discharge = 141 changing this to 14.1 makes the annual average match the GRDC annual average the historical range for Feb discharges is 0–23, so 141 is almost surely wrong • • • • in Dec 1973, R1509 discharge = 130 changing this to 1.3 makes the annual average match the GRDC annual average the historical range for Dec discharges is 1–60 the Nov 1973 discharge = 8 and Jan 1974 discharge = 0.3 81 • hence, a Dec discharge of 1.3 is likely correct • R1509 was retained with the two corrections above Faleme @ Fadougou WMO # RIV # River Gauge Area ML AF 9973 1511 Faleme Fadougou 9,300 ML AF 9974 1512 Faleme Gourbassy 15,000 • • • RIV and an independent source (IND) give 1952–1978 at Fadougou RIV has 4 significant typos that are confirmed by data at Gourbassy otherwise IND and R1511 agree within rounding limits R1511 1956 1958 1972 1976 9 6 4 12 IND Gourbassi 61 208 140 190 610 20.8 1.4 19 1079 16.8 0 22 • R1511 is retained under ID W9973 with corrections from IND for the 4 typos listed above • • GRDC gives annual summary data for 1952–1990 on concurrent months, the annual peak discharges are often perceptibly higher or lower than those of R1512 Faleme @ Gourbassy ML AF WMO # RIV # River Gauge 9974 1512 Faleme Gourbassy • • R1512 and GRDC summary data generally agree on 1954–1978 GRDC is slightly lower • the following four discharges from GRDC were added to R1512 after slight upward calibration adjustment GRDC RIV_est 1954 1973 1974 1974 4 8 2 8 0 405 0 748 0.5 408.2 0.5 754.1 82 Sankarani @ Gaoula ML AF WMO # RIV # River Gauge 9969 1506 Sankarani Gaoula • • R1506 has 1954–1979 GRDC annual summary data span 1954–1990 • • the underlying GRDC version of the series is slightly lower the calibration plot of R1506 and GRDC falls nearly on a straight, but there is some perceptible scatter at the high end • this is an odd case where over the common 1954–1979 period, R1506 has 43 months not in GRDC, and GRDC has 5 other months not in R1506 • GRDC is ostensibly the more recent version, but that does not guarantee that the entire historical record has been revised • the following two months were added from GRDC after scaling adjustment GRDC RIV_est 1961 1 1968 2 50 67 52.9 70.3 • • • • Feb 1963 of R1506 is an error R1506 gives 808 the maximum for Feb according to GRDC summary data is only 98 Feb 1963 was set to missing • R1506 was retained with the changes above; however, the entire record should be retrieved from the source agency if the opportunity arises Senegal @ Galougo WMO # ML AF • • • 9047 RIV # 60 River Gauge Senegal Galougo WMO and RIV span 1905–1978 with some missing pieces GRDC summary data span 1905–1990 independent sources had monthly data for 1955–1959 (IND1) and daily discharges for 1987 and 1990 (IND2) 83 • WMO and RIV are mostly identical except on two distinct blocks a) May 1965 – May 1968 when WMO is marginally higher than RIV, and there is some curvature in the intercalibration relationship b) Apr 1970 – May 1975 when differences are smaller • IHD data for 1965–72 are identical to RIV, so that much of the RIV record is identical to what was submitted to UNESCO 25 years ago • most GRDC annual maxima are close to the annual maxima given by WMO/RIV, but occasional years are perceptibly different many annual low discharges given by GRDC are slightly higher • • • • • • • WMO and RIV have a probable typo for May 1955 discharge = 4 IND1 gives 47; but has slightly higher discharges than WMO/RIV for the period GRDC summary data list the minimum discharge for 1955 as 38 occurring in Apr WMO/RIV give 39 for Apr adjusted to statistical equivalence with WMO/RIV, the IND1 discharge for May 1955 is 43; this was substituted for the given discharge of 4 • • in the early part of the record, the same low discharges recur repeatedly this likely represents some general low discharge approximations rather than reliably metered/gauged discharge records there is not likely much that can be done about this but accept these pseudo data as is and view any conclusions regarding the behaviour of low discharges and long term trends accordingly • 1907 1908 1910 1915 1916 1917 1918 1920 1921 1922 1923 1924 • • J F M A M J J A S O N D 115 170 130 125 105 109 88 140 175 67 100 73 70 58 58 50 80 105 30 50 34 33 25 26 20 39 50 9 20 13 12 9 9 7 15 21 9 9 9 9 9 9 9 9 9 9 9 9 110 110 110 110 112 113 197 112 112 112 112 224 305 809 515 610 806 278 744 380 305 493 510 1456 916 2152 1950 1910 1907 1870 2795 2000 1309 2699 1721 3202 1807 2736 2542 1769 2505 2541 3168 3055 1941 3747 2826 3677 1031 1094 999 959 1266 889 1722 1034 730 1189 1044 1739 440 383 370 193 392 376 407 315 240 637 640 664 205 260 170 215 200 180 310 190 160 307 310 308 WMO has been retained; but there is no obvious reason for choosing one set over the other and little impact on the basic summary stats either way monthly means for 1987 and 1990 from IND2 were appended 84 Senegal @ Kayes ML AF • • • WMO # RIV # River Gauge 9881 1191 Senegal Kayes RIV has data for 1952–1988 a set of independently obtained monthly discharges (IND) spanned 1952–1990 with 1989 missing RIV and IND are identical on common months except for minor rounding discrepancies (IND appears to have been derived from daily discharges without rounding) and four typos listed below: 1953 3 1960 6 1973 12 1981 12 • • • RIV IND seasonal 306.0 734.0 98.2 95.9 30.6 73.4 68.2 65.9 24.4 49.7 150.2 150.2 RIV data for Mar 1953 and Jun 1960 are almost surely in error for the small discrepancies Dec 1973 and Dec 1981, RIV values are closer to the seasonal norm, but the IND data are well within the typical Dec range of variability IND was retained Africa: Mauritius Deep @ Pont Lardier MU IO • WMO # RIV # River Gauge 9103 1193 Deep Pont Lardier Aug 1981 R1193 should be 2.16 not 1.2 Africa: Niger Komadougou Yobe @ Bagara Diffa WMO # RIV # River Gauge 85 Area UNESCO Fekete et al. NE AF • • • 9054 1514 f Komadougou Yobe Bagara Diffa 115,000 449,161 note that drainage area estimate of Fekete et al. (1999) suggests that the UNESCO drainage area likely underestimates the true extent of desert drainage however, Fekete et al.’s estimate may be too high; so the UNESCO drainage area is retained for the time being Apr 1972 R1514 should likely be 0.04 not 4.00 Africa: Rwanda Kagera and Nyabarongo Rivers RW AF RW AF RW AF • • • • WMO # RIV # River Gauge 9178 9179 9180 1306 1308 1307 Kagera Nyabarongo Nyabarongo Rusumo Kigali Kanzenze UNESCO (WMO and RIV) have 1965–1984 at these sites an independent source (IND) also has 1958–1984 for the Kagera @ Rusumo, and Jul 1956 – Jun 1961 plus 1965–1984 for the two Nyabarongo sites IND and UNESCO agree on concurrent months the joint IND/UNESCO data sets are retained Africa: Senegal WARNING — RIV Time-Shift: Jan–Apr 1976–1979 • • • • • • for 12 of 13 Senegalese records (yellow shading); the Jan–Apr data given by RIV for 1976–1979 are back-shifted one year, i.e., Jan-Apr of year i are the data for year i+1 as given by WMO and, for several sites, an independent source Senegal appears to submit monthly data on a May–Apr operational year the problem with RIV may have resulted from misinterpretation of the shift required to bring data from local water years onto calendar year basis where RIV records begin before 1976, the correct Jan–Apr 1976 data are lost where RIV records extend after 1979, the 1980 Jan–Apr data appear twice, in 1979 and 1980 at some smaller watersheds, the effect is only evident in Jan–Feb data as Mar-Apr data are all 0s SN AF WMO # RIV # River Gauge Area 9066 1020 Casamance Kolda 3,700 86 SN SN SN SN SN SN SN SN SN AF AF AF AF AF AF AF AF AF 9060 9059 9056 9057 9062 9067 9061 9064 9063 1013 1015 1012 1017 1220 1011 1019 1014 1221 Diarha Faleme Gambie Gambie Gambie Gambie Niaoule Niokolo-Koba Thiokoye Pont Routier Kidira Mako Simenti Gouloumbou Kedougou Niaoule Tanou Pont Routier Pont Routier 760 28,900 10,450 20,500 42,000 7,550 1,230 3,000 950 SN AF SN AF 9058 9065 1218 1018 Gambie Gambie Wassadou amont Wassadou aval 21,200 33,500 SN AF 9055 70 Senegal Bakel • 218,000 the shift is shown below for Diarha @ Pont Routier W9060 R1013 yr J F 1973 1974 1975 1976 1977 1978 1979 1980 0.040 0.020 0.440 0.331 0.210 0.007 0.238 0.239 0.000 0.000 0.040 0.034 0.033 0.000 0.006 0.047 yr J F 1973 0.040 0.000 1974 0.020 0.000 1975 0.440 0.040 1976 1977 1978 1979 1980 0.210 0.010 0.240 0.240 0.240 0.030 0.000 0.010 0.050 0.050 • the same effect is most likely present in two Gambia River sites (green shading) but for these two, RIV have reversed the metadata, i.e., data for R1218, nominally “Wassadou amont” (upstream) are actually for “Wassadou aval” (downstream), and vice versa • • one record, Senegal @ Bakel, is unaffected by the Jan–Apr time-shift this is a long record that may have been received as a single contiguous block • • to construct records for the present set, WMO was used as the base for some sites, additional data available only in RIV were added for pre-1976 and post-1979 periods only • some other problems were found with these records as discussed below Faleme @ Kidira SN AF • WMO # RIV # River Gauge 9059 Faleme Kidira 1015 all sources give identical data for this gauge that spans 1930–1983 87 • • • • the pre-1950 data are not likely too reliable as seen below, there is an excessively high recurrence frequency of certain discharges and discharge sequences some of this is likely due to low digital precision, but some numbers recur in particular sequences at implausible frequencies the 1930–1947 data are retained but should be used with due caution 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 J F M A M J J A S O N D 18 22 14 14 13 27 23 17 29 14 18 8 6 11 13 8 10 7 7 7 14 12 9 15 7 9 5 4 6 7 4 5 3 3 3 6 6 4 7 3 4 2 2 2 3 1 2 1 1 1 2 2 1 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 - 10 24 11 112 24 24 38 24 24 24 24 24 24 24 24 - 88 269 253 404 82 255 101 114 103 86 90 116 50 50 100 - 870 462 616 1259 939 1423 1078 453 417 637 341 328 528 153 738 - 975 831 570 722 917 1491 1480 950 1107 526 218 583 332 338 831 - 458 468 320 202 229 636 542 261 482 325 401 169 64 136 402 - 67 85 59 55 66 127 196 136 375 59 147 39 25 57 59 - 34 43 28 26 29 55 52 37 69 28 38 19 13 23 27 - Gambie @ Kedougou / Gouloumbou WMO # RIV # River Gauge 9067 9056 9057 9062 Gambie Gambie Gambie Gambie Kedougou Mako Simenti Gouloumbou Lon El Area 12.55 12.86 13.03 13.47 -12.17 -12.35 -13.30 -13.73 102 75 10 - 7,550 10,450 20,500 42,000 SN SN SN SN AF AF AF AF • 1984 flood season data (May–Dec) are identical for W9067 and W9062, the most upstream and downstream sites R1011 has May–Dec 1984 identical to W9067 Kedougou R1220 has no 1984 data • • • • 1011 1012 1017 1220 Lat examination of the seasonal discharge patterns at all four sites shows that the May– Dec 1984 data at W9067 / R1011 are almost surely wrong generally, the seasonal peak flow have the expected order Kedougou ≤ Mako < Simenti < Gouloumbou 9067 1984 1 5.62 9056 9057 9062 10.30 88 1984 1984 1984 1984 1984 1984 1984 1984 1984 1984 1984 • • • 2 3 4 5 6 7 8 9 10 11 12 2.23 0.44 0.01 18.70 41.10 185.00 193.00 226.00 328.00 60.10 24.70 0.45 17.70 111.00 93.80 99.30 112.00 23.00 9.33 0.13 42.00 171.00 164.00 160.00 193.00 30.90 7.47 9.03 10.50 15.40 18.70 41.10 185.00 193.00 226.00 328.00 60.10 24.70 the figure below shows the consistency of the seasonal peaks at Kedougou and Mako — consistency that is only violated in 1984 for the given May-Dec 1984 Kedougou discharges to be correct, all three downstream gauges would have to have erroneous discharge data thus May-Dec 1984 were deleted for both W9067 and R1011 800 700 600 500 400 300 200 100 0 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 9067 • • • • 9056 the figure and the data below also show what is most probably a typo in the Jul 1978 datum at Kedougou the peak season discharge at Kedougou never leads the downstream sites, particularly Mako, by such high discharge, or conversely, if discharge were that high at Kedougou, discharges at the downstream sites would be have to be greater the correct discharge is likely 44.7 m3/s, which is very close to what’s expected given the downstream data both W9067 and R1011 have the same error 1978 6 9067 9056 9057 9062 7.7 9.3 9.9 14.6 89 1978 1978 1978 • 7 8 9 447 313 418 48.6 359 504 116 559 744 139 619 875 Jul 1978 discharge at Kedougou was changed to 44.7 m3/s Gambie @ Wassadou amont / aval WMO # RIV # River Gauge Area El Lat Lon SN AF SN AF 9058 9065 1218 1018 Gambie Gambie Wassadou amont Wassadou aval 21,200 33,500 5 13.35 -13.37 4 13.35 -13.38 SN AF 9057 1017 Gambie Simenti 20,500 10 13.03 -13.30 • • amont (properly en amont) = upstream aval (properly en aval) = downstream • the two gauges “Wassadou amont” and “Wassadou aval” are located in close proximity upstream and downstream of Wassadou town respectively • • the drainage area given for “Wassadou amont” is wrong the given estimate of 21,200 km2 would imply that the gauge were in close proximity to the upstream gauge at Simenti which is not supported by the given location coordinates or the available discharge data the true drainage area of “Wassadou amont” is likely in the range 30,000–33,500 km2 for the present, a drainage area of 31,200 has been assumed for “Wassadou amont” this is likely wrong, but close enough to give reasonable estimates of specific runoff • • • • RIV has reversed the discharge and metadata, i.e., data for R1218, nominally “Wassadou amont” (upstream) are actually for “Wassadou aval” (downstream), and vice versa • after the R1218 and R1018 data are assigned to the correct gauges, RIV data still have the Jan–Apr 1976–1979 time-shift error • after the above corrections, concurrent discharges for the upstream gauge are consistently lower on annualized basis than at the downstream gauge • • one potential problem remains there are data for May 1981 – Apr 1983 that were only available in the original R1018 record if these data were consistent with other data given originally in R1018, they should represent the upstream gauge • 90 • • • given that RIV had already scrambled data at these sites in two different ways, it remains possible that the 1981–1983 data may have also been incorrectly assigned but there is no way of confirming this as WMO has no 1981–1983 data for the upstream gauge for the present, it is assumed that these 1981–1983 data represent the upstream gauge, but this may be wrong Senegal @ Bakel WMO # SN AF RIV # 9055 70 River Gauge Senegal Bakel Area UNESCO Fekete et al. 218,000 591,218 • the drainage area given by UNESCO may significantly underestimate the actual drainage area as suggested by the estimate given by Fekete et al. (1999) • • • UNESCO has data from 1904–1984 between WMO and RIV there are only some minor discrepancies a small set of independent daily discharges has data for May 1979 – Apr 1985 which have monthly data identical to UNESCO on concurrent months WMO is retained with Jan–Apr 1985 from the independent set appended • Niokolo-Koba @ Pont Routier SN AF WMO # RIV # River Gauge 9064 1014 Niokolo-Koba Pont Routier • WMO and RIV have 1970–1980 • • Jun–Sep 1977 of R1014 are likely in error the nearest small drainage area gauges (Diarha and Thiokoye) have from 0–5 m3/s discharge for Jun–Aug, and significant discharge in Sep, i.e., the 0s reported by R1014 for Jun–Aug are likely wrong W9064 1977 R1014 1977 J F M A M J J A S O N D 0 0 0 0 0 0 0 0 0 0 0 0 0 20 2 - - - Africa: Somalia 91 Shebelle @ Belet Uen SO AF WMO # RIV # River Gauge 9987 1546 Shebelle Belet Uen • • R1546 and GRDC summary data span 1951–1979 these agree except for 1 month • • • for Dec 1975, R1546 discharge = 0 GRDC gives 8 as the preceding month had 34 m3/s, GRDC is more likely correct Shebelle @ Buulo Barde (Bulo Berti) WMO # RIV # SO AF SO AF 9988 9987 1547 1546 River Gauge Area Shebelle Shebelle Buulo Barde (Bulo Berti) Belet Uen 231,000 211,800 • • R1546 and GRDC summary data span 1951–1978 these agree except for 1978 • • • in 1978, data for Jul–Dec in both R1547 and GRDC are almost surely wrong these bear no relation to discharges not far upstream at Belet Uen discharges generally decline as the Shebelle moves downstream through the desert; on limited comparative data, for most concurrent months discharges at Belet Uen are higher than at Buulo Barde Jul-Dec discharges were set to missing values • J F M A M J J A S O N D GRDC 1978 R1547 1978 62 62 - - - - - 134 134 210 210 26 0 299 0 1 0 1 R1546 1978 27 11 83 49 87 31 65 138 194 159 110 28 Africa: South Africa Limpopo @ Oxenham Ranch ZA AF • • • WMO # RIV # River Gauge 9201 1515 Limpopo Oxenham Ranch WMO and RIV give 1964 – 1980 with numerous missing months the two are identical within rounding jitter except for a typo in RIV W9210 has higher digital precision on low discharges 92 • • • for Oct 19684, R15165 discharge = 221 is an error W9201 gives 2.21 W9201 is supported by the downstream gauges at Beitbrug / Beitbridge • W9201 is retained Orange @ Upington ZA AF ZA AF ZA AF • • • • • WMO # RIV # River Gauge 9205 9206 9207 Orange Orange Orange Aliwal Noord Upington Vioolsdrift 1453 1458 1459 Area UNESCO Fekete et al. 37,075 36,456 850,530 29,400 352,345 838,168 Lat Lon -30.69 26.71 -28.46 21.24 -28.78 17.63 in every available UNESCO source, including the GRDC catalogue, the drainage area of the Upington gauge is given incorrectly the uppermost gauge of these three, Aliwal Noord, is near the Lesotho border Upington is far downstream near the Namibia border the Upington drainage area is ca. 10-fold higher, than Aliwal Noord Fekete et al.’s (1999) Upington drainage area of 352,345 km2 has been adapted for the present metadata; this may be low, but will give better estimates of specific runoff Vaal @ de Hoop 65 ZA AF • WMO # RIV # River Gauge 9204 1517 Vaal de Hoop 65 Aug 1986 R1517 discharge should be 1.3 not 13 Africa: South Africa / Zimbabwe Limpopo @ Beitbrug / Beitbridge Pumpstation c/s ZA AF ZW AF • WMO # RIV # River Gauge Area 9202 9883 1516 1542 Limpopo Limpopo Beitbrug Beitbridge Pumpstation c/s these two gauges are practically opposite each other 93 201,000 196,000 Lat Lon -22.22 29.99 -22.22 29.98 • the actual difference in drainage areas is likely less than the 5,000 km2 suggested by the given drainage areas • the South African gauge has data for Oct 1964 – Dec 1980 with scattered missing pieces WMO and RIV are identical for rounding jitter and some typos in RIV • • • the Zimbabwean gauge has data for Oct 1959 – Dec 1980 with scattered missing pieces these data are given by RIV and an independent source (IND) which are identical except for rounding jitter Errata: R1516 • RIV record R1516 has several errata • • • • for Jan 1968, R1516 Limpopo @ Beitbrug discharge = 299 W9202 gives 2.99 R1542 Limpopo @ Beitbridge Pumpstation c/s gives 25.3 W9202 is retained but there is obviously a discrepancy between the two gauges • • • • for May 1972, R1516 Limpopo @ Beitbrug discharge = 111 W9202 gives 11.1 R1542 Limpopo @ Beitbridge Pumpstation c/s gives 0.14 W9202 is retained but again there is obviously a discrepancy between the two gauges • • • • for Aug 1979, R1516 Limpopo @ Beitbrug discharge = 0.13 W9202 gives 0.013 R1542 Limpopo @ Beitbridge Pumpstation c/s gives 0.00 W9202 was retained Discrepancies Between Gauges • • despite the proximity, there are ubiquitous, significant discrepancies between these two gauge record on concurrent months the net effect is that for 167 common months, the mean annual discharge reported by the South African gauge is perceptibly lower than that of the Zimbabwean gauge W9202 J F M A M J J A S O N D mean 113 324 157 92 32 13 7 4 2 4 16 65 69 94 R1542 • • • • 176 369 177 95 34 16 10 6 4 5 18 77 82 the quality of data produced at one or both gauges is not especially high a list of the more significant discrepancies is shown below these discrepancies span the entire record there is no resolution for these discrepancies short of examining source records and improving the quality of the stream gauging effort 1964 1965 1966 1967 1967 1967 1967 1968 1969 1969 1969 1970 1970 1970 1971 1971 1971 1971 1972 1972 1973 1974 1974 1975 1975 1975 1975 1975 1976 1976 1976 1976 1977 1977 1977 1978 1978 1978 1978 1978 1978 1979 12 1 3 2 6 7 8 12 1 3 4 1 3 12 1 3 4 12 1 5 2 2 5 2 3 4 7 8 3 7 8 9 1 2 3 2 7 8 9 10 12 2 R1542 W9202 dif %dif 148.00 82.90 56.00 1178.00 42.10 21.90 14.10 56.00 25.30 278.00 55.20 37.70 9.63 41.40 482.00 24.10 7.72 72.10 885.00 0.15 21.50 260.00 31.80 975.00 392.00 320.00 26.40 15.00 280.00 41.10 26.40 12.80 14.10 485.00 459.00 1095.00 30.60 19.70 11.50 19.80 15.00 11.00 105.00 1.59 10.80 1483.00 25.80 15.30 7.23 18.20 2.99 104.00 21.70 10.60 1.93 25.90 384.00 50.90 47.00 55.50 366.00 11.00 16.10 323.00 23.70 561.00 297.00 244.00 19.20 10.80 330.00 31.90 19.60 7.48 9.09 361.00 415.00 721.00 21.20 11.40 6.29 9.24 9.86 4.51 43.00 81.31 45.20 -305.00 16.30 6.60 6.87 37.80 22.31 174.00 33.50 27.10 7.70 15.50 98.00 -26.80 -39.28 16.60 519.00 -10.85 5.40 -63.00 8.10 414.00 95.00 76.00 7.20 4.20 -50.00 9.20 6.80 5.32 5.01 124.00 44.00 374.00 9.40 8.30 5.21 10.56 5.14 6.49 34 192 135 -23 48 35 64 102 158 91 87 112 133 46 23 -71 -144 26 83 -195 29 -22 29 54 28 27 32 33 -16 25 30 52 43 29 10 41 36 53 59 73 41 84 95 • • • • N.B. there is a large decimal shift discrepancy in the GRDC version of Limpopo @ Beitbridge Pumpstation that has been copied into other versions of this series for Mar 1975 GRDC discharge = 3920 R1542 gives 392 and W9202 gives 297 R1542 seems to be correct Africa: Sudan Nile Basin Drainage Area Estimates WMO # RIV # River Gauge SD AF SD AF SD AF 9976 9156 White Nile (el Jabel) Mongalla White Nile (el Jabel) Malakal White Nile (el Jabel) Mogren (Khartoum) ET AF SD AF 9154 9154 Blue Nile Blue Nile Sudan border Khartoum SD AF 9975 Atbara Kilo 3 SD AF 9155 Nile Dongola (Dunqulah) a b 76 Area UNESCO Fekete et al. a FAO 450,000 1,080,000 b 1,588,194 555,881 1,185,196 1,849,988 1,084,140 1,687,880 325,000 275,123 162,054 311,870 69,000 178,709 173,580 221,738 2,694,000 2,694,484 from supporting data files for FAO (2001) from GRDC • again, inconsistent drainage areas have been reported by various sources • • the most egregious discrepancy is the UNESCO area for the Atbara @ Kilo 3 which almost surely is in mi2 rather than km2 69,000 mi2 = 178,709 km2 which is very close to Fekete’s estimate • for the present, the medians of available estimates have been accepted Atbara @ Kilo 3 SD AF WMO # RIV # River Gauge 9975 1522 Atbara Kilo 3 • RIV and an independent source (IND) give 1912–1982 • RIV has the following data entry errors • Dec 1922 R1522 discharge = 635 is an error 96 • • IND gives 6.35 this is a low discharge month; 635 is implausible, it would be the highest Dec discharge on record by 10-fold • in 1957, the Mar discharge of 11 was entered into Apr pushing the rest of the year forward 1 month and losing Dec IND has the correct sequence • 9975 1957 IND 1957 • J F M A M J J A S O N D 42 42 25 25 11 11 11 6 6 3 3 28 28 288 288 1967 1967 1211 1211 153 153 42 42 27 the corrected version of R1522 was retained (under ID W9975) Blue Nile @ Khartoum SD AF WMO # RIV # River Gauge 9154 1225 Blue Nile Khartoum • • • WMO and RIV have 1912–1982 an old independent set (IND) has 1900–1927 GRDC annual summary data span 1900–1982 • over 1912–1982 these mostly agree except for some discrepancies with R1225 • IND is slightly higher (0.1–2%) than the others on concurrent months (1912–1927), and there are a few discrepancies that are large in percentage terms but have little effect on the annual averages or general character of the time series, e.g., in Jun 1912 IND gives 329 and WMO has 186 contrast of mean annual discharges against Nile @ Aswan suggests that the 1900–1911 data are generally good • 97 mean annual discharge cms 4500 4000 3500 3000 2500 2000 1500 1000 18 71 18 75 18 7 18 9 83 18 87 18 91 18 95 18 99 19 03 19 07 19 11 19 1 19 5 19 19 23 19 27 19 31 19 35 19 39 19 43 19 47 19 51 19 5 19 5 59 19 63 19 67 19 71 19 75 19 79 19 83 500 Nile - Aswan • • • Blue Nile - Khartoum GRDC summary data before 1912 comprise only 1900 which is given completely because all months are record lows this looks similar to the IND 1900 scaled down by 10, crudely rounded, and with minor typos or conversion errors three discrepancies between RIV and the others are listed below R1225 W9154 1915 5 1936 10 1970 3 • 1339 3830 191 1239 2830 181 the series retained is a composite of IND from 1900–1911 and W9154 from 1912– 1982 White Nile (el Jabel) @ Mongalla SD AF • • WMO # RIV # River Gauge 9976 1523 White Nile (el Jabel) Mongalla RIV and GRDC series span 1912–1982 these agree except for 3 months 1930 7 1964 6 1979 6 GRDC RIV dif 679 1905 1766 979 1505 1966 -300 400 -200 98 • • there are no records near enough to indicate which entries are correct the GRDC version is accepted arbitrarily Africa: Sudan / Ethiopia Blue Nile @ Sudan border ET AF SD AF SD AF WMO # RIV # River Gauge Area 9032 12 9154 1225 Blue Nile (Abbay) Blue Nile (Abbay) Blue Nile (Abbay) Sudan border Roseires Dam Khartoum 162,054 210,000 311,870 • • Abbay is the Ethiopian name for the Blue Nile Blue Nile @ Sudan border is nominally an Ethiopian gauge at roughly the upstream end of the impoundment behind Sudan’s Roseires Dam • • • U72 / RIV / WMO have the same data for 1969–1972 RIV / WMO also data for 1973–1975 GRDC gives summary data for Blue Nile @ Roseires Dam (GRDC # 1663800) • as per the figure below, the 1973–1975 discharges reported by RIV / WMO 3-fold too high, and even higher than the combined White Nile / Blue Nile discharges below the confluence at Khartoum 7000 6000 Blue Nile mean annual discharges 1969-1973 cms 5000 4000 3000 2000 1000 0 1968 1969 1970 border A • 1971 1972 border B 1973 Roseires Dam U72 / RIV / WMO 1969–1972 data are retained 99 1974 Khartoum 1975 1976 • the 1973–1975 data from RIV / WMO are listed below on the chance that someone may know where they belong 1973 1974 1975 J F M A 548 762 - 302 438 - 214 394 420 174 285 276 M J J A S O N D 679 1604 5204 16118 11461 6029 2306 1165 775 2034 8512 16138 11934 5850 2310 1288 405 3786 15699 16880 7242 - Africa: Tanzania Great Ruaha @ Mtera TZ AF WMO # RIV # River Gauge 9980 1527 Great Ruaha Mtera • • • R1527 spans 1955–1979 with many missing months GRDC spans the same period with slightly lower discharges GRDC has 8 months not in R1527 • the 8 months from GRDC not in R1527 were scaled up to statistical equivalence with R1527 by calibration as below and added to R1527 Feb-Mar and May 1968 were exceptionally high, but several area rain gauges reported record high rainfall for the 12 months from May 1967 – Jun 1968 some may wish to delete these estimates or substitute GRDC values for some purposes • • 1973 1974 1978 1956 1974 1968 1968 1968 GRDC R1527_est 5 94 329 335 427 545 631 926 5.63 96.9 336 342 438 560 649 954 10 7 1 2 5 5 2 3 Kilombero @ Swero WMO # TZ AF • 9915 RIV # 71 River Gauge Kilombero Swero R71 has only 191 months between Dec 1957 and Dec 1981 100 • • • • GRDC summary data span the same period the underlying GRDC series has 211 months GRDC data are lower than R71 data by 2-3% differences become perceptible at >400 m3/s, but remain small in percentage terms • the 20 months from GRDC not in R71 were scaled up to statistical equivalence with R71 by calibration as below and added to R71 some may wish to delete these estimates or substitute GRDC values for some purposes • GRDC R71_est 1981 1978 1980 1979 1980 1972 1965 1969 1973 1977 1975 1978 1972 1979 1967 1967 1973 1971 1968 1974 9 11 11 11 2 10 11 12 11 5 11 4 7 4 12 5 5 5 4 5 33 34 35 42 45 110 116 123 150 174 197 204 265 422 590 1091 1437 1461 2170 2463 33 34 36 43 46 113 119 126 152 176 200 207 270 431 604 1119 1474 1499 2227 2528 Rufiji @ Stiegeler's Gorge TZ AF WMO # RIV # River Gauge Area 9979 1526 Rufiji Stiegeler's Gorge 158,200 • • R1526 has Nov 1954 – Dec 1958 with numerous missing months GRDC summary data have the same period with some months not in R1526 • the underlying GRDC series is mostly lower than R1526 by a few % • • • R1526 has 4 spurious 0s this is a strong perennial stream; the likelihood of 0 discharge is practically nil the 0s were set to missing values J F M A M J 101 J A S O N D R1526 1974 286 345 503 1512 - 0 - 153 0 0 215 337 R1526 1978 782 955 2176 2207 1067 414 270 0 179 158 208 601 • • • the three discharges from GRDC summary data not in R1526 were scaled to equivalence with R1526 and added to R1526 May 1975 is exceptionally high, but this also occurred on the Kilombero tributary some may wish to delete these estimates or substitute GRDC values for some purposes 1967 1 1974 5 1974 7 GRDC R1526_est 741 5098 222 753 5210 227 Ruvu @ Dar-Es-Salam—Morogoro Rd Bridge TZ AF WMO # RIV # River Gauge 9981 1528 Ruvu Dar-Es-Salam— Morogoro Rd Bridge • • R1528 gives Nov 1959 – Dec 1978 with scattered missing months GRDC summary data span the same period with slightly lower discharges and two months not in R1528 • the two months in GRDC not in R1528 were scaled up by calibration and added to R1528 1971 4 1972 2 GRDC R1528_est 133 10 136 10.6 Africa: Togo Mono @ Dotekope (Kolokope, Correkope ?) WMO # TG AF • • • 9068 RIV # River Gauge Area 18 Mono Kolokope (Correkope ?) 9,900 metadata for this gauge are muddled WMO, RIV, and GRDC gave the name as Correkope virtually no place names in Togo begin with “C” let along “Cor” 102 • “Kolokope” is the most similar name to Correkope that can be found on the river near to the assigned coordinates • the UNESCO/ORSTOM sponsored Observatoire Hydrologique Régional de l'Afrique de l'Ouest et Centrale [OHRAOC] which should be a better source, lists a gauge “Mono @ Dotekope” which may be the correct location Dotekope is on the river a few km north of Kolokope • • • • • the drainage for the site was given incorrectly by WMO, GRDC and OHRAOC WMO and GRDC give 995 km2 which is 10-fold too small OHRAOC gives 5,590 km2 which is also too small the drainage area is ca. 10,000 km2, so the RIV estimate of 9,900 km2 or the scaledup WMO/GRDC estimate of 9,950 km2 are about right Oti @ Mango (Sansanne-Mango) TG AF WMO # RIV # River Gauge 9982 1529 Oti Mango (Sansanne-Mango) • • • R1529 gives 1953–1973 an independent source (IND) gives 1953 – Feb 1974 GRDC summary data span the same period as IND • generally, these all have the same data on concurrent months • • • R1529 has a typo in 1970 for Aug 1970, R1529 discharge = 256 IND gives 296 which makes the annual average identical to GRDC • R1529 was retained with the correction above and the addition of Jan–Feb 1974 from IND Africa: Tunisia Medjerda @ Ghardimaou TN AF • • WMO # RIV # River Gauge 9127 1531 Medjerda Ghardimaou the UNESCO sources have only 1976–1979 an independent source (IND) has a monthly mean series for 1949–1995 103 • MED-HYCOS has daily discharges for 1949–1998 and an alternate monthly series • monthly means of the two MED-HYCOS series differ slightly, likely because there are scattered months patched with estimates when daily data were incomplete or missing • UNESCO files agree mostly with IND and MED-HYCOS data except for rounding jitter and a typo in Dec 1979 that is common to WMO and RIV (74 should be 0.74) • spot checks on scattered years show that IND seems to be a hybrid mostly similar to the monthly means derived from daily discharges, but occasionally similar to the MED-HYCOS monthly series the checks also suggest that the daily and monthly series at MED-HYCOS may each contain a few data entry errors • • IND has been retained Africa: Uganda Nile Basin Drainage Area Estimates WMO # RIV # UG UG UG UG AF AF AF AF 9158 9157 SD AF 9155 a b • • • • 76 River Gauge Victoria Nile Victoria Nile Victoria Nile Victoria Nile Owen Reservoir Mbulamuti Paraa to Lake Albert Nile Dongola (Dunqulah) Area UNESCO Fekete et al. b 269,000 253,133 340,000 342,767 a FAO 257,794 337,637 2,694,000 2,694,484 from supporting data files for FAO (2001) from GRDC the UNESCO drainage area for Owen Reservoir at the outlet Lake Victoria is high relative to other estimates the median of the three alternatives [FAO] is accepted if the FAO estimate of drainage area up to Victoria Nile’s outlet to Lake Albert is correct, the drainage area at Paraa may be only 330,000 km2 for the present, the UNESCO area is retained Manafwa @ Bulucheke/Butaleja — WARNING: dubious record 104 WMO # UG AF 9071 RIV # 788 River Gauge Manafwa Bulucheke/Butaleja Lat Lon Area 1.00 34.35 65 • • either the drainage area or the discharge data are wrong mean annual specific runoff for the available 4 years of discharges is almost 3 m; that is 2-fold higher than annual rainfall, and 10-fold higher than specific runoff other Ugandan streams • location coordinates are also dubious Muzizi @ Hoima-Fort Portal Rd WMO # UG AF 9070 RIV # 784 River Gauge Muzizi Hoima-Fort Portal Rd • • • • UNESCO sources had 1976–1979 an independent source (IND) has 1956–1968 and 1976–1979 IND and UNESCO agree on concurrent months the joint IND/UNESCO set is retained • • N.B. 1961–1964 have unusually high runoff with atypical seasonal patterns several rain gauges from the periphery of the of the Muzizi watershed also report unusual rainfall for these years Africa: Zambia Kabompo ? @ Manyinga Rd Bridge ZM AF • • • • WMO # RIV # River Gauge 9136 1457 Kabompo ? Manyinga Rd Bridge this site has been identified as both the Kabompo [WMO] and Manyinga [RIV] Rivers the Manyinga is an affluent of the Kabompo that enters at the town of Manyinga just to the northeast of Manyinga town, there is a bridge spanning the Kabompo for the present, the data are assumed to be for the Kabompo River; this might be wrong 105 Africa: Zimbabwe Gwaai @ Kamativi g/w ZW AF WMO # RIV # River Gauge 9930 1316 Gwaai Kamativi g/w • • • UNESCO data were limited to R1316 for 1955–1984 with missing months an independent source (IND) and GRDC summary data span the same period generally these agree except for 1983 • R1316 seems to have entered data for 1984 in 1983 as well as 1984 J F M 9930 1983 IND 1983 2.5 10.5 3.5 19.0 2.0 9930 1984 IND 1984 2.5 2.5 3.5 3.5 • • A – – 0.2 – – M J – 0.0 – – J – 0.0 – – A – 0.0 – – – 0.0 – – S – 0.0 – – O N – 0.0 – – D – – – – – – – 0.0 – – IND data were accepted for 1983 and 1984 R1316 is retained with the corrections for 1983 and 1984 noted above Hunyani (Manyame ?) @ Mangula Mine Weir ZW AF WMO # RIV # River Gauge 9931 1319 Hunyani (Manyame ?) Mangula Mine Weir • • Hunyani and Manyame seem to be alternate names for the same river Hunyani seems to be the most common and current name • the gauge location has been variably identified as Mangula and Mangura in different sources; however, Mangula is near the given coordinates, while the place called Mangura is somewhat distant • • • • UNESCO data were limited to R1319 for 1980– Sep 1984 an independent source (IND) gives Nov 1964 – Sep 1984 IND and UNESCO agree on concurrent months the joint IND/UNESCO set is retained with the warning that pre-1980 data cannot presently be corroborated 106 Mazoe @ Lion's Den g/w ZW AF • • • • • WMO # RIV # River Gauge 9932 1320 Mazoe Lion's Den g/w UNESCO data were limited to R1320 for 1980–1982 and 1984 an independent source (IND) and GRDC summary data span Dec 1967 – Sep 1984 IND and UNESCO agree on concurrent months IND and GRDC summary data agree generally the joint IND/UNESCO set is retained Sabi @ Condo d/s g/w ZW AF WMO # RIV # River Gauge 9933 1323 Sabi Condo d/s g/w • • • • UNESCO data were limited to R1323 for 1955–1984 with missing months an independent source (IND) and GRDC summary data span the same period IND and UNESCO agree on concurrent months except for three errata in R1323 the GRDC annual averages and extrema are consistent with IND, and confirm the presence of errata in R1323 • R1323 has decimal shift typos in 1957 and 1973 • • May R1323 discharge = 207 is an error IND gives 20.7 • • Dec 1957 R1323 discharge = 904 is an error IND gives 90.4 • data from area rain gauges support IND; rainfall was normal or below normal • • Nov 1973 R1323 discharge = 422 is an error IND gives 4.22 • the joint IND/UNESCO set is retained with the corrections noted above 107 7.0 Asia Asia: China Note on Chinese River Names • • • • • the Chinese denote “river” by various suffixes appended to the proper names or as stand alone words, e.g., Changjiang = Chang Jiang = Chang River [the lower reach of the Chang is known locally as the Yangtze] -jiang (or -chiang, -kiang in certain older romanization schemes) implies geologically young rivers, i.e., rapid flowing, with steep canyons, etc. -he (or -ho in older romanization schemes) implies geologically old, broad, sluggish -shui indicates smaller streams, e.g., all the rivers and streams on Taiwan are -shui these suffixes are frequently omitted in technical discussions Changjiang @ Datong WMO # CN AS 9306 RIV # 903 River Gauge Changjiang Datong • • UNESCO sources give only 1976–1979 GRDC summary data and several independent sources (IND) give 1922–1988 with numerous missing years and months before 1950 • except for one typo, two independent sources agree; however, GRDC summary data have a few scattered discrepancies with other sources for which the particular months involved cannot be determined • GRDC summary data and one independent source (that may have been derived from GRDC records) have a typo in Jan 1985, they give discharge = 1,110 m3/s this is physically implausible; Dec 1984 and Feb 1985 discharges are 13,000+ m3/s one independent source from a Chinese institute gives 11,100 m3/s which is in the plausible range of Jan discharges for this gauge • • • Changjiang @ Hankou (Wuhan) WMO # CN AS 9305 RIV # 902 River Gauge Changjiang Hankou (Wuhan) 108 • • UNESCO sources give only 1976–1979 GRDC summary data and several independent sources (IND) give 1865–1987 with only a few missing months • different independent sources agree; however, GRDC summary data have a few scattered discrepancies with other sources for which the particular months involved cannot be determined • IND is retained Changjiang @ Yichang CN AS WMO # RIV # River Gauge 9357 1350 Changjiang Yichang • • • UNESCO sources give only 1980–1981 and 1983 one independent source (IND) gives 1877–1980 with only a few missing months an independent Chinese source gives 1980–1988 • • • • there is a discrepancy between W9357 and R1350 for Feb 1980, W9357 discharge = 3,720 for Feb 1980, R1350 discharge = 3,270 IND agrees with W9357 • the merged independent series is retained Dongjiang @ Boluo WMO # CN AS 9308 RIV # 900 River Gauge Dongjiang Boluo • • WMO and RIV have 1976–1982 an independent source has Sep 1953–1982 • • all agree on concurrent months IND is retained Huaihe @ Bengbu WMO # CN AS 9304 RIV # 904 River Gauge Huaihe Bengbu 109 • • • the Huai is one of the most heavily engineered rivers in the world there are 4,000+ control gates and 5,000+ dams most discharge passes into the lower Chang (Yangtze) system at Sanjiangying [32.32N, 119.72E]; rather than down the original direct channels to the sea • • • WMO and RIV have 1976–1979 GRDC summary data and an independent record (IND1) span 1915–1986 an independent Chinese source (IND2) gives 1980–1989 • data are exceedingly suspicious as should be obvious below; however, the unusual data represent periods of severe drought in 1978, the Huai largely dried up, and ca. 16 km3 water was transferred into the basin from the neighbouring Chang and Huang basins (Jiusheng, 1999). • 9304 9304 9304 9304 1976 1977 1978 1979 J F 277 0 130 0 495 0 155 0 M A M 607 206 431 0 237 1680 142 77 0 0 13.5 231 J J A S O N D mean 332 1030 763 678 24 31 17.5 152 1580 1950 583 665 568 205 63 350 104 0 0 0 0 0 1800 873 2700 1140 36.5 68.5 408 635 85 572 • IND1 agrees with UNESCO on the four concurrent years, and the GRDC summary data except for an obvious typo in GRDC (Feb 1916) • • • • IND2 disagrees with IND1 and GRDC for Mar 1981 IND2 gives 427 IND1 gives 472 & the GRDC annual average implies that GRDC must also give 472 Mar 1981 discharge of 472 is retained for the present Huanghe @ Sanmenxia / Shanxian WMO # CN AS CN AS 9303 10121 RIV # 901 River Gauge Area Huanghe Huanghe Sanmenxia Shanxian 688,421 687,869 • • Sanmenxia is a dam (completed in 1960) site near the city of Shanxian a discharge gauge has operated at Sanmenxia since about 1953 • an older gauge not far upstream known as “Huanghe @ Shanxian” operated from at least 1919 through 1958 • the areal difference between the two gauges is so small that the records can be patched together to form a long operational record 110 • • • • UNESCO sources give only 1976–1979 for Huanghe @ Sanmenxia an independent source (IND) gives 1919–1958 for Huanghe @ Shanxian and 1953–1988 for Huanghe @ Sanmenxia both gauges have 1953–1958 was data and 1954 is identical in both Sanmenxia & Shanxian records it’s not clear which gauge the data are for, but practically it makes no difference merging the two and averaging the 1953-1958 data make a long operational record • GRDC annual summary data for the two gauges span the same periods • the two Huanghe records are consistent with GRDC summary data, and Huanghe @ Sanmenxia is consistent with UNESCO records for 1976–1979 • the two records are retained with the W-series codes given above • Luanhe @ Luanxian CN AS WMO # RIV # River Gauge 9351 1344 Luanhe Luanxian Area 44,100 • • UNESCO sources give only 1980-1983 two independent sources, including the Chinese Institute of Atmospheric Physics in Beijing, span 1929–1987 and have the same data for 1980–1983 as found in UNESCO sources • exceedingly low 1980–1983 data deleted in previous revisions have been restored severe drought occurred 1980–1981, and abnormally low precipitation and discharges continued through 1987 (Chaoying et. al., 1999) • • the 1927–1987 data are retained • independent sources have an extreme Aug 1949 discharge of 2,400 that has been deleted of several rain gauge records available for the area to, none have 1949 data some may wish to restore the Aug 1949 discharge • • Songhua @ Haerbin WMO # RIV # River Gauge 111 CN AS 9302 924 Songhua Haerbin • • • UNESCO sources give 1976–1983 an independent source (IND) gives 1898–1983 (1949–1952 missing) GRDC summary data span 1898–1987 • on concurrent months these generally agree except for 4 large typos in GRDC that are scattered through the record • IND is retained Songhua @ Jilin CN AS WMO # RIV # River Gauge 9350 1343 Songhua Jilin • • UNESCO sources only give 1980–1983 an independent source (IND) gives 1933–1939, some months in 1944, 1954–1980, • GRDC summary data span 1933–1986 • there appears to have been a reservoir constructed in the 1940s at or not far upstream of this gauge • • there is reason to suspect all or part of 1981 do not belong to this gauge in the 1981 data given by all sources, Jan–Mar and Dec are the lowest observed since reservoir construction the Dec 1980 discharge was a strong 209 m3/s, and the abrupt drop to 49 m3/s in Jan 1981 seems improbable likewise, the reported Dec 1981 discharge of 51 is followed by 378 in Jan 1982 the 1981 mean annual discharge also stands out as a low outlier vis-à-vis the Songhua discharge at Harbin downstream the 1981 data may be another gauge, perhaps upstream of the Jilin reservoir • • • • 1933-1939 avg 1981 1954-1983 1954-1983 † • J F M A M 58 49 99 619 49 43 104 J J A S O N D mean 491 785 1,234 1,144 817 411 238 95 503 521 468 807 693 358 158 148 128 51 294 413 † avg 316 289 302 354 439 527 642 727 381 310 342 332 † min 122 104 119 144 226 263 212 183 115 111 110 117 excluding 1981 IND is retained (excluding 1981) 112 Xijiang @ Wuzhou 3 CN AS WMO # RIV # 9301 898 River Gauge Xijiang Wuzhou 3 • • • • UNESCO sources only give 1976–1983 an independent source (IND1) gives 1915 & 1941–1984 with some missing months an independent Chinese source (IND2) gives 1980–1986 GRDC summary data span the same period as IND1 • generally, these agree on concurrent months except for a significant typo in Dec 1981 UNESCO sources and GRDC give Dec 1981 discharge as 16,200 m3/s which is too high by ca. 10-fold the independent sources give 1,620 m3/s • • • GRDC summary data have scattered discrepancies with IND1 before 1980, including an obvious typo in 1942 • the joint IND1/IND2 series is retained Yongding @ Guanting CN AS WMO # RIV # River Gauge 9352 1345 Yongding Guanting • • UNESCO sources only give 1980–1983 an independent source (IND) gives 1925–1987 with some missing years • • • • R1345 has a typo for Dec 1980, R1345 discharge = 1.5 the others give 15.5 the lowest Dec discharge for 50 years of record is 9.9 • • IND has an extraordinarily high discharge for Jul 1939 of 578 m3/s this is supported by rain gauge data • IND is retained 113 Yujiang @ Nanning CN AS • • • WMO # RIV # River Gauge 9359 1352 Yujiang Nanning UNESCO sources only give 1980–1983 an independent source (IND) gives 1936–1938 and 1947–1984 with some missing months IND agrees on concurrent years but cannot be corroborated beyond 1976-1983 at present Asia: India / Bangladesh Brahmaputra @ Bahadurabad BD AS • • • WMO # RIV # River Gauge 9270 Brahmaputra Bahadurabad 865 Area UNESCO Fekete et al. 636,130 554,542 the UNESCO / GRDC drainage area for this gauge is too large the total Brahmaputra basin area is usually given as ca. 580,000 km2 the estimate by Fekete et al. is accepted River Ganges (Ganga) WMO # IN AS BD AS 9227 9271 RIV # 863 864 River Gauge Ganges Ganges Farakka Paksey Area 951,600 846,900 • IHD, W9227 and R863 data for Farakka are identical were they overlap • since 1975, the Farakka barrage has diverted waters down the Bhagirathi–Jangari– Hooghly distributary to maintain water levels for dry season shipping in River Hooghly past Calcutta • nearly all available records should be for pre-Farakka diversion times • W9271 and R864 records for Paksey agree over 1969–75 • for 1965–67, R864 contains Farakka data • these Farakka data were deleted from the present Paksey record • the Paksey gauge is likely defunct • sometime since 1975, a Bangladeshi record for Ganges @ Hardinge Bridge begins 114 • if available coordinates are correct, Hardinge Bridge is so close to Paksey that differences between the two should be negligible Drainage Areas • the drainage areas for Farakka and Paksey should not be taken too seriously • the effective drainage area for Farakka will be less than the true drainage area due to the natural flow down the Hooghly distributary • the effective drainage area for Farakka has been even smaller since the diversion • a drainage area of 935,000 km2 is sometimes reported for Ganges @ Farakka; this may be the effective basin area, but could be just another ad hoc estimate • between Farakka and Paksey, there is some local inflow, but sizable distributaries lead off the Ganges both to the north toward the lower Brahmaputra and to the south to the Bay of Bengal • the given drainage area for upstream of Paksey is smaller than Farakka • this may be a deliberate estimate of the effective drainage area, or maybe just another ad hoc estimate • on 47 common months of record, the mean Paksey discharge is 4.6% higher than the mean discharge at Farakka — a net gain that is probably within the margin of error associated with the discharge measurements Asia: India Bhima @ Yadgiri / Krishna @ Devarsugur (Deosugur ?) IN AS IN AS WMO # RIV # River Gauge 9263 9262 1272 840 Bhima Krishna Yadgiri Devarsugur • the correct name for this gauge is very likely Devarsugur not Deosugur as given in UNESCO files • • Bhima @ Yadgiri has 1971–1979 Krishna @ Devarsugur has 1971–1974 • R840 Krishna @ Devarsugur has incorrectly appended the 1976–1979 data for Bhima @ Yadgiri the correct location for the 1976–1979 data is obvious as Krishna @ Devarsugur has discharges about 3-fold higher than Bhima @ Yadgiri • 115 • the site has to be downstream of Krishna @ Almatti and above the confluence with the Bhima Brahmani @ Barakot Bridge WMO # IN AS • • • • • RIV # 9255 861 River Gauge Brahmani Barakot Bridge WMO and RIV give only 1971 and 1972 the 1972 discharges are larger than those in the Ganges for 1972 the drainage area is not given, but is roughly 15,000–25,000 km2 the 1972 data may be for another river or, may have been mis-scaled by a decimal shift, or may still be in imperial units the 1972 data were removed from the present set 1971 1972 J F M A M 36 1740 33 1477 27 932 30 772 39 587 J J A S O N D mean 898 1646 3049 1724 1169 24084 44856 21930 436 6326 114 3727 61 2313 671 9014 Cauvery River Gauges WMO # RIV # River Gauge Lat Lon AS AS IN IN 9266 1433 1263 Cauvery Cauvery Grand Anicut (North) Grand Anicut (South) 12.62 10.83 76.10 78.83 AS IN 9265 837 Cauvery Krishnarajasagar 12.42 76.58 • • • • • • • R1433 has no data that are not fragments of records from R1263 and R837, except for 1974 (see below) which seems to be an orphan R1433 was deleted the 1974 record for W9266 is suspect and was deleted this fragment is found in W9266, and in RIV for the dubious site record R1433 historical patterns show that strong wet monsoon discharges upstream at Krishnarajasagar imply strong flows downstream, with some lag and attenuation annual mean discharge at Grand Anicut is always greater than at Krishnarajasagar the 1974 record for W9266 seems to be an orphan pasted into the wrong place J F M A M J 116 J A S O N D Mean • • • 9266 1971 1974 1976 1977 1978 1979 196 39 263 133 375 321 125 25 255 5 193 225 31 5 8 2 106 33 12 3 9 6 12 26 17 10 8 4 4 5 7 40 1 2 2 180 615 17 37 198 351 504 400 27 370 523 745 645 670 39 241 368 673 573 428 45 119 341 432 638 316 40 84 442 512 721 326 27 6 113 347 339 262 26 117 178 313 351 9265 1971 1974 1976 1977 1978 1979 5 9 1 1 3 24 4 9 1 1 1 4 1 2 1 2 6 12 3 2 4 10 8 2 15 13 6 41 49 8 447 9 9 123 290 93 478 345 647 789 193 330 536 364 609 1090 390 945 194 211 168 255 370 198 164 123 23 375 135 108 50 13 62 153 41 99 36 13 8 33 27 35 145 153 67 158 219 160 coordinates for W9266 / R1263 locate the site near the head of the delta on a distributary channel that would not necessarily represent all discharge from the Cauvery into the delta reports on peninsular Indian surface runoff usually cite the gauge at Museri just upstream of the delta with drainage area 66,000 km2 and mean annual discharge of 11.5 km3 (364 m3/s) to the early 1980s or so — that is somewhat higher than the mean of 264 m3/s for the 5 good years at site W9266 which has nominally higher drainage area (74,000 km2) anicut is the Tamil word for dam Indrawati @ Parthgudem WMO # RIV # River Gauge IN AS 9259 857 Indrawati Parthgudem IN AS 9260 859 Kolab Kotta • • • WMO and RIV have 1971–1979 1977–1979 of W9259 are data for W9260 Kolab @ Kotta R857 has the correct data Kalinadi @ Dundeli IN AS • • • WMO # RIV # River Gauge 9250 1258 Kalinadi Dundeli UNESCO sources have 1968–1979 1972 and 1973 are identical in both WMO and RIV it is unclear which year is correct 117 • 1973 was arbitrarily deleted — this may be wrong, but won’t affect basic annual and seasonal summary statistics Asia: Iran • the -suffix “rud” or word “Rud” appended to many river names is a short form for the longer Iranian word for river, e.g., Shafarud, Shafa-rud, or Shafa Rud all mean Shafa River WARNING — Questionable Data Quality • • • • • the available data are not the best quality the UNESCO data agree except for a few typos as all versions almost surely originated from the same source files however, for several sites, there are numerous discrepancies between UNESCO records and concurrent data from independent sources there are no compelling reasons to believe that any given source is more reliable than the available alternatives discrepancies between UNESCO records and alternate data from independent sources for the first three sites listed below likely represent some combination of data entry errors, historical revisions and muddling of data from other gauges on the same or adjacent streams WMO # RIV # River Gauge IR AS IR AS IR AS 9221 9217 9219 119 110 112 Gorgan Minab Shafa Gonbad-e Qabus Berantin Poonel IR AS IR AS 9222 9224 108 822 Karun Karun Ahvaz Pol-e-Shalu WARNING — Time-Shift 1980–1984 !!!! • 1980–1984 data in UNESCO sources (WMO, RIV) and GRDC summary data are almost surely on a local water year basis (back-shifted 9 months) for the sites listed below 118 • before 1980, data at these sites and other Iranian sites with no data after 1980 are time-indexed correctly in UNESCO files WMO # RIV # River Gauge 9221 9347 9222 9346 9216 9217 9219 9345 9344 119 1356 108 Gorgan Halil Karun Kor Kor Minab Shafa Zayandeh Zayandeh Gonbad-e Qabus Hossein Abad Jiroft Ahvaz Ahmadabad Ahmadabad Drudzan Berantin Poonel Pol-e-Kaloh (Pol-e-Kaleh) Pol-e-Khaju IR IR IR IR IR IR IR IR IR AS AS AS AS AS AS AS AS AS • the effect of the time-shift on the seasonal patterns are shown below for the Gorgan River which has data indexed correctly to calendar years for 1965–1976 the seasonal peak discharges are shifted 3 months from Mar–May to Jun–Aug the corrected Oct 1980 – Sep 1985 data have a seasonal cycle that closely matches • • • 109 110 112 1353 1355 for most of Iran seasonal peak discharges are expected to occur from Mar–May with the melting of winter snow and spring rain 30 25 Gorgan River (Rud), Iran m^3/s 20 15 10 5 0 J F M A 1965-75 • M J J 1980-85 corrected A S O N D 1980-84 UNESCO in the present compilation, 1980–1984 Iranian data have been indexed correctly Ghezalozan (Qezel Owzan) @ Gilvan WMO # RIV # River Gauge 119 IR AS 9223 814 Ghezalozan Qezel Owzan Gilvan • the common modern transliterations of the this river name are Qezel Owzan or Qezel Uzan; less commonly Qizil Owzan or Qizil Uzan • • • • UNESCO sources have only 1976–1979 an independent source (IND) gives 1965–1985 UNESCO and IND are identical on concurrent months IND is retained Halil @ Hossein Abad Jiroft IR AS WMO # RIV # River Gauge 9347 1356 Halil Hossein Abad Jiroft • • • • UNESCO sources have only Oct 1980 – Sep 1985 an independent source (IND) gives 1965–1985 UNESCO and IND are identical on concurrent months IND is retained • Warning: data are highly variable and cannot presently be corroborated before Oct 1980 Karkheh (Al Karkha) @ Hamidiyeh WMO # IR AS • • • • • RIV # 9225 River Gauge Karkheh (Al Karkha) Hamidiyeh the Karkheh is known as the Al Karkha in Iraq where it joins the Tigris WMO has only 1976 – 1979 an independent source (IND) gives scattered months for 1948–1956 and 1965– 1985 UNESCO and IND are identical on concurrent months IND is retained Karun @ Ahvaz / Pol-e-Shalu WMO # RIV # River Gauge Area IR AS 9222 108 Karun Ahvaz 60,769 IR AS 9224 822 Karun Pol-e-Shalu 22,913 120 • for Karun @ Ahvaz: • W9222 gives 1965–1975 with some missing months and 1980–1984 • R108 gives 1965–1984 with some missing months • R108 has 1976–1979 data that are not in W9222 and are not for Ahvaz • an independent source has 1894–1956 and 1965–1985 • upstream at Karun @ Pol-e-Shalu: • W9224 and R822 identically give 1976–1979 • an independent source has 1965–1985 • inconsistencies are rampant amongst these series • • • 1976–1979 data given by R108 are not for Karun @ Ahvaz (see figure) this is likely not a scaling problem these 1976–1979 data are more likely from a site upstream of Karun @ Pol-eShalu with roughly 1/2 the drainage area 3000 Karun River, Iran Ahvaz_IND Ahvaz R108 Pol-e Shalu W9224 2500 m3/s 2000 1500 1000 500 0 1976 1977 1978 1979 1980 Figure xx. Karun River 1976–1980 data for Ahvaz (IND and R108) and W9224 (Pol-e-Shalu) • the 1976–1979 data from R108 are listed below on the chance that someone may know where they belong R108 1976 J F M A M J J A S O N D 294 518 363 638 505 204 102 60 47 61 82 101 121 R108 R108 R108 • • • • • 1977 1978 1979 139 240 142 192 228 409 248 400 251 308 270 326 126 113 179 67 57 61 26 39 57 28 30 47 24 36 36 30 41 35 134 39 53 215 243 107 for Ahvaz, IND and W9222 agree exactly only on 1980–1985 there are numerous discrepancies on concurrent months from 1965–1975 these are mostly small, but some are large, e.g., Jan–Mar 1969 for Jan 1969 IND gives 519 and W9222 gives 1700, etc. data for Pol-e Shalu upstream, suggest that it is W9222 that may be in error, but Pol-e Shalu represents only 25% of the Ahvaz drainage area 3500 3000 2500 2000 1500 1000 500 0 1965 1966 1967 1968 1969 1970 Ahvaz_IND 1971 1972 1973 1974 1975 Ahvaz W9222 Records Retained • • joint UNESCO / IND records are retained for both WARNING: some data for these sites may be unreliable Kor @ Ahmadabad / Kor @ Ahmadabad Dorudzan WMO # IR AS IR AS 9346 9216 RIV # 109 River Gauge Kor Kor Ahmadabad Dorudzan 122 Lat Lon El Area 30.23 52.33 30.21 52.42 2,170 1,610 4,830 5,100 • the Kor River lies in a closed interior basin of the Zagros mountain range in south central Iran • the 9 month back-shift of 1980–1984 data in raw W9346 and R109 records was corrected before proceeding • • metadata and data at these sites are muddled the metadata given above are the best guess at the situation from the available information WARNING: these records may not have been labelled correctly • • WMO, the GRDC catalogue, and an independent source (IND) all indicate that there are two gauges labelled Ahmadabad and Ahmadabad Dorudzan; however, coordinates and drainage areas are inconsistent, i.e., the site the larger drainage area is located upstream of the one with smaller drainage area • the correct name for Ahmadabad Dorudzan may be Sadd-e Dorudzan (Dorudzan dam) or simply Dorudzan NIMA gives coordinates for Dorudzan that fall on the river • • coordinates given for Ahmadabad are just a guess; NIMA gives coordinates for 6 places (at least) called Ahmadabad in the general vicinity; of these, about four lie near the Kor River channel — one is upstream and three are downstream of Dorudzan Data • the data contained in these sources comprise three fragments: 1) 1965–1971 2) Jan 1973 – Aug 1975 3) 1980–1985 — in IHD, W9216, R109, and IND — in R109 and IND — in W9346, R109 and IND 123 100 90 80 Kor River, Iran 70 60 50 40 30 20 10 19 64 19 65 19 66 19 67 19 68 19 69 19 70 19 71 19 73 19 74 19 75 19 76 19 77 19 78 19 79 19 80 19 81 19 82 19 83 19 84 19 85 0 R109 W9216 W9346 • R109 comprises all three fragments, but on the plot above, for illustrative purposes, only the unique Jan 1973 – Aug 1975 fragment is indicated as R109 • the 1965–1971 and 1980–1985 fragments as given in W9216 and W9346 seem to represent distinct gauges; the 1980–1985 data have lower mean level and different seasonal characteristic the Jan 1973 – Aug 1975 fragment has mean level like W9216 and seasonal like W9346 however, these fragments are too short to indicate confidently whether these records represent the same or different gauges • 45 40 Kor River, Iran 35 30 m^3/s • 25 20 15 10 5 0 J F M A M J w9216 Ahmadabad 1965-71 124 J A S w9346 Doruzdan 1980-85 O N D • for the present set data are retained as: 1) 1965–1971 and 1973–1975 fragments are collated in W9216 under the label Kor @ Dorudzan which is assumed to be downstream of Ahmadabad 2) 1980–1985 are maintained under 9346 under the label Kor @ Ahmadabad which is assumed to be upstream of Dorudzan • this arrangement may be wrong Lar @ Ploor WMO # IR AS • • • • RIV # 9218 111 River Gauge Lar Ploor UNESCO sources have 1965–1975 with some missing months an independent source (IND) has 1946–1975 with some missing years and months on concurrent data UNESCO and IND agree the joint IND/UNESCO set is retained with the warning that pre-1965 data could not presently be corroborated Minab @ Berantin WMO # IR AS • • • • • • • • • RIV # 9217 110 River Gauge Minab Berantin UNESCO sources have 1965–1971, 1973–1975 and 1980–1985 with missing months two independent sources (IND1 and IND2) give 1962–1985 with scattered missing months and years UNESCO and IND1 mostly agree on concurrent months IND2 disagrees frequently with these from 1967–1975, but the mean level is about the same the joint IND1/UNESCO set is retained the IND1 part of the record should be treated with due caution 1976–1979 IND1 data have some extraordinarily high discharges these may be legitimate as rainfall in this desert area is highly variable so that occasionally very wet years are encountered there is a rough correspondence with the sequence annual mean levels observed further north at Halil @ Hossein Abad Jiroft; hence, IND1 data were retained Shafa @ Poonel 125 WMO # IR AS • • • 9219 RIV # River Gauge 112 Shafa Punel (Poonel) the Shafa is a small stream in the narrow coastal lowland margin of the southwestern Caspian Sea which has its own relatively wet microclimate with mean annual precipitation exceeding 1 m this local climatic zone extends roughly from 39N on the west side of the Caspian Sea in southeastern Azerbeijan around to ca. 50E on the south side in Iran the Shafa streamflow record will likely compare well only with other small streams in the immediate area • UNESCO sources have 1965–1971, 1973–1975 and 1980–1985 with missing months • • • an independent source (IND) has Oct 1956 – Sep 1985 on concurrent years, IND and UNESCO agree only for 1980–1985 before 1980, on 111 concurrent months from 1965–1975, there are ubiquitous discrepancies between IND and UNESCO the two records may represent different streams with similar mean discharge level and seasonal patterns, or one of the records may have been revised significantly • • as there are no other records from the immediate vicinity to offer corroborative evidence, the IND data were discounted, but the problems may lie with the UNESCO data • with one exception noted below, UNESCO records are retained “as is” with the warning that the pre-1980 data may be for a different stream • if UNESCO records are indeed Shafa @ Punel, all (IHD, WMO and RIV) likely have a typo in Oct 1967 all give Oct 1967 discharge = 80 which is abnormally high and is not supported by precipitation data from a nearby gauge Oct 1967 was set to missing • • Zayandeh @ Pol-e Khaju / Pol-e Kaloh (Pol-e Kaleh ?) IR AS IR AS • • • WMO # RIV # River Gauge 9344 9345 1355 1353 Zayandeh Zayandeh Pol-e Khaju Pol-e Kaloh (Pol-e Kaleh ?) for these two, UNESCO has only 1980–1985 an independent source gives data for 1965–1985 records agree on concurrent years 126 Area 14,320 5,650 • the joint IND/UNESCO records are retained at each site with the warning that pre1980 data could not presently be confirmed Asia: Japan Warning: Bad UNESCO/GRDC data some years (1960, 1965, 1966) • • several of these records have the wrong data inserted for 1960, 1965 and 1966 generally, the dubious data are much higher than, or in one case, much lower than expected Ishikari @ Ishikari-Ohashi WMO # JP AS RIV # 9333 173 River Gauge Ishikari Ishikari-Ohashi • • UNESCO sources give 1954–1984 an independent Japanese source (IND) gives 1975–1995, but is missing 1976, 1978 and 1982 • • • there is an unusual columnar replication error of Jan-Feb data for 1954–1959 the error is common to IHD, WMO and RIV these were deleted 1954 1955 1956 1957 1958 1959 1960 1961 • • • • J F M A M J J A S O N D 201 201 90 247 247 195 119 215 201 201 90 247 247 195 111 228 284 499 272 267 344 329 127 291 1761 1432 1413 1615 1354 1186 196 1431 1004 795 935 1019 837 422 294 1002 386 417 491 348 386 328 112 255 253 661 359 264 454 318 108 695 885 842 596 535 618 271 276 321 450 490 299 828 329 469 256 446 339 751 324 707 348 300 164 250 420 687 428 389 304 309 173 321 472 402 275 381 309 431 174 294 1960 discharges are abnormally low precipitation was somewhat lower than in 1959 and 1961; however, there was a protracted drought from 1982–1986 with much lower precipitation during which mean annual discharge never fell below 300 m3/s hence, there are strong reasons to believe that the 1960 record belongs to another gauge accordingly, the 1960 record was deleted 127 1958 1959 1960 1961 1962 • J F M 119 215 145 111 228 276 344 329 127 291 162 M J 1,354 837 1,186 422 196 294 1,431 1,002 1,531 521 386 328 112 255 362 J A S O N D mean 454 618 318 271 108 276 695 321 272 1,426 329 469 256 446 602 348 300 164 250 401 304 309 173 321 345 309 431 174 294 335 528 436 176 479 532 within rounding limits, IND agrees with UNESCO data except for Nov–Dec 1975 IND 1977 9333 1977 • A J F 203 203 198 198 M A M J J A S O N D 405 1,127 1,324 405 1,128 1,323 363 363 255 255 415 416 319 319 255 255 461 422 335 455 the joint UNESCO/IND series for 1954–1995 was retained with the IND version for 1977 Chikugo @ Senoshita WMO # JP AS 9334 RIV # 168 River Gauge Chikugo Senoshita • • UNESCO sources give 1965–1984 (1975 missing) independent Japanese source (IND) gives 1950–1994 • except for 1966, IND agrees with UNESCO within rounding limits • 1966 data in UNESCO sources (IHD, WMO, RIV) are from a much larger river, not from this gauge the largest annual mean discharge in 45 years at site 9334 is only 208 m3/s also UNESCO gave erroneous 1966 discharges at two other Japanese sites • • J F M A M J J A S O N D Mean UNESCO 1966 92.0 81.0 476.0 121.0 171.0 449.0 641.0 146.0 617.0 128.0 210.0 62.0 266.2 IND 1966 40.2 51.1 133.3 Senoshita mean 50.3 62.4 • 87.1 61.7 37.0 134.5 69.8 63.4 46.7 80.3 101.6 111.4 214.0 295.5 132.3 130.5 80.5 55.4 48.2 113.5 IND was retained 128 86.7 120.9 77.7 Shinano @ Ojiya WMO # JP AS • • • • • • • • 9335 RIV # 171 River Gauge Shinano Ojiya UNESCO sources give 1965–1984 (1975 missing) independent non-Japanese source (IND) gives 1953–1985 (1960 and 1964 missing) GRDC summary data span 1965–1988 UNESCO and IND agree except for 1965 and 1966 when UNESCO/GRDC data almost surely are from another gauge on a much bigger or wetter river the respective mean annual discharges for 1966 and 1965 as given by UNESCO would be the 1st and 3rd highest on record two precipitation gauges in the basin had only marginally wetter than normal years also the neighbouring rivers [Yodo @ Hirakata, Tone @ Kurihashi] remained at near normal levels for 1965 and 1966 also UNESCO gave erroneous 1966 discharges at two other Japanese sites J F IND 1965 9335 1965 286 526 274 489 IND 1966 9335 1966 332 382 367 769 823 780 2444 1319 • M A M 302 633 951 485 1042 1329 J J A S O N D mean 645 792 903 1130 300 353 507 609 262 289 489 627 466 556 492 695 255 489 440 1887 379 538 370 693 360 435 488 1111 577 564 576 817 2300 1298 a joint IND/UNESCO series is accepted with IND data for 1965 and 1966 Tone @ Kurihashi WMO # JP AS 9331 RIV # River Gauge 172 Tone Kurihashi • • • UNESCO sources give 1938–1984 (1947, 1975 missing) independent non-Japanese source (IND) gives 1938–1984 (1947 missing) UNESCO and IND agree on concurrent months • all sources show extremely high runoff for Apr–May 1960 that may be typographical errors Apr-May discharges exceed by 2-fold the highest recorded in all other years Jan–Feb runoff are also the highest on record, and identical • • 129 • a few sparse precipitation gauges show neither unusual winter nor spring precipitation; 1960 was marginally drier than the 1959 and 1961 9331 1960 avg J F 195 108 M A M J J A S O N D mean 195 305 1093 1036 443 238 275 274 221 266 327 406 109 143 285 375 372 448 329 192 142 249 249 240 • also 1960 is missing from a non-Japanese independent source for the three Honshu rivers (Shinano, Tone, and Yodo), i.e., there is reason to suspect that 1960 data from another river were inadvertently pasted into the Tone River record to fill a missing year • there is good reason to believe that Jan, Feb, Apr, May, and possibly all 1960 data are in error • IND is retained without 1960 Yodo @ Hirakata WMO # JP AS 9332 RIV # River Gauge 170 Yodo Hirakata • • • UNESCO sources give 1965–1984 (1975 missing) an independent non-Japanese source (IND) gives 1953–1988 (1960, 1964 missing) GRDC summary data span 1965–1988 • sources generally agree on concurrent months except for 1966 when UNESCO data are from a gauge with ca. 2-fold larger discharge in five months, discharges exceed the maxima observed in 32 other years these nominal discharges are ca. 2-fold higher than 1965 given the high degree of regulation imposed upstream by Lake Biwa which controls half the watershed above Hirakata, it is highly implausible that discharges doubled from 1965 to 1966 UNESCO also gave erroneous 1966 discharges at two other Japanese sites • • • • J F M A M J J A S O N D mean 9332 1966 336 500 1104 365 703 863 1810 483 887 336 180 285 654 IND 1966 270 273 543 237 310 416 539 199 313 199 147 184 303 mean 183 205 235 302 279 392 531 283 352 228 152 157 275 32 yrs † 130 32 yrs † † max 303 461 353 580 610 870 1080 954 989 534 340 260 417 not including 1966 • IND was retained Asia: Korea, North North Korea: Six sites with additional data not in UNESCO files • • • • KP KP KP KP KP KP for the six gauges below, UNESCO files generally have data from 1976 to 1981– 1984 an independent source gives additional data back to 1964–1966 on concurrent months IND and UNESCO agreed except for a few scattered discrepancies that usually appeared to be typos in IND the joint IND/UNESCO set has been retained with the warning that the pre-1976 data may have scattered typos AS AS AS AS AS AS WMO # RIV # River Gauge 9316 9321 9319 9317 9318 9320 925 1255 918 914 919 1254 Amnok (Yalu) Biryu Nam Taedong Taedong Zangza Kumchang Songchon Samdung Mirim Dokchon Jonchon Asia: Malaysia Malaysia: General Remarks • if the opportunity arises, data for Malaysia rivers should retrieved directly from Malaysian sources • data in UNESCO files and other indirect sources are riddled with missing values and enough discrepancies to cast doubt on their validity (the risk mostly seems to 131 be that data have been muddled across sites, or are provisional or other early data releases that have since been revised) • the best quality record is Johor @ Rantau Panjang which came directly from a source inside the agency responsible for discharge monitoring, but this too may have been revised since this record was prepared in the early 1990s Johor @ Rantau Panjang WMO # MY AS RIV # River Gauge 92 Johor Rantau Panjang 9288 • • W9288 gives 1969 and 1973–1985; R92 is missing some of these years an independent Malaysian source gives 1963–1991 • there are discrepancies between WMO and RIV over 1976–77, and between these • • 1976–77 data for R92 seem to be from another gauge other sporadic discrepancies may be typos or data that have since been revised • J F M A M J J A S O N D IND 1976 WMO 1976 RIV 1976 11 10 21 4 4 8 9 - 12 - 20 38 15 15 30 18 18 35 15 15 30 14 14 28 40 41 72 36 35 55 56 60 98 IND 1977 WMO 1977 RIV 1977 67 63 96 30 32 56 17 15 30 8 8 18 20 20 39 24 24 46 16 16 33 23 24 45 26 27 49 59 58 96 56 56 93 30 62 IND 1978 WMO 1978 RIV 1978 66 66 66 19 19 19 27 27 27 35 35 35 51 51 51 19 19 19 36 36 36 17 17 17 17 18 18 19 22 22 51 52 52 93 68 68 IND 1979 WMO 1979 RIV 1979 50 49 49 22 22 22 31 31 31 60 60 60 24 23 23 25 25 25 23 24 24 21 21 21 36 36 36 22 22 22 124 133 133 56 52 52 IND was retained Kelantan @ Guillemard Bridge WMO # RIV # River Gauge 132 MY AS 9336 154 Kelantan Guillemard Bridge • • UNESCO sources have data from 1949–1986 with numerous missing months IHD has a few months not WMO and RIV (Oct 1966, Feb, Dec, 1967) • an independent non-Malaysian source (IND) gives some scattered data that include 1987–1988 and some months in 1989–1990 on concurrent months, IND agrees with WMO 1987–1990 data not concurrent with WMO look typical but cannot presently be corroborated • • • • • except for a few months, 1973–75 of R154 are not from the Guillemard Bridge gauge as shown below Dec 1973 and Jan 1975 peak discharges in W9336 correspond to high rainfalls in northeastern peninsular Malaysia during those months [Dec 1973 rainfall was near the highest on record] it’s unclear what the 1973-1975 fragment of R154 represents 4500 wmo 9336 riv 154 4000 3500 m3/s 3000 2500 2000 1500 1000 500 0 1970 • RIV 1971 1972 1973 1974 1975 1976 1977 1978 1979 the record fragment from R154 is below for anyone that wants it 1973 1974 1975 J F M A M J J A S 630 570 136 300 410 533 180 250 353 140 420 283 220 480 437 310 290 316 260 391 326 280 295 271 450 442 532 133 O N D 500 650 345 540 756 715 466 1276 1361 • • the record retained is a composite of W9336, a few months from IHD, and 1987–1990 data from IND the 1987–1990 data should be used with due caution Krian @ Dusun Limai MY AS WMO # RIV # River Gauge 9282 1293 Krian Dusun Limai • • UNESCO sources all give just one year of data, nominally labelled 1969 an independent non-Malaysian (IND) source gives 1961–1972 • the UNESCO data labelled 1969 occurs as 1968 in the IND record • IND is retained Langkat @ Dingkil WMO # MY AS RIV # 9286 98 River Gauge Langat Dingkil • • W9288 gives 1969 and 1973–1985; R92 is missing some of these years an independent non-Malaysian (IND) source gives mostly the same data as UNESCO plus 1961–1968 and scattered entries for 1986–1990 • • WMO and RIV agree except in 1975 when RIV seems to be from another gauge R98 is suspicious because rainfall data suggest that discharge should have risen Feb-Apr and Jul–Sep 1975 of R98 was discarded 1975 of W9286 was retained as given • • 1975 1 1975 2 1975 3 1975 4 1975 5 1975 6 1975 7 1975 8 1975 9 1975 10 1975 11 1975 12 W9286 R98 dif %dif 38.2 41.6 51.5 79.8 30.2 35.4 18.0 - 20.0 20.0 23.5 28.5 21.5 20.5 31.0 18.5 19.0 14.5 - 18.2 21.6 28.0 51.3 62.5 70.1 74.7 94.7 11.7 16.4 3.5 48.0 60.3 21.5 134 • • • compared to the UNESCO block, IND data from 1961–1968 have somewhat higher discharges, while IND data from 1986–1990 have some lower discharges this stream is so small and potentially variable that the IND data not in UNESCO are all plausible the record retained is a composite of WMO with IND data for 1961–1968 and 1986– 1990; these should be used with due caution Pahang @ Temerloh WMO # MY AS 9281 RIV # 107 River Gauge Pahang Temerloh • • UNESCO sources give 1965–1969, 1973–1984 an independent source (IND) has most of the above plus fragments of 1963–1964, • the joint UNESCO / IND record is retained • N.B. the exceptionally high Dec 1970 discharge = 3540 given by IND is substantiated by rain gauge records; Dec 1970 rainfalls at a few gauges in the basin were at or near the highest observed in a long historical record Perak @ Iskandar Bridge WMO # MY AS 9283 RIV # River Gauge 153 Perak Iskandar Bridge • • UNESCO sources give 1965–1969, 1973–1985 an independent source (IND) has most of the above and fragments for 1963–1964, • the joint UNESCO / IND record is retained Selangor @ Rantau Panjang WMO # MY AS 9287 RIV # 97 River Gauge Selangor Rantau Panjang 135 • • UNESCO sources give 1969, 1973–1984 an independent source (IND) has most of the above, and fragments for 1961–1968, • the joint UNESCO / IND record is retained Sembrong @ Brizay Bridge MY AS WMO # RIV # River Gauge 9289 1291 Sembrong Brizay Bridge Area 186 • • UNESCO sources give 1969, and 1975–1985 with many missing months an independent source (IND) has the above, plus some months in 1970–1972 • the joint UNESCO / IND record is retained Trengganu @ Kampung Tanggol WMO # MY AS 9284 RIV # 104 River Gauge Trengganu Kampung Tanggol • • UNESCO has 1969 and 1973–1985 with many missing months an independent source (IND) has these, 1961–1967, and scattered months in 1970, • GRDC annual summary data span 1969–1987 • • GRDC generally agrees with WMO except for Dec 1973 when the W9284 discharge of 1,987 m3/s was replaced with 608 rain gauge data show Dec 1973 rainfall was at or near record highs in the area, and perceptibly higher than the Jan 1975 rains that generated discharge of 1,045 m3/s Dec 1973 W9284 discharge of 1,987 m3/s appears to be far more valid than 608 • • • WMO and RIV agree except for 1975 (see below) when W9284 is higher than R104 the difference amounts to ca. 1.2 km3 water in total for 1975 discrepancies are relatively most significant for low flows • • there appears to have been a system corrective adjustment more IND data agree with WMO which are assumed to be correct for present purposes • 1975 1 9284 104 dif %dif 1,045 993 52 5.1 136 1975 2 1975 3 1975 4 1975 5 1975 6 1975 7 1975 8 1975 9 1975 10 1975 11 1975 12 330 231 168 195 180 160 112 165 182 686 722 288 191 134 158 144 127 86 133 146 636 673 42 40 34 37 36 33 26 32 36 50 49 13.6 19.0 22.5 21.0 22.2 23.0 26.3 21.5 22.0 7.6 7.0 1200 1000 800 600 400 200 74 07 74 08 74 09 74 10 74 11 74 12 75 01 75 02 75 03 75 04 75 05 75 06 75 07 75 08 75 09 75 10 75 11 75 12 76 01 76 02 76 03 76 04 76 05 76 06 0 w9284 • • r104 a joint WMO / IND data set has been retained these data do not inspire great confidence and should be used cautiously Asia: Mongolia General Remarks WMO # RIV # River Gauge MN AS MN AS MN AS 9313 9314 9315 892 894 896 Delgermuren Orkhon Tola Muren (Moron ?) Orkhon Ulan-Bator MN AS MN AS MN AS 9311 9312 9310 905 885 893 Kerulen Kobdo Selenga Undurkham (Ondorhaan) Ulgi (Olgiy) Chutic 137 • • • • three Mongolian records (yellow-shading) had additional, generally older (19451957) data in the Arctic drainage set at R-Arcticnet the other three are as found in UNESCO files metadata for some gauges in UNESCO and R-Arcticnet were somewhat crude finding these places in gazetteers and maps can be difficult as there is little consistency to the English transliterations of Mongolian place names Asia: Pakistan Indus @ Attock / Kotri WMO # RIV # River Gauge km2 PK AS 9273 849 Indus Attock 265,122 PK AS 9275 831 Indus Kotri 832,418 975,000 • • • UNESCO sources have 1973–1979 for both gauges an independent source (IND) gives 1936–1956, 1967–1971, and 1973–1979 for both gauges IND and UNESCO agree on concurrent months • the joint IND/UNESCO sets are retained Bad drainage area: Kotri • • • • • • • the drainage area for Kotri given in all available sources [ which all give the same figure that appears to derive from an old report of the 1960s ] is wrong Kotri is the site of an irrigation diversion barrage located at the head of the Indus delta the drainage area at the Sukkur barrage located somewhat upstream of Kotri is given as 900,000 km2 the area of the delta is variably given as 6,000–8,000 km2 the area of the entire Indus basin is variably given as 916,000–1,200,000 km2 with a mean of 1,000,000 km2 for 22 estimates 6 more recent digitally-derived estimates put the Indus drainage area as 1,000,000– 1,145,000 km2 for the present, the drainage area of the Kotri gauge is conservatively taken as 975,000 km2; however, if the most recent digital estimations are correct, the Kotri drainage area is likely 995,000 km2 or more 138 Warning: declining Indus discharge • • • • since independence, Pakistan has constructed one of the world’s largest irrigation systems accordingly, discharge through the mid to lower reaches of the Indus has fallen dramatically the average number of days per annum when no water reaches the sea has risen from 0 in 1960 to 85 in the 1990s [World Commission on Dams report on Ecosystems and Large Dams] mean annual discharge at Kotri has fallen from ca. 90-100 km3 to 40-45 km3 Asia: Philippines Cagayan @ Pangal / Palattao WMO # PH AS PH AS • • • RIV # 9290 9294 159 160 River Gauge Area Cagayan Cagayan Pangal Palattao 4,244 4,341 IHD and WMO gave 1969–1974 for Cagayan @ Pangal and only 1976 for Cagayan @ Palatto RIV gave the same data, but has reversed the metadata IHD and WMO being consistent are assumed to be correct Pampanga @ San Agustin, Arayat WMO # PH AS RIV # 9916 158 River Gauge Pampanga San Agustin, Arayat • • IHD / R158 have 1969–1975 GRDC gives annual averages and extrema for 1946–1977 • • GRDC summary data disagree with R148 for 1973–1975 rain gauge data suggest that the problem lies with GRDC and there is no reason for rejecting or altering R148 J F M A M J J 139 A S O N D mean mos R148 1973 GRDC 1973 30 - 33 - 6 - 2 33 3 - 25 - 81 - 341 - 378 203 916 935 298 - 122 - 186 179 12 12 R148 1974 GRDC 1974 30 - 13 - 13 46 9 - 11 - 208 - 271 - 794 148 247 209 642 - 797 - 332 - 281 105 12 12 R148 1975 GRDC 1975 192 - 118 22 87 - 83 - 79 - 124 790 89 - 197 - 238 - 244 - 106 - 231 - 149 194 12 5 Asia: Singapore Bukit Timah Canal @ Bukit Timah Rd, km 10 SG AS MY AS • • • • WMO # RIV # River Gauge 9299 9289 106 1291 Bukit Timah Canal Sembrong Bukit Timah Rd, km 10 Brizay Bridge R106 has muddled data from Bukit Timal Canal and the Malaysian gauge Sembrong @ Brizay Bridge WMO gives Bukit Timah Canal correctly the correct discharges are obvious as Bukit Timah Canal discharge magnitudes are substantially lower than Sembrong @ Brizay WMO is retained Asia: Sri Lanka Gin Ganga @ Agaliya LK AS WMO # RIV # River Gauge 9338 1266 Gin Ganga Agaliya • both RIV and WMO have 1927–1986 • • • • • in both RIV and WMO, numerous months are replicated Feb–May are replicated in 1962–1964 Oct–Dec are replicated in 1962–1963 Aug–Sep are identical in 1962 and 1964 Jan 1963–1964 may also be inexact replicates J F M A M J J 140 A S O N D 1962 1963 1964 • • • • 54 61 59 26 26 26 48 48 48 59 59 59 114 114 114 44 61 55 42 94 96 51 101 51 93 116 93 178 179 79 136 136 82 93 93 44 the first instance of the replicated data (1962) was arbitrarily assumed to be correct — this may be wrong Feb–Mar 1963 and 1964 were deleted Oct–Dec 1963 were deleted Aug–Sep 1964 were deleted Kelani Ganga @ Glencourse LK AS • • • • WMO # RIV # River Gauge 9278 1265 Kelani Ganga Glencourse UNESCO sources have 1965–1984 an independent set (IND) has 1949–1984 IND and UNESCO agree on concurrent months the joint IND/UNESCO set is retained Mahaweli Ganga @ Manampitiya LK AS • • • • WMO # RIV # River Gauge 9276 1267 Mahaweli Ganga Manampitiya UNESCO sources have 1965–1984 an independent set (IND) has 1942–1984 with scattered missing months IND and UNESCO agree on concurrent months the joint IND/UNESCO set is retained Mahaweli Ganga @ Peradeniya WMO # LK AS 9337 RIV # 855 River Gauge Mahaweli Ganga Peradeniya • both WMO and RIV span Oct 1949 – Sep 1984 • records agree except for 1976–79 when RIV discharges are higher than WMO • from Jan 1976 – Oct 1978 discrepancies are negligibly small • from Nov 1978 – Dec 1979 discrepancies are significant as shown below 141 • W9337 and R855 may represent data from different gauges not too far apart • it’s not obvious which has the correct data, but RIV has similarly muddled records through the 1970s; hence, chances are better that WMO has the correct record • thus W9337 was kept in the present, but this may be wrong 250 wmo 9337 riv 855 m3/s 200 150 100 50 0 1978 1979 1980 1981 Malwatu Oya @ Kapachchi WMO # LK AS • • • • 9277 RIV # 144 River Gauge Malwatu Oya Kapachchi UNESCO sources have 1965–1975 and 1980–1984 an independent set (IND) has the UNESCO years plus 1946–1964 IND and UNESCO agree on concurrent months the joint IND/UNESCO set is retained Asia: Thailand • • most Thai internal stream gauging is done by the Thai Royal Irrigation Department [RID] (see www.rid.go.th) the Thai Forestry Department, dam operators and maybe others independently operate some gauges 142 • it is unclear which agency operates the Mekong main channel gauges; none are listed in the RID catalogue Thailand: Warning • • one independent source had some mostly older records for several sites these data were added to UNESCO records, but some of the old data appear to have scattered typos Chao Phraya @ Khai Chira Prawat/Nakhon Sawan WMO # TH AS RIV # 9300 888 River Gauge Chao Phraya Khai Chira Prawat/Nakhon Sawan (C.2) Nakhon Sawan • • WMO and RIV had 1976–1984 an independent record obtained via the Thai Royal Irrigation Department [RID] ca. 1990, had 1956–1989 • • • UNESCO files call this gauge Nakhon Sawan Khai Chira Prawat is the gauge name and C.2 is the gauge code used by RID the gauge is in or near Nakhon Sawan city Chi @ Yasothon WMO # TH AS 9339 RIV # 889 River Gauge Chi Yasothon • • • WMO and RIV had 1953–1987 an independent source (IND) had 1951–1985 the early data from IND not in UNESCO are pre-pended • the old data for 1951 are extremely high and may be in error Mekong River – Warning: Mis-scaled data TH AS TH AS TH AS WMO # RIV # River Gauge 9340 9342 9343 1248 891 1461 Mekong Mekong Mekong Mukdahan Chiang Saen Nakhon Phanom 143 • records for the 3 Thai Mekong gauges in WMO must be multiplied by 10 to bring them to the correct scale • in RIV, only R1461, Nakhon Phanom needs to be scaled up by 10-fold Mekong @ Chiang Saen WMO # TH AS 9342 RIV # 891 River Gauge Mekong Chiang Saen • • WMO and RIV span May 1960 – Apr 1987 an independent set (IND) has daily discharges for 1980–1987 with scattered missing months • from 1976–79, RIV has numerous discrepancies with WMO; the four largest are listed below; the two largest are almost surely typos in RIV 1976 1977 1978 1979 • • 2 2 8 5 WMO RIV dif %dif seasonal 963 893 6,870 1,100 929 925 3,870 110 34 -32 3000 990 3.6 3.5 55.9 163.6 934 934 6,602 1,210 WMO was retained data for May–Dec 1987 were added from IND Mekong @ Mukdahan TH AS • WMO # RIV # River Gauge 9340 1248 Mekong Mukdahan available data sets are listed below: data set 1st yr last yr net yrs IHD RIV IND1 1924 1924 1923 1971 1987 1987 47.8 63.2 64.2 WMO GRDC 1947 1924 1987 1991 40.0 66.3 IND2 1980 1989 6.0 144 • there are two main series that differ only from Jun 1947 – Dec 1970 1. IHD / R1248 / IND1 are identical on concurrent months except for a few errata and that IND1 has a record for 1923 the seems typical for the site 2. W9340 / GRDC summary data are identical for concurrent months, but differ somewhat from IHD / R1248 through the 1950s and early 1960s • IND3 is a collection of daily record fragments for the 1980s that includes some data for 1987 and 1989 not in the others A. 1923–1946 • • IHD, RIV and IND1 are nearly identical except for a few typos that may be errors in RIV, but are small enough to have little effect IHD was retained for this period 1926 2 1937 6 1942 9 • RIV IHD/IND1 dif %dif seasonal 1,992 7,077 18,274 1,922 7,007 18,724 70 70 -450 3.6 1.0 2.4 1,865 7,050 21,154 beware — the 1923 Jun discharge given by IND1 (15,300 m3/s) would be the highest on record if it were valid; Jun discharge has gone to 12,000–13,000 so 15,000 is plausible; but this could just as easily be a transcription error, e.g. the true discharge might be 5,300 B. 1947–1970 • • RIV / IHD are identical except for a few typos WMO / GRDC are identical • there are perceptible differences between RIV/IHD and WMO/GRDC • • • WMO and RIV disagree on 260 of 283 common months 200 of the discrepancies are minor rounding jitter about 45 are larger, but still small (1–10% absolute) differences that may be due to having slightly different versions of the series, and some may be minor typos of the remaining 15 perceptible differences, 14 occur from 1947–52, 10 of which occur in sequence from Mar 1950 – Jan 1951 (see below) • WMO RIV dif %dif 145 seasonal 1950 2 1950 3 1950 4 1950 5 1950 6 1950 7 1950 8 1950 9 1950 10 1950 11 1950 12 1951 1 1951 2 2,270 1,860 1,670 2,630 8,290 17,240 24,690 18,710 14,940 7,590 3,510 2,400 2,110 2,230 1,655 1,461 2,142 5,551 14,020 20,896 20,838 16,068 9,089 4,449 2,669 2,133 40 205 209 488 2,739 3,220 3,794 -2,128 -1,128 -1,499 -939 -269 -23 1.8 11.7 13.4 20.5 39.6 20.6 16.6 10.8 7.3 18.0 23.6 10.6 1.1 1,869 1,556 1,496 2,287 7,098 14,181 21,927 21,156 12,003 5,961 3,581 2,401 1,869 1965 10 8,750 2,757 5,993 104.2 12,003 • as RIV data are identical to the IHD data submitted 25 years ago, and the WMO data seem to represent a more recent retrieval that may have retrospective revisions made since 1972, WMO was accepted as the base record for 1947– 1970 in the merged data set C. Jan 1971 – May 1987 • all sources are identical on this segment except for two discrepancies below that appear to be typos in RIV 1972 1974 3 6 WMO / IND1 RIV dif %dif seasonal 972 5,900 9,720 5,090 -8,748 810 163.6 14.7 1,556 7,098 D. Independent set IND2 1980 – 1989 • • • • independently obtained set IND2 is a collection of daily discharge record fragments for the 1980s that includes some data for 1987 and 1989 not in the others there is nearly 1:1 correspondence between IND2 and the others, but there are scattered deviations that do not show a consistent pattern some fragments of IND2 may have been provisional data releases since revised in the official record consequently, Jun-Dec 1987 and Jan-Dec 1989 fragments were simply added to the end of the composite IHD/WMO record for Apr 1924 – May 1987 with the caveat that these are likely provisional data that may have been revised in the official release 146 30,000 25,000 20,000 15,000 10,000 5,000 0 1980 1981 1982 1983 1984 1985 RIV 1986 1987 1988 1989 IND2 Mun @ Ubon Ratchathani WMO # TH AS • • • 9341 RIV # 890 River Gauge Mun Ubon Ratchathani • WMO and RIV have 1955–1987 an independent source (IND) gives 1944–1954 1952–1953 look typical, but 1944–1951 have some exceedingly high entries that are impossible to corroborate definitively at present rain gauge data suggest that the pre-1952 IND discharges may not be too reliable • the joint IND / UNESCO set is retained for 1952–1987 • • pre-1952 data from IND are listed below for anyone who wants to muck about rain gauges indicate that several of these years were completely dry in Nov–Dec 9341 9341 9341 9341 9341 9341 9341 9341 1944 1945 1946 1947 1948 1949 1950 1951 J F M A M J J A S O N D 200 30 17 18 253 78 178 988 540 183 343 332 1200 745 947 300 249 612 1110 633 1010 1360 933 503 494 2020 2130 2130 1630 2650 2350 2250 2350 2040 2360 2280 2060 2190 2860 3110 4210 2140 1710 1020 1490 915 1200 3140 236 693 438 595 353 291 1160 1240 1040 147 Tapi @ Surat Thani TH AS • • • WMO # RIV # River Gauge 9348 1359 Tapi Surat Thani WMO and RIV have 1980–1984 an independent source (IND) gives 1969–1979 the joint set is retained — beware of potential typos in 1969–1979 Trang @ Trang TH AS • • • • • WMO # RIV # River Gauge 9349 1360 Trang Trang WMO and RIV have 1980–1984 an independent source (IND) gives 1966–1979 the joint set is retained beware of potential typos in 1969–1979 the high Jan 1967 and 1975 discharges are consistent with abnormally high Jan rainfall in those years Asia: Thailand / Laos Mekong @ Nakhon Phanom / Thakhek TH AS WMO # RIV # River Gauge 9343 1461 Mekong Nakhon Phanom • as noted elsewhere, both WMO and RIV data at this site were 10-fold too low in the respective source files • WMO and RIV span 1962–1987 and are generally identical • an independent source gives 1936–1965 excluding Jan 1945 – Aug 1947 for a Laotian gauge called Thakhek which is the town on the opposite bank of the river to Nakhon Phanom 36 concurrent months from 1962–1965 of Thakhek and Nakhon Phanom records are identical within rounding limits • • 1989 Nakhon Phanom data were added from an independently obtained set of daily discharges 148 8.0 Middle East Middle East: Cyprus Limnitis @ Limnitis Saw Mill CY AM • • WMO # RIV # River 9873 Limnitis Limnitis Saw Mill 115 Gauge the 1973 record fragment from R115 shown below is not in W9873 for Jan–Apr 1973 discharges are well below the minima for 20 years of gauge record in W9873 this fragment was deleted • J 1973 median min F M A M J J A S O N D 0.050 0.080 0.070 0.040 0.010 0.000 0.000 0.000 0.000 -00 -00 -00 0.775 1.070 1.045 0.506 0.254 0.106 0.042 0.014 0.014 0.033 0.077 0.234 0.134 0.188 0.168 0.085 0.058 0.012 0.000 0.000 0.000 0.005 0.032 0.101 Middle East: Iraq Tigris and Euphrates WMO # RIV # River Gauge 9212 9213 9214 9215 812 813 811 1243 Tigris (Dijlah) Tigris (Dijlah) Euphrates (Al-Firat) Euphrates (Al-Firat) Mosul Baghdad Hit Hindiya IQ IQ IQ IQ AM AM AM AM • • UNESCO sources give data for Oct 1964 – Dec 1972 RIV data for 1968–1972 are still on local water years • • an independent source had older records for these sites for W9212, W9213 and W9215, IND had data from 1906–1923 up to 1932–1933, as well as the same Oct 1964 – Dec 1972 data in UNESCO files • • for W9214 (Euphrates @ Hit), IND had 1924–1932, 1937–1952 and 1964–1972 in 1964, IND had Jan–Sep not available in UNESCO files • • the joint IND/UNESCO data were retained WARNING: IND data not concurrent with UNESCO files could presently not be corroborated 149 Middle East: Israel Jordan @ Southern Stn / Jordan @ Obstacle Bridge WMO # River Gauge Area Jordan Jordan Southern Stn Obstacle Bridge 1,495 1,376 IL IL AM AM • RIV compilers merged the records of these two gauges into a single record identified with the most upstream site WMO gave these separately in the present set, they are given as the original two distinct gauges • W9863 with 1966–1972 • W9864 with 1976–1984 • • 9863 9864 RIV # 795 Middle East: Jordan Zerqa @ Jerash Bridge / Yarmouk @ Maqarin JO AM JO AM WMO # RIV # River Gauge 9867 9868 1275 123 Zerqa Yarmouk Jerash Bridge Maqarin • • for 1965, 1967 and 1968, R1275 Zerqa data are identical to Yarmouk W9868 / IHD R123 Yarmouk has no data for these years • WMO appears to have the correct data at each site (with the exception of a typo discussed below) J F M A M J J A S O N D R1275 1965 1966 1967 1968 22.0 0.6 13.0 - 21.0 0.6 26.0 - 8.3 7.4 42.0 3.4 7.2 1.1 12.0 - 6.0 86.0 7.3 3.2 5.6 0.8 7.9 3.8 6.0 0.6 8.5 3.5 5.9 0.6 9.5 4.0 6.0 0.7 9.8 4.5 6.3 2.9 6.2 6.1 3.5 6.7 6.6 4.2 25.0 WMO 9868 1965 1966 1967 1968 22.0 6.4 13.0 - 21.0 7.4 26.0 - 8.3 9.0 42.0 3.4 7.2 5.8 12.0 - 6.0 4.5 7.3 3.2 5.6 4.6 7.9 3.8 6.0 4.6 8.5 3.5 5.9 4.8 9.5 4.0 6.0 5.7 9.8 4.5 6.3 7.6 2.9 6.2 6.1 7.3 3.5 6.7 6.6 16.0 4.2 25.0 150 • • • W9868 / R123 Yarmouk @ Maqarin, both have the typos shown below the area receives no precipitation during these months, and none was observed during 1971 at several Jordan rain gauges in the area in both cases, the correct discharge would seem to be 4.4 not 40.4 RIV WMO 1971 1971 J F M A M J J A S O N D 7.4 7.4 9.7 9.7 11.5 11.5 44.2 44.2 6.8 6.8 4.6 4.6 4.4 40.4 40.4 4.4 4.5 4.5 4.5 4.5 4.5 4.5 5.0 5.0 Middle East: Syria Euphrates @ Kadaheyah / Yusuf Basha SY AM SY AM WMO # RIV # River Gauge 9859 Euphrates Euphrates Kadaheyeh Qushlat Yusuf Basha (Youssef Pacha) 800 Lat Lon 36.53 38.25 36.36 38.18 El Area 307 114,000 294 97,000 • WMO and RIV give the same data for the two distinct locations above • if the coordinates are correct, the two sites are ca. 15 km apart • the coordinates and elevation place Kadaheyeh upstream of Yusuf Basha, but by drainage area, Yusuf Basha should be upstream of Kadaheyeh • Yusuf Basha was found in two gazetteers, but Kadaheyeh cannot be found in any available gazetteers and maps which is not a definitive indication that the place does not exist 9.0 Australia General Remarks • • stream gauging in Australia is the responsibility of the states and territories presently, up-to-date data are available on-line for three Western Australian gauges in UNESCO files at www.wrc.wa.gov.au/waterinf/wric/SearchByCriteria.asp WMO # AU AU AU AU AU AU • • 9719 9717 9718 RIV # 426 427 951 River Gauge Fitzroy Ord Ord Dimond Gorge Coolibah Pocket Ord R Homestead UNESCO records for these three were simply replaced by the current versions the other states and territories do not yet appear to have on-line data dissemination 151 • data for the other seven Australian sites should be replaced with current versions when the opportunity arises • • • nominally, the UNESCO files have records for 10 gauges four of these represent two pairs of gauges each pair involves an older gauge that has since been discontinued and a newer gauge that remains operational in both cases, the pairs of gauges were operated concurrently for 9–15 years • WMO # RIV # River Gauge Lat Lon Area AU AU AU AU 9714 9715 424 Daly Daly Gourley Mount Nancar -13.90 130.80 -13.83 130.73 46,300 46,600 AU AU AU AU 9720 9721 421 Fitzroy Fitzroy Yaamba The Gap -23.15 150.37 -23.10 150.10 136,650 135,860 • • • • • • these records can be composited into two operational records; however, the original records should be maintained separately to avoid confusion when comparing records with original source data RIV compilers composited the available records for each pair into single records without clearing indicating that this had been done several of the 10 gauges in UNESCO files drain arid terrain that experiences sporadic high discharges comparisons of the multiple versions of records available for the three Western Australian gauges show that the historical records have been revised numerous times for these and similar streams, the stage-discharge curves, particularly for rarely occurring high flows, are likely “works in progress” that are revised when new metering data become available of the UNESCO records, similar conditions likely pertain for the three Northern Territory gauges (below) AU AU AU AU AU AU WMO # RIV # River Gauge 9714 9715 9716 424 1114 Daly Daly Victoria Gourley Mount Nancar Coolibah Homestead Burdekin @ Clare WMO # AU AU 9722 RIV # 423 River Gauge Burdekin Clare 152 • • • IHD, WMO, RIV and two independent sources have data for 1965–1968 and 1973– 1984 IHD and one independent source give the 1965–1968 data in cfs (ft3/s) a record obtained from the Australian Bureau of Meteorology has 1950–1998 • • • • Sep 1965 is a probable typo in WMO and RIV in the original imperial units given in IHD, Sep 1965 had 8 cfs = 0.227 m3/s WMO and RIV give Sep 1965 as 235 m3/s = 8,299 cfs the original data for 1965–1968 have been retained after conversion to metric • the new Australian record replaces the UNESCO data Daly @ Gourley / Mount Nancar WMO # AU AU AU AU 9714 9715 RIV # 424 River Gauge Daly Daly Gourley Mount Nancar Lat Lon Area -13.90 130.80 -13.83 130.73 46,300 46,600 • • • IHD, WMO and an independent source give these records separately Gourley has Jan 1965 – Aug 1974 Mount Nancar has 1976–1984 with some missing months • • in RIV, the two records are composited in R424 under the label Mount Nancar the sites are close enough to permit this for most operational purposes • for the present set, the two distinct records are retained as originally given Fitzroy @ Yaamba / The Gap WMO # AU AU AU AU 9720 9721 RIV # 421 River Gauge Fitzroy Fitzroy Yaamba The Gap Lat Lon Area -23.15 150.37 -23.10 150.10 136,650 135,860 • • • • IHD and WMO give these records separately Yaamba has Jan 1965 – Dec 1968 IHD gives Yaamba in cfs not m3/s The Gap has 1973–1984 • in RIV, the two records are composited in R421 under the label The Gap 153 • the sites are close enough to permit this for most operational purposes [though the given coordinates seem to place these gauges too far apart] • for the present set, the two distinct records are retained as originally given Victoria @ Coolibah Homestead AU AU WMO # RIV # River Gauge 9716 1114 Victoria Coolibah Homestead • WMO, RIV and an independent source generally give the same data except that RIV is missing 1980 and gives a discharge for Dec 1971 when the others have no data for 1971 • • • the Dec 1971 discharge given by RIV is 49 all sources give 1977 as missing all months except Dec which has discharge 49 hence, the Dec 1971 entry in RIV is suspicious and has not been retained • an Australian stream gauge inventory rates data for this site as being of poor quality 10.0 Pacific Ocean Pacific Ocean: New Zealand Buller @ Te Kuha WMO # NZ PO 9732 RIV # 433 River Gauge Buller Te Kuha • • WMO and RIV give nearly the same data for 1976–1984 RIV also has 1964 • there are 2 minor discrepancies that cannot be resolved without source data • • in Mar 1980, W9732 has 367 while R433 has 376 in Jun 1982, W9732 has 385 while R433 has 375 • R433 was retained 154 Cleddau @ Milford WMO # NZ PO • • RIV # 9728 429 River Gauge Cleddau Milford WMO and RIV give the same data for 1969–1975 RIV also has 1965 Clutha @ Balclutha WMO # NZ PO RIV # 9729 425 River Gauge Clutha Balclutha • • • WMO and RIV give the same data for 1969–1984 an independent set (IND) has 1954–1984 with 1968 and Jan–Jul 1954 missing on current years all sets agree • IND is retained Clutha @ Clyde WMO # NZ PO RIV # 9735 430 River Gauge Clutha Clyde • • WMO and RIV give nearly the same data for 1980–1984 RIV also has 1964 • • • for Nov 1982, W9735 discharge = 7663 is an error RIV gives 763 the downstream gauge at Balclutha with almost twice the drainage area has 828 • RIV is retained Hutt @ Kaitoke WMO # NZ PO • • 9923 RIV # 437 River Gauge Hutt Kaitoke UNESCO has only 1965 PACRIM has complete 1968–1994 data 155 • the PACRIM record is retained with UNESCO 1965 pre-pended Omakere @ Fordale WMO # NZ PO • • • • 9734 RIV # 439 River Gauge Omakere Fordale WMO and RIV give nearly the same data for 1980–1984 RIV also has 1965 R439 is shifted 1 month ahead of W9734 during 1982 R439 was retained for the time being, but this may be wrong R439 W9734 1982 1982 1982 1982 1982 1982 1982 1982 1982 1982 1982 1 2 3 5 6 7 8 9 10 11 12 -9.00 0.00 0.00 -9.00 0.61 3.90 2.10 0.47 0.20 0.12 0.55 0.00 0.00 -9.00 0.61 3.90 2.10 0.47 0.20 0.12 0.55 0.00 Selwyn @ Whitecliffs WMO # NZ PO • • • • 9920 RIV # 434 River Gauge Selwyn Whitecliffs RIV has 6 years of data [1965, 1980–1984] PACRIM has complete 1965–1994 data on concurrent months there are minor discrepancies on the order of rounding jitter except for a few months in 1965 the more recent PACRIM record is retained Waikato @ Lake Taupo Outlet WMO # NZ PO • 9727 RIV # 438 River Gauge Waikato Lake Taupo Outlet Lat Lon Area -38.70 176.07 3,290 3,430 this site is also referred to as “Lake Taupo Control” or “Lake Taupo Gate” in some sources 156 • • • UNESCO sources give 1966 and 1969–1975 an independent source (IND) gives 1905–1967 on the one concurrent year (1966), IND and UNESCO agree • • • the drainage area is uncertain IND gave the higher drainage area of 3,430 km2 there is some chance that IND may be a different gauge for some or all of the period • the joint IND / UNESCO data set is retained Wanganui @ Paetawa NZ PO WMO # RIV # River Gauge 9730 1383 Wanganui Paetawa • • WMO and RIV give 1976–1984 an independent source (IND) gives 1950–1990 with 1967 missing • except for two errors in RIV, all sources agree on concurrent years • • • for Jan 1980, R1383 discharge = 33 is likely an error the other sources give 333 Jan discharges of 33 and 333 respectively would be the lowest and highest on record the Hutt @ Kaitoke data confirm that for southern parts of the North Island, Jan 1980 was abnormally wet • • • for Jun 1984, R1383 discharge = 1,383 is an error the other sources give 138 • IND is retained Pacific Ocean: Papua New Guinea Purari @ Wabo Dam site WMO # PG PO 9733 RIV # 662 River Gauge Purari Wabo Dam site Area 28,749 • • WMO and RIV identically have 49 months of scattered data from 1976–1984 an independent source gives 25 scattered months from Dec 1961 – Dec 1964 • some sources still give the drainage area in square miles (11,100) as if km2 157 • the joint set of 74 months of data is retained Tauri @ Hells Gate WMO # PG PO 9737 RIV # River Gauge 685 Tauri Hells Gate • • WMO and RIV identically have 32 months from 1981–1984 an independent source gives 56 scattered months from Oct 1952 – Sep 1961 • the joint set of 88 months of data is retained 11.0 Europe Europe: Albania Albanian Gauges Updated from MED-HYCOS AL AL AL AL AL EU EU EU EU EU AL EU WMO # RIV # River Gauge 9745 9747 9749 9750 9751 Devolli Mati Erzeni Drin i Zi Osumi Kokel Shoshaj Ndroq (Ndreq) Ura e Dodes (Skavice) Ura Vajgurere Shkumbini [Medhycos] Papër 766 1236 758 767 1238 10125 • • • the records above were updated from MED-HYCOS UNESCO files have 1976–1984 MED-HYCOS has roughly 1950 to early 1990s • Shkumbini @ Papër is a problem record discussed in its own subsection below Drin @ Kalimash / Vau i Dejes WMO # AL EU AL EU 9746 9748 RIV # 208 River Gauge Drin Drin Kalimash Vau i Dejes 158 Lat Lon Area 42.08 20.31 42.01 19.62 -9 12,368 • • • Vau i Dejes is not too far upstream from the Adriatic Sea at the lower end of a large reservoir (Laq i te Dejes) if coordinates are correct, Kalimash is appreciably further upstream below the confluence of the Beli Drin and Drin i Zi near Kukes there is an appreciable difference in drainage area between the two • WMO gives these apparently correctly as two distinct records Drin @ Vau i Dejes for 1965–1968 and Drin @ Kalimash for 1969–1975 • IHD had given the composited record for 1965–1972 as Drin @ Vau i Dejes • RIV gave the composited record as Drin @ Kalimash with elevation and drainage area for Drin @ Vau i Dejes • and independent source gives the Drin @ Vau i Dejes as in WMO, but Drin @ Kalimash as in RIV • 1965–1968 Drin @ Vau i Dejes data yield mean annual discharge nearly twofold higher than that of 1969–1975 Drin @ Kalimash data this suggests that Vau i Dejes is the correct location for the 1965–1968 data, but as there is no temporal overlap, it is not definitively clear that 1965–1968 data do not belong to Kalimash • • • • • a further problem with the Drin @ Vau i Dejes is the presence of two probable typos in all versions except W9748 specifically, Jul 1965 and Aug 1968 are given as 13 while WMO gives 130 evidence is limited by short records, but there is nothing to suggest that such low discharges occur normally, if at all, at Vau i Dejes which lies below a system of large reservoirs for the present data set, the two distinct records as given by WMO are retained Shkumbini @ Papër AL EU AL EU • • • WMO # RIV # River Gauge 9752 10125 Shkumbini Shkumbini [Medhycos] Papër Papër 1237 runoff mm 952 559 UNESCO record W9752/R1237 has 1976–1984 MED-HYCOS gives 1950–1990 for nominally the same gauge; however, MEDHYCOS data are 58% lower for the concurrent 1976–1984 period the two records appear to represent different gauges in the same river system, but which gauge belongs to Papër is unclear 159 • • • both records yield plausible mean annual specific runoff for available Albanian gauges, specific runoff varies from 480–1,200 mm differences seem to be mainly attributable to the extent of lowland terrain within the upstream watershed as higher elevations receive perceptibly more rainfall • it is unlikely that the confusion can be resolved without direct recourse to Albanian authorities the MED-HYCOS record is retained under ID # 10125 • Europe: Bulgaria Two sites with additional data from independent sources WMO # BG EU BG EU • • • • • • 9758 9762 RIV # 775 181 River Gauge Kamchiya Maritza Gzozdevo Plovdiv UNESCO sources have 1965–1979 for these two an independent source (IND) gives 1935–1986 and 1936–1985 respectively MED-HYCOS gives 1968–1997 for Maritza @ Plovdiv IND and UNESCO sources agree within rounding limits on concurrent months joint IND/UNESCO data were retained for Kamchiya @ Gzozdevo joint IND/MED-HYCOS data were retained for Maritza @ Plovdiv Maritza @ Kharmanli (Harmanli) WMO # BG EU BG EU • • • • 9757 9762 RIV # 774 181 River Gauge Maritza Maritza Kharmanli (Harmanli) Plovdiv Area 19,693 7,981 the 1966 data for Maritza @ Kharmanli are from another gauge with much lower discharge other Bulgarian data suggest that 1966 should have slightly lower mean level than 1965 and 1967, i.e., the same pattern as observed at the upstream gauge at Plovdiv the same erroneous data are present in all versions of this record including GRDC summary data 1966 was deleted 160 200 Maritza River, mean annual discharge series 180 160 140 cms 120 100 80 60 40 20 19 36 19 38 19 40 19 42 19 44 19 46 19 48 19 50 19 52 19 54 19 56 19 58 19 60 19 62 19 64 19 66 19 68 19 70 19 72 19 74 19 76 19 78 19 80 19 82 19 84 0 Plovdiv Harmanali Struma @ Razdavitza / Krupnik WMO # BG EU BG EU • • 9760 9761 RIV # 773 771 River Gauge Area Struma Struma Razdavitza Krupnik 2,171 6,780 the gauge names for these two were reversed in WMO, RIV and GRDC other metadata (coordinates, drainage area, elevation) appear to be correct after exchanging the gauge names as shown above Europe: Czech Republic Elbe (Labe) @ Decin CZ EU WMO # RIV # River Gauge 9765 1240 Elbe (Labe) Decin • • the UNESCO files have 1851–1984 an independent version (IND) gives 1851–1990 • • UNESCO files have one typo Jul 1954 should be 138 not 738 • IND is retained 161 Europe: Finland Kemi @ Taivalkoski WMO # RIV # River Gauge 781 Kemi Kemi Taivalkoski Isohaara FI EU • • the UNESCO files have a record Kemi @ Taivalkoski for 1911–1984 some sources refer to a gauge designated Kemi @ Isohaara with record dating from 1941 these may be the same entity • 9780 Area 50,790 50,683 Kymi @ Pernoo WMO # RIV # River Gauge 782 Kymi Kymi Pernoo Anjala FI EU • the UNESCO files have a record Kymi @ Pernoo for 1900–1984 that is widely available in other sources some references refer to a gauge identified Kymi @ Anjala with slightly smaller drainage area (variably given as 36,275–36,305 km2) and a record beginning in 1938 • 9779 Area 36,535 36,305 • a recent GRDC summary gives the annual series for a gauge that is nominally Kymi @ Anjala with annual discharges that are persistently lower by from 0–10% than the UNESCO series for Kymi @ Pernoo on concurrent years • so be warned: there may be two distinct records circulating for two distinct gauges that are in close proximity this may also be a case of the same gauge under different labels with different revisions of the historical record • Vuoksi @ Imatra WMO # 783 River Gauge Vuoksi Tainionkoski (Imatra) FI EU • 1850 of W9781 is replicated in 1851 and records are shifted forward 1 year through 1856 R783 appears to have the correct chronology • 9781 RIV # 162 Europe: France Garonne @ Mas-d'Agenais WMO # FR EU 9803 RIV # 736 River Gauge Garonne Mas-d'Agenais • all versions have 1920–1979 • • • • for Sep 1941: U72 / R736 give 238 WMO / GRDC give 138 although somewhat removed, Loire & Rhone discharges suggest that WMO/GRDC have the correct discharge WMO is retained • Rhone @ Beaucaire — Warning: potential drainage area decrease due to diversion WMO # FR EU 9802 RIV # 740 River Gauge Rhone Beaucaire Area Effective Area 95,590 81,360 • • • the UNESCO series give 1920–1979 numerous versions of the record exist that include more recent data these are essentially all the same • the UNESCO series and GRDC summary data all have one notable typo — Apr 1970 should be 3,080 (mean of daily discharges) not 2,080 • for the present set, the UNESCO records were updated from 1920–1999 with monthly means derived from daily discharge data from MED-HYCOS Warning: in early 2000, the monthly series available at MED-HYCOS was riddled with errors; use monthly means derived from the daily discharges • Potential Drainage Area / Discharge Reduction • • according to site metadata at MED-HYCOS, some time in the past, the effective drainage area of this gauge was substantially reduced by diversion of the Durance tributary per the plot below, there is no obvious evidence of perceptible reduction in mean discharge level that might be expected if drainage area had been reduced by 16% 163 • interested parties might contact the responsible agency for clarification [Compagnie Nationale du Rhône (CNR); 2, rue André Bonin, 69316 LYON CEDEX 04] • • all UNESCO sources including GRDC give the larger former drainage area for the time being, specific runoff estimates should be treated with due caution 2500 cms 2000 1500 1000 Rhone @ Beaucaire: Mean Annual discharge 1920-1999 500 1920 1925 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 Rhone @ La Mulatiere / Givors WMO # FR EU FR EU RIV # 9800 9801 741 River Gauge Rhone Rhone La Mulatiere Givors Lat Lon El Area 45.75 45.73 4.84 4.83 154 148 50,200 51,080 • • • La Mulatiere has a record from 1900–1972 Givors spans 1973–1984 Givors has apparently superseded La Mulatiere • • WMO gives these two separately R741 is a composite of the La Mulatiere and Givors • in the present set, the two records are given distinctly as in WMO Europe: Germany Elbe @ Darchau WMO # DE EU 9788 RIV # River Gauge Elbe Darchau 164 • • data in this record have been variably labelled Darchau and Neu-Darchau with slightly different coordinates the record may be a composite of two distinct gauge records, but if the gauge was moved, the two locations would not be far apart • • • WMO and IHD have 1969–1975 two independent sources (IND1 and IND2) also give 1978–1980 and 1984–1988 on concurrent months IND1 agrees with the UNESCO files, and IND2 agrees with IND1 • the joint UNESCO/IND set is retained Elbe @ Wittenberge WMO # DE EU RIV # 9789 759 River Gauge Elbe Wittenberge • • • WMO gives 1976–1984 RIV gives 1969–1984 an independent source (IND) gives 1920–1989 • on concurrent months from 1969–1975, RIV and IND disagree on nearly all months; some discrepancies approach 25% on concurrent months from 1976–1984, RIV, WMO and IND are in nearly perfect agreement differing by only minor rounding jitter there is reason to suspect that the 1969–1975 data given by RIV may be old or preliminary release data • • • the joint WMO/IND set is retained Europe: Greece Aliakmon @ Il Arion WMO # GR EU RIV # 9852 River Gauge Aliakmon Il Arion • • • among UNESCO files, this is only available in WMO which gave 1976–1979 an independent source (IND) gives 1962–1988 IND seems to be the same series found at MED-HYCOS and also GRDC • IND is retained 165 • the first 8–9 months in late 1962 – early 1963 are exceptionally high and may be in error Europe: Hungary Danube @ Nagymaros area km2 WMO # RIV # River Gauge HU EU 9869 757 Danube Nagymaros 183,000 YU EU 9739 756 Danube Bezdan (Serbia) 210,245 • W9869 and R757 agree perfectly except over 1975 and 1976 • the downstream gauge at Bezdan (where WMO and RIV agree perfectly) was used for comparison • in 1975, R757 appears to have an erroneous value (5,088) inserted in Aug, forcing the Aug value ahead 1 month before the series returns to sync in Oct 1975 1975 1975 1975 1975 • • • 7 8 9 10 WMO Bezdan R756 5,040 5,088 2,590 1,450 5,040 2,591 2,201 1,453 4,870 2,600 2,480 1,470 in 1976, W9869 and R757 disagree over the entire year there’s no clear choice as to which is the better record — either one or the other has been revised, or represents another Danube gauge in Hungary or Serbia (there are several) two independent versions are identical to W9869 1976 1 1976 2 1976 3 1976 4 1976 5 1976 6 1976 7 1976 8 1976 9 1976 10 1976 11 1976 12 • Nagymoros RIV R757 W9869 dif %dif R756 2,588 1,700 1,486 1,874 2,052 2,482 1,394 1,779 1,752 1,413 1,447 2,081 2,537 1,602 1,366 1,619 1,983 2,514 1,500 1,852 1,818 1,359 1,338 1,584 -51 -98 -120 -255 -69 32 106 73 66 -54 -109 -497 -2 -6 -8 -15 -3 1 7 4 4 -4 -8 -27 2,610 1,890 1,520 1,760 1,900 2,470 1,180 1,720 1,660 1,370 1,380 2,150 W9869 was retained 166 Tisza @ Polgar / Tiszapalkonya HU EU HU EU • • • WMO # RIV # River Gauge Area 9753 9754 770 1276 Tisza Tisza Polgar Tiszapalkonya 62,723 62,725 Lat Lon 47.90 21.07 47.88 21.06 in 1980, the gauge at Polgar appears to have been closed and moved to Tiszapalkonya Polgar is the main town and Tiszapalkonya seems to be an outlying neighbourhood or district if available information is correct, Tiszapalkonya is slightly downstream of the older gauge, i.e., has a slightly higher drainage area and is slightly south — this is contrary to various sources which give Tiszapalkonya a higher drainage area and place it north (upstream) of the Polgar gauge • these two records originate from such close locations that they can be composited without adjustment • • • • • W9754 and R1276 disagree on Dec 1984 W9754 gives 315 R1276 gives 375 it is unclear which is correct W9754 is retained Europe: Iceland General Remarks WMO # 188 189 187 190 River Gauge Thjorsa Joekulsa a Fjollum Olfusa Lagarfljot Urridafoss Dettifoss (Ferjubakki ?) Selfoss Lagarfoss IS IS IS IS EU EU EU EU • three of the four gauges in UNESCO files had longer records available in the Arctic drainage data set at R-Arcticnet for two of these there are only minor differences between the longer records and the UNESCO records on concurrent months • 9772 9773 9774 9775 RIV # 167 • • • • • for the third record, Olfusa @ Selfoss, there are ubiquitous differences on concurrent months that appear to represent significant retrospective revision of the record for some months, high discharges particularly, differences exceed 10% at the fourth site, Lagarfljot @ Lagarfoss, the GRDC summary of a longer, more recent record suggests that the Lagarfljot @ Lagarfoss record has seen significant revision the May 1972 entry in UNESCO sources (36.2 m3/s) may be a typo; the GRDC annual summary claims that the maximum monthly discharge for 1972 was 372 and occurred in May; hence, the UNESCO discharge perhaps should have been 362 for the present, the UNESCO record is retained Europe: Ireland Shannon @ Killaloe WMO # RIV # River Gauge 9821 1002 Shannon Killaloe IE EU • • • UNESCO sources give 1973–1979 an independent source (IND) gives 1935–1979 IND and UNESCO agree on concurrent months • the joint IND/UNESCO set is retained with the caution that the 1934-1972 data could not be corroborated Europe: Italy Po @ Boretto WMO # 9847 RIV # 750 River Gauge Po Boretto IT EU • • • • UNESCO sources have 1965–1979 an independent source (IND) gives 1951–1960 and 1965–1979 IND and UNESCO are identical on concurrent months the joint IND/UNESCO set is retained 168 Po @ Pontelagoscuro WMO # 751 River Gauge Po Pontelagoscuro IT EU • • 1. 2. 3. the UNESCO series give 1918–1979 independent sources give: monthly discharges (IND1) from 1970–1995 daily discharges for 1995–1998 from MED-HYCOS the data series retained is a composite of UNESCO / IND1 / MED-HYCOS • • IND1 agrees with UNESCO over 1970–1979 1980–1994 taken from IND1 cannot be corroborated at present and have a few suspiciously high data the MED-HYCOS are consistent with earlier data and seem accurate • 9848 RIV # Tiber (Tevere) @ Ripetta (Roma) WMO # Gauge Tiber (Tevere) Ripetta (Roma) EU • • 1. 2. 3. WMO, RIV and IHD have essentially the same data spanning 1921–1979 several independent data sets were found including: daily discharges (IND1) for 1921–1985 with 1984 missing monthly discharges (IND2) for 1921–1995 from MED-HYCOS daily discharges (IND3) for the late 1990s at MED-HYCOS • for 1921–1950, monthly means from IND1 agree with the UNESCO data sets except for minor rounding jitter and a few typos from Dec 1950 through Dec 1979, there are persistent discrepancies between the UNESCO sets and IND1 and IND2 the MED-HYCOS monthly data (IND2) are similar to IND1, but have a few discrepancies that are likely data entry errors • 202 River IT • 9851 RIV # 169 750 650 550 450 350 250 150 50 1969 1970 1971 1972 1973 1974 IND • • • 1975 1976 1977 1978 1979 R202 1984 and 1986–1994 taken from IND2 (MED-HYCOS monthly series) may contain some data entry errors the late 1990 daily discharges are consistent with earlier data and seem reliable the data set retained here is a composite of monthly means derived from the independent sources IND1, IND2 and IND3 Europe: Norway Glomma @ Langnes (Solbergfoss) WMO # NO EU • • • 9771 RIV # 760 River Gauge Glomma Langnes (Solbergfoss) this record is variably identified as being located at Langnes or Solbergfoss the two places are near each other the Glåma River is variably identified in English sources as Gloma, Glomma, Glama, Glommen, and likely other variants — Glomma seems to be the most widely used English transliteration 170 Europe: Portugal General Remarks • • Portuguese discharge data are available on-line at snirh.inag.pt/snirh/ [click “Dados de Base”] INAG is a research institute, not the national data collection service; hence, data may not be the most current and may have errata introduced during data transfer • most of the 16 gauges with records in the UNESCO files may now be out of service • • • the site below is a dam upstream on the Douro on the INAG site, discharge records for dams are maintained separately no records for Pocinho were available in early 2000 PT EU • • • • WMO # RIV # River Gauge 9826 1277 Douro Pocinho at the other 15 gauges, monthly and daily discharge records are available at 13 of 15; while two have only daily records for the 13 with monthly and daily records, the daily records are generally much shorter than the monthly records where they overlap, there were ubiquitous discrepancies between monthly records and monthly records derived from daily discharges for some sites generally, the daily discharges seem more reliable, but for at least one site, a block of daily discharges seemed to be for a different gauge • in early 2000, INAG did not seem to have definitive gauge records; hence, choosing amongst alternatives for these sites is a bit of a crap shoot • with a few exceptions noted below, hybrid records were constructed with the general order of acceptance as (1) monthly means from daily discharges, (2) monthly mean series from INAG, (3) monthly mean data from UNESCO sources, and (4) monthly mean data from an independent source Douro @ Regua WMO # PT EU • 9830 RIV # 994 River Gauge Douro Regua UNESCO has 1933–1968 171 • • • • • INAG gives monthly data for Oct 1939–Sep 1969, and daily data for Oct 1944 – Sep 1951 on the overlapping intervals these are somewhat contradictory INAG’s monthly series appears to have some significant typos the series retained is a composite of INAG daily and UNESCO monthly for 1933– 1968, with INAG monthly data for 1969 appended if INAG can ever produce a definitive series of daily data for the entire period of record, it would be best to retrieve the entire series and re-calculate the monthly means Mondego @ Coimbra WMO # PT EU 9827 RIV # 996 River Gauge Mondego Ponte S. Clara (Coimbra) • • • WMO and RIV have 1976–1984 an independent source (IND) has 1921–1971 and 1976–1984 INAG has monthly data from 1939–1985, and daily data from 1955–1985 • • IND data before 1939 have much higher mean level than from 1939 onward; hence, these were ignored INAG monthly and daily data from 1981–1985 have much higher mean level than from 1939–1980, including peak discharges that occur in the low flow season; hence, 1981–1985 INAG data were ignored • the UNESCO files have a few large typos • the retained series is a composite of daily/monthly data from INAG for 1939–1980 Tagus (Tejo) @ Vila Velha de Rodão WMO # PT EU 9832 RIV # 986 River Gauge Tagus (Tejo) Vila Velha de Rodão • this was the main long term gauge on the Tagus until 1973 when it was superseded by a gauge not too far downstream at Tramagal • • INAG and UNESCO records generally agree from 1939 onward for 1913–1936, the INAG monthly series has mean level ca. 17% higher than the UNESCO series; and INAG low season discharges are ca. 2-fold higher 172 • • the UNESCO series has virtually the same mean level before and after 1939; hence, there is reason to suspect that the pre-1939 INAG series is somehow corrupted the INAG series goes back to 1902; interested parties could calibrate the UNESCO and INAG series for concurrent data over 1913–1936, and extend the UNESCO series back to 1902 • • • • the UNESCO series seems to have a large typo in Mar 1947 the UNESCO discharge = 5,708 the INAG discharge = 1,975 otherwise, INAG and UNESCO are nearly identical from 1939–1968 • the series retained is a composite of UNESCO (1913–1938) and INAG (1939–1974) Europe: Romania Danube @ Ceatal Izmail WMO # RO EU • • • • 9763 RIV # 765 River Gauge Danube Ceatal Izmail UNESCO and independent sources agree on concurrent data for 1921-1984 MED-HYCOS gives daily data for 1921 – Oct 2000 that yields somewhat different monthly data, particularly before 1975 for some months discrepancies are relatively large; e.g., for Feb 1928, the recent MED-HYCOS record gives 4,793 m3/s while the other sources give 6,814 m3/s the MED-HYCOS version appears to be a revised version and is accepted Danube @ Orsova WMO # RO EU 9877 RIV # 772 River Gauge Danube Orsova • WMO, RIV, IHD and two independent versions generally agree except for a few errors that appear to be typos in R772 • • • for Apr 1884, IHD and R772 give 5850, while the others give 5880 for Nov 1974, R772 gives 9660, while the others give 8660 for Dec 1975, R772 gives 7450, while the others give 6450 • there is a potential disagreement between the UNESCO files and GRDC 173 • • • • for Oct 1870, GRDC and one independent source give 8870 the others give 4870 there is no resolution for this without access to source data however, Oct generally has the lowest discharges of the year, and a discharge of 8870 would be abnormal; hence, the UNESCO value is retained Mures @ Arad WMO # RO EU 9875 RIV # 211 River Gauge Mures Arad • • • IHD, W9875, and R211 have long historical records there are numerous differences before 1972 IHD and R211 agree except for rounding differences and a few typos • • W9875 and R211 disagree perceptibly on some records as shown below the greatest discrepancies occur in 1931 when RIV data seem low and may be from another gauge Jun 1931 discharge of 12.5 for W9875 seems to be a probable typo that was deleted [historical patterns suggest that given the May and July discharges, the June discharge could be anywhere from 80–400+ m3/s] • 1000 900 800 700 600 500 400 300 200 100 0 1929 1930 1931 1932 211 • 1933 9875 the two series also disagree from May–Nov 1947 when R211 seems too high for the low flow season 174 400 350 300 250 200 150 100 50 0 1946 1947 1948 211 9875 • there are similar, but smaller discrepancies in Aug-Dec 1958, Sep–Dec 1959, and • • discharge is highly erratic at this site; hence, all records are within plausible ranges most discrepancies occur in pre-1972 records which for R211 are the IHD data submitted to UNESCO 25 years ago • for the time being W9875 has been retained as a purely arbitrary choice • the latest version of the entire historical record should be retrieved from the Romanian source agency if the opportunity arises Europe: Serbia Danube @ Bezdan (Serbia) WMO # YU EU 9739 RIV # 756 River Gauge Danube Bezdan (Serbia) • • • WMO and RIV have 1950–1984 they agree except for what is most likely a typo in WMO MED-HYCOS has daily discharges for 1984–1999 • for Aug 1980, W9739 gives 3640 175 • • R756 gives 2640 comparison with the other Serbian Danube gauge at Bogojevo suggests that R756 has the correct value • at the time MED-HYCOS was accessed, the records available for 1993 and 1994 were identical 1993 was assumed to be correct, but these may be data for 1994 check MED-HYCOS for an update • • • the record retained is a composite of W9739 corrected for the typo above, and MED-HYCOS data from 1984–1999 excluding 1994 Danube @ Bogojevo (Serbia) YU EU WMO # RIV # River Gauge 9740 1380 Danube Bogojevo (Serbia) • • WMO and RIV have 1980–1984 they agree except for what is most likely a typo in RIV • • • for Mar 1983, R1380 gives 2489 W9740 gives 2849 comparison with the other Serbian Danube gauge at Bezdan suggests that W9740 has the correct value • W9740 is retained Sava @ Sremska Mitrovica (Serbia) WMO # YU EU 9742 RIV # River Gauge 207 Sava Sremska Mitrovica (Serbia) • • UNESCO sources have 1926–1984 MED-HYCOS has daily discharges for 1984–1999 • • • • there is a perceptible discrepancy between WMO and RIV in Oct 1943 R207 gives 566 W9742 gives 455 it is unclear which value is more correct • • most of 1976–77 disagrees between W9742 and R207 the differences are relatively small for most months and on an annualized basis 176 • with access to source data, it is unclear which record is more correct A M J J 956 962 6 1430 2170 1470 2210 40 40 1990 2030 40 1960 1980 20 874 887 13 2360 2880 2260 2890 -100 10 2160 2700 2330 2670 170 -30 1450 1450 0 753 783 30 708 744 36 R207 1976 W9742 1976 dif R207 1977 W9742 1977 dif J F 750 750 0 M A S O 1250 1240 1260 1240 10 0 709 765 56 900 920 20 N D mean 1050 1050 0 1850 3260 1980 3260 130 0 1565 1590 25 1140 1160 20 1440 1960 1400 1910 -40 -50 1597 1607 10 • for 1984, the UNESCO data disagree somewhat with the MED-HYCOS data • for the present, the record retained is a composite of W9742 to 1983 and MEDHYCOS from 1984–1999 if the opportunity arises, the entire historical record should be replaced with the latest version from Serbian authorities • Tisza (Tisa) @ Senta (Serbia) YU EU WMO # RIV # River Gauge 9743 1381 Tisza (Tisa) Senta (Serbia) • • WMO and RIV have 1980–1984 they agree except for what is most likely a typo in RIV • • • for Jan 1980, R1381 gives 407 W9743 gives 497 comparison with the upstream gauge at Szeged, Hungary, indicates unequivocally that W9743 has the correct value • W9743 is retained Velika Morava @ Lubicevsky Most (Serbia) WMO # YU EU • • 9738 RIV # 769 River Gauge Velika Morava Lubicevsky Most (Serbia) UNESCO sources have 1946–1984 with the exception of a few typographical errors, it appears that W9738 and R769 were constructed from the IHD records to 1972 with later data appended 177 • • MED-HYCOS has daily discharges for 1984–1999 GRDC also gives annual summary data to 1984 • from 1946–1976, there are numerous significant discrepancies among WMO, RIV, IHD and the GRDC annual summary it appears that the historical record has been revised several times the underlying record used by GRDC for the annual summary may be the most recent of the alternatives, and seems to be almost a different series entirely much of 1963 as given by WMO, RIV, and IHD may be wrong 1976 as given by RIV seems to be too high unfortunately, there is not much that can be done with the annual extrema and average • • • • • • from 1976–1984 all sources agree • for the present, the record retained is a composite of W9738 to 1983 with a few corrections and MED-HYCOS data from 1984–1999 if the opportunity arises, this entire record should be replaced with the latest version from Serbian authorities • Europe: Slovakia Danube @ Bratislava WMO # SK EU 9878 RIV # 754 River Gauge Danube Bratislava • UNESCO sources have data for 1900–1990 • • • Feb 1974 R754 discharge = 1,008 is an error W9878 gives 1,908 W9878 is consistent with the downstream gauge at Nagymoros, HU • • W9878 and R754 differ on Jul–Dec 1975 and through 1977 relative to the downstream gauge at Nagymoros, Hungary, the R754 cause a perceptible rise in the root-mean-square-difference between the two gauge records, while the RMSD between W9878 and Nagymoros remains stable W9878 is assumed to be correct • 178 W9878 R754 dif 1975 1975 1975 1975 1975 1975 7 8 9 10 11 12 4857 2482 1952 1252 1153 1147 4754 2339 1797 1120 1020 1015 103 143 155 132 133 132 1977 1977 1977 1977 1977 1977 1977 1977 1977 1977 1977 1977 1 2 3 4 5 6 7 8 9 10 11 12 1220 3242 2815 2645 2949 2246 2000 3066 1831 1170 1392 1495 1175 3187 2776 2598 2901 2204 1953 3019 1789 1101 1322 1426 45 55 39 47 48 42 47 47 42 69 70 69 Europe: Spain Warning: Mis-scaled UNESCO data • • four of five long term Spanish gauges have mis-scaled historical records up to 1962 only one gauge, Duero @ Villachica, appears to have a complete historical record of correctly scaled data WMO # ES ES ES ES RIV # River Gauge Area EU EU EU EU 9843 9844 9841 9842 735 990 983 195 Ebro Ebro Guadalquivir Jucar Tortosa Zaragoza Alcala del Rio Masia de Mompo 84,230 40,434 46,995 17,876 ES EU 9845 993 Duero Villachica 41,856 • • each of the four of the 4 affected records are missing 1963–1964 at each of these 4, the records from 1913–1962 have mean level from 2.5–5.6 times higher than the mean level from 1965–1984 179 mean discharge cms 10000 1000 100 19 13 19 16 19 19 19 22 19 25 19 28 19 31 19 34 19 37 19 40 19 43 19 46 19 49 19 52 19 55 19 58 19 61 19 64 19 67 19 70 19 73 19 76 19 79 19 82 10 Guadalquivir • • Ebro_Tortosa Ebro_Zaragoza Douro for 2 of 4 affected sites [Ebro @ Zaragoza, Jucar @ Masia del Mompo], a recent GRDC summary gives the series of annual mean and extrema that appear to be correctly given in m3/s (cms) for the other two sites, GRDC has the corrupted historical records the calibration plots of the concurrent months with the corresponding UNESCO series show that whatever is wrong with the old records is more complex than simple mis-scaling by incorrect units [if the problem were incorrect units, the data would fall along a straight line with little or no scatter] 250 Jucar @ Masia del Mompo 1912-1962 200 GRDC series cms • Jucar 150 100 y = 0.30x 50 0 0 100 200 300 400 UNESCO series units unknown 180 500 600 700 Duero @ Villachica / @ Tore (Toro ?) WMO # ES EU ES EU • • • • • RIV # 9845 9846 993 River Gauge Area Duero Duero Villachica Tore (Toro ?) 41,856 41,808 in 1980, the gauge appears to have been moved from Villachica to Tore (Toro ?) RIV gives a single composited record WMO gives the two distinct records the present set retains the two distinct records these can be safely spliced for operational purposes Ebro @ Zaragoza / Tortosa WMO # ES EU ES EU • • RIV # River Gauge 735 990 Ebro Ebro Tortosa Zaragoza 9843 9844 Area 84,230 40,434 UNESCO sources have data to 1984 for both gauges and are internally consistent data for late 1995 to late 1999 from MED-HYCOS were appended for both gauges Europe: Sweden Angerman @ Solleftea WMO # SE EU 9777 RIV # 205 River Gauge Angerman Solleftea • • UNESCO sources give 1965–1984 there are a few discrepancies between WMO and RIV • • two independent versions (IND1 and IND2) give 1909–1984 these agree on pre-1965 data, but seem to be copies of WMO and RIV on 1965– 1984 except for the case below • • • • • the largest potential discrepancies occur over May–Jun 1967 WMO, RIV and IND1 give 1,005 and 1,063 m3/s respectively for May and Jun IND2 gives 100.5 and 106.3 respectively either way, these would be the most extreme discharges ever for May and Jun if the higher values are valid, the May–Jun mean discharge of 1,034 exceeds the next highest May–Jun mean discharge of 764 by a large margin 181 • • if the lower values are valid, the May–Jun mean discharge of 103 is only marginally lower than the next lowest May–Jun mean discharge of 111 however, some limited data for a few streams in central Sweden (not in UNESCO files) suggest that discharges should have been near normal (ca. 400 ± 200 m3/s for the Angerman) in May–Jun 1967 • for the present May–Jun 1967 have been set to missing because the likely choices based on the given data appear unlikely given the contextual circumstances • • • • the other notable discrepancy occurs in May 1975 WMO gives 484 RIV gives 848 it is unclear which of these is correct; either value is plausible • the joint IND/WMO set was retained with May–Jun 1967 and May 1975 set to missing the WMO or RIV entries could be restored as desired • Lule @ Boden Waterworks WMO # SE EU • • • • 9778 RIV # 213 River Gauge Lule Boden Waterworks UNESCO sources give 1965–1984 an independent version (IND) gives 1900–1984 IND and UNESCO agree on concurrent months the joint IND/UNESCO set is retained Europe: Switzerland Rhine @ Basel (St. Alban) WMO # CH EU • • • • 9795 RIV # River Gauge 742 Rhine Basel (St. Alban) collectively, UNESCO sources give 1965–1984 and are in agreement an independent source (IND) gives 1808–1984 (1925 missing) and agrees on concurrent years IND is retained 1921 is suspiciously low, but Rhone @ Chancy (below) also had abnormally low discharge for 1921 182 Rhone @ Chancy WMO # CH EU • • • 9796 RIV # 198 River Gauge Rhone Chancy collectively, UNESCO sources give 1965–1982 and are in agreement an independent source (IND) gives 1905–1982 and agrees on concurrent years IND is retained Europe: UK Recent UK data now available on-line • click on “River Flow Data” at www.nwl.ac.uk/ih/nrfa/index.htm for recent [1996-1999 in early 2001] daily discharge data for ca. 210 UK gauges • click on “UK Gauging Station Network” at www.nwl.ac.uk/ih/nrfa/index.htm for gauge listings and metadata for the entire UK • numerous regional and river basin agencies [“Measuring Authorities”] monitor stream discharges in the UK the National River Flow Archive [NRFA] may not have all the stream discharge records that are available • • in 1999-2000, monthly data for 30 gauges in England and Wales were available at www.environment-agency.gov.uk/gui/dataset4/4nation.htm • • either data have been withdrawn, or the URL has moved the UK Environment Agency www site has become so cluttered it is very difficult to find anything Warning: Gauged versus Naturalized Discharge Data • • • for most gauges, UK agencies give both “gauged” and “naturalized” discharges “gauged” discharges are those measured at the gauges “naturalized” discharges are pseudo discharges created from gauged discharges adjusted for net upstream regulation, abstractions, return flows, etc. • “gauged” records are generally denoted by the 5-digit UK gauge code with “g” appended, e.g., Thames (gauged) @ Kingston has code 39001g 183 • “naturalized” records are generally denoted by the 5-digit UK gauge code with “n” appended, e.g., Thames (naturalized) @ Kingston has code 39001n • these alternate records would present no problem if correctly labelled; however, in most available non-UK sources the record identified Thames @ Kingston presents “naturalized” discharges if they were gauged discharges • data obtained from the National River Flow Archive [www.nwl.ac.uk/ih/nrfa/index.htm] will likely be identified correctly NRFA appears to follow a policy of explicitly identifying “naturalized” discharges when these are given, and records with no explicit indications [most records] are generally “gauged” discharges data obtained from other agencies may not be correctly identified • • Bedford Ouse @ Bedford UK EU WMO # RIV # River Gauge 9815 1377 Bedford Ouse Bedford • • WMO and RIV give 1980–1984 these agree except for a typo in RIV • • • • • for Jun 1983 RIV gives 104 WMO gives 10 a discharge of 104 would exceedingly abnormal the neighbouring rivers (Thames, Nene) show no abnormal discharges the Nene @ Orton gauge, which has discharges that almost parallel the Bedford Ouse @ Bedford (same magnitudes, same patterns), has a discharge of 10 m3/s for Jun 1983 down by more than 1/2 from May • the record retained has 1980-1984 from WMO and 1996-1999 from UK-NRFA Severn @ Bewdley WMO # UK EU • • 9807 RIV # 193 River Gauge Severn Bewdley Severn @ Bewdley monthly discharge data are available on-line from the UK Environment Agency 1921–1999 data from the UK Environment Agency replaced the old UNESCO record 184 Thames @ Kingston / Teddington [naturalized] WMO # UK EU • • • • • • • • • 9806 RIV # 196 River Gauge Area Thames (naturalized) Kingston Teddington 9,948 9,950 Thames River data widely available from most sources are almost invariably “naturalized” pseudo data see next section for discussion of differences between naturalized & gauged discharges at this site the long term Thames gauge is known as Kingston with a record beginning in 1883 and continuing to present if there is a gauge called Teddington, it is virtually co-located with Kingston and offers nothing new Thames @ Kingston monthly discharge data were available on-line from the UK Environment Agency recent 1996-1999 data were available from UK-NRFA the 1883 – 1999 Thames @ Kingston data replaced the old UNESCO Thames @ Teddington record Thames @ Teddington should be discarded; the 1980–1984 data are perceptibly lower than Thames @ Kingston and likely came from a different gauge upstream it is possible that the 1980-1984 fragment are “gauged” rather than “naturalized” discharges; however, the seasonal distribution is somewhat different than suggested by the long term mean and the 1996-1999 gauged record discussed in the next section Thames @ Kingston / Teddington [gauged versus naturalized] WMO # UK EU 9806 UK EU 10126 RIV # 196 River Gauge Area Thames (naturalized) Kingston 9,948 Thames (gauged) Kingston 9,948 • record 10126 has been added containing a 4 yr record segment from UK-NRFA of “gauged” flows for Thames @ Kingston • the table below shows reported differences between “naturalized” and “gauged” discharges given in m3/s in terms of annual volumes, the recent difference amounts to 0.75 km3/a, versus the long term difference of 0.4 km3/a • 185 • much of the difference is likely due to water withdrawn for drinking water and industrial supplies in the London area; some of this may return as effluent discharges below the Kingston gauge J F M A M J J A S O N D annual gauged naturalized 115 144 68 96 58 84 60 84 29 54 23 46 11 31 14 31 16 32 26 46 50 80 76 102 45 69 difference 29 28 26 24 24 23 20 17 17 20 30 26 24 gauged naturalized 126 138 122 134 102 114 74 87 52 65 36 48 23 35 21 32 23 34 38 50 71 83 100 112 66 78 difference 12 12 12 13 13 13 13 11 12 12 12 12 12 1996-1999 1883-1998 a a NRFA annual data sheets include long term summary statistics; only 1996-1999 gauged discharges are currently readily available Wharfe @ Flint Mill Weir UK EU • • WMO # RIV # River Gauge 9812 1374 Wharfe Flint Mill Weir Wharfe @ Flint Mill Weir monthly discharge data are available on-line from the UK Environment Agency Nov 1965 – mid 1999 data from the UK Environment Agency replaced the old UNESCO record 12.0 North America North America: USA • US data are treated separately — [click to go to Section 16.0 USA ] North America: Canada Canada: General Remarks • of 80+ plus sites, about 50 lie in the Canadian Arctic (Arctic Ocean, Hudson Bay and Ungava Bay) drainage areas 186 • recently, historical monthly discharges to the end of 1993 for 2000+ gauges in the Canadian Arctic drainage area were made available on R-arcticnet (www.Rarcticnet.sr.unh.edu/) • • data for the 50+ Arctic drainage sites in UNESCO files were replaced checks at several sites showed that the old UNESCO records had the usual scattered errata including assorted data entry and transcription errors, replications within and across sites, missing years, and were further outdated in several cases by retrospective revisions • • • two UNESCO records that were composites were split back to the original pairs of distinct records one record from R-arcticnet was added where gauge had been slightly moved these cases are noted below • some river names, gauge locations were corrected Assiniboine @ Brandon / nr Brandon WMO # CA NA CA NA • • 9513 10118 RIV # 292 River Gauge Assiniboine Brandon Assiniboine nr Brandon the UNESCO records are composites to 1973, the record is for a gauge that was located not far downstream: Assiniboine at Brandon with drainage area 86,000 km2 • station Assiniboine near Brandon with drainage area 85,100 km2 began operation in 1974 • for the present, the two distinct records were retained Back River WMO # CA NA • • 9480 RIV # River Gauge 294 Back d/s Deep Rose Lake u/s Hermann River Area 98,200 93,900 the metadata for this record are wrong in all UNESCO sources the gauge location and area are given above, i.e., Back @ u/s Hermann River Columbia @ Birchbank 187 CA NA CA NA • • WMO # RIV # River Gauge 9503 9526 Columbia Columbia Birchbank International Boundary 1156 275 1980 data in R1156 are for the downstream site W9526 Columbia @ International Boundary W9503 has correct data for Birchbank Columbia @ International Boundary — Deleted WMO # RIV # 9526 9617 • • • USGS # 275 12399500 Lat Columbia Columbia International Boundary, BC International Boundary, WA CA US Lon Area km2 El m 49.00 -117.63 49.00 -117.63 155,000 154,622 400 396 these two records are essentially the same gauge record that appear in the catalogues of both Canada and the USA the nominally Canadian version was dropped in favour of the US version which is updated annually click to go to US: Columbia @ International Boundary Gods River CA NA • • WMO # RIV # River Gauge 9713 1094 Gods Lake outflow Gods Lake outlet Gods d/s Allen Rapids Area 25,900 the metadata for this record are wrong in all UNESCO sources the correct name and location are as given above, i.e., Gods @ d/s Allen Rapids Harricana @ Amos CA NA CA NA • • • WMO # RIV # River Gauge 9928 10119 1172 Harricana Harricana Amos Amos-2 the second record is the older gauge that operated from 1914–1933 both records have some data in 1933 that are nearly identical the Canadian catalogue gives the same drainage areas for the two, but the coordinates differ slightly 188 Kootenay / Kootenai @ nr Copeland, ID — reassigned to USA & replaced US NA • • • WMO # RIV # River Gauge 9505 Kootenay nr Copeland ID 278 Kootenay is the name used in Canada, while Kootenai is used in the US this gauge is listed in both US and Canadian catalogues, but is south of the US– Canada border in Idaho US authorities discontinued this gauge in 1992 • • in UNESCO files, the gauge is falsely listed as Canadian for the present set the record was replaced with another US Kootenai gauge in close proximity • click to go to US: Kootenai • • • the USGS record for Kootenai nr Copeland spans 1929–1992 data in UNESCO files span 1929–1984 and have scattered errata there are three decimal shift typos in the UNESCO files (W9505 and R278) • • for Jan 1970, UNESCO discharge = 950 is a typo USGS gives 94.7 • • for Nov 1973, UNESCO discharge = 4980 is a typo USGS gives 498 • • for Dec 1973, UNESCO discharge = 3710 is a typo USGS gives 371 • N.B. the flow regime changed appreciably from late 1973 as a major reservoir began operation and effectively damped out the natural seasonal cycle Moose @ Moose River / u/s Moose River WMO # CA NA CA NA • • 9490 9491 RIV # 302 River Gauge Moose Moose Moose River u/s Moose River Lat Lon Area 50.82 50.74 -81.30 -81.46 61,100 60,100 the original gauge was at the settlement of Moose River [WMO called this Moose River Crossing] beginning in 1982, the gauge was moved upstream of the village 189 • • • • • WMO gave the two records separately, but RIV gave only the composited record R302 the distinct records as given in R-arcticnet are retained the drainage areas given in the Water Survey of Canada catalogue are identically 60,100 km2 some informal sources give the downstream gauge a larger area of 61,100 km2 the two sites are far enough apart that the difference in drainage areas could be 1,000 km2 or more Natashquan CA NA CA NA CA NA WMO # RIV # River Gauge Area Period 9499 9502 9498 1171 1329 325 Natashquan Natashquan Natashquan en aval de la Riviere Natashquan Est 11,600 1966-1983 en aval de la decharge du Lac Aliecte 15,600 1980-1990+ pres de l'embouchure 16,000 1962-1972 • • • • as given: W9499/R1171 span 1976–1983 W9502/R1329 span 1980–1984 W9498/R325 span 1966–1975 • data for Natashquan @ en aval de la Riviere Natashquan Est and Natashquan @ pres de l'embouchure are muddled • for Natashquan @ pres de l'embouchure, both WMO and RIV somehow give data for 1966–1975, when the gauge ceased operation in 1972 the only gauge operational over 1973–1975 was Natashquan @ en aval de la Riviere Natashquan Est • • • • • to compound problems, W9498 data for 1972–1975 (nominally Natashquan @ pres de l'embouchure, but most likely Natashquan @ en aval de la Riviere Natashquan Est) are muddled and should be ignored R325 has 1973–1975 and 1972 is missing the mean annual discharge for R325 during 1973–1975 is 246 m3/s while the mean for 1976–1983 at the upstream gauge Natashquan @ en aval de la Riviere Natashquan Est is 317 m3/s, and the mean at Natashquan @ pres de l'embouchure for 1966–1971 is 418 m3/s the neighbouring Petit Mecatina had comparably lower discharges for 1973–1975 relative to previous and following years; hence, the 1973–1975 data in R325 likely belong to W9499/R1171 Natashquan @ en aval de la Riviere Natashquan Est 190 • • thus, the record retained for Natashquan @ pres de l'embouchure spans Jul 1964 – Dec 1971 this includes Jul 1964 – Dec 1965 from an independent historical compilation • 1973–1975 data from R325 were pre-pended to the record for Natashquan @ en aval de la Riviere Natashquan Est which then spans 1973–1983 • R1329 Natashquan @ en aval de la decharge du Lac Aliecte (below Lake Aliecte outlet) has a typo for Mar 1984, R1329 discharge = 10 W9502 gives 107 • • Petit Mecatina CA NA CA NA WMO # RIV # River Gauge 9500 9501 Petit Mecatina Petit Mecatina WSC site 02KA006 en aval du Lac Breton 327 1330 Area 19,100 12,100 • the gauge at site R327 ceased in 1980 • data given in R327 after 1980 are for site R1330 • the RIV catalogue gave drainage area for R1330 incorrectly as 17,000 km2, not 12,100 km2 as reported by Water Survey of Canada Saint John @ Pokiok / d/s Mactaquac CA NA CA NA WMO # RIV # River Gauge 9525 9534 322 1026 Saint John Saint John Pokiok d/s Mactaquac Lat Lon Area 45.97 45.96 -67.24 -66.83 38,800 39,900 • • the upstream gauge (Pokiok) operated to 1967 the downstream gauge began operations in 1968 • • the two records are close enough to be composited with minor adjustment a dam and hydroelectric generating station were constructed during the 1970s at Mactaquac Saint-Maurice @ Centrale de Grande-Mere WMO # RIV # River Gauge 191 CA NA 9522 1170 Saint-Maurice Centrale de Grande-Mere • both WMO and RIV have identical data for 1936 and 1937 • both are missing 1968–1970 • an independent source gives the correct data for 1937 and 1968–1970 • • • all versions of this record have some highly suspect historical data the discharges reported for Sep 1933–1938 and Oct 1933–1934 are abnormal excluding these aberrant data, the next highest discharges are 1060 and 1660 for Sep and Oct respectively in ca. 80 years of record 1933 1934 1935 1936 1937 1938 • • • • J F M A M J 357 187 241 221 507 241 291 201 195 192 379 300 241 215 348 863 320 509 1650 951 908 1010 1010 1770 2270 2360 1430 3250 2040 1840 719 863 999 1370 679 685 J A 235 383 620 297 651 331 617 416 300 345 453 1080 S O N D 2490 3030 3990 3740 3880 543 4060 976 4130 651 8010 676 232 439 628 753 911 535 212 501 303 509 524 391 some exceedingly high discharges are also reported for Apr–May 1923–1924 and May 1928, these are the high discharge months these aberrant data have been retained for the present, but this record should be reviewed with Canadian sources when the opportunity arises with 80+ years of data, the effect on coarse summary statistics is not great; however, sensitive analyses would almost certainly be affected St. Lawrence @ Cornwall WMO # USGS # 9492 9550 • • • River gauge name Lat St Lawrence Cornwall Lon Area Alt mean flow km2 m m 3/s CA 45.00 -74.80 774000 47 241.8 4264331 St Lawrence Cornwall ON nr Massena, NY US 45.00 -74.78 774410 -99 226.9 between WMO and other sources, the Canadian record for Cornwall, ON spans 1958–1988 with 27.5 net years. US Cornwall/Massena record spans 1934–1998 data are identical to concurrent US Cornwall/Massena data except for minor numerical jitter —the two records likely represent the same discharge records for 192 • • the Cornwall/Massena electrical generating station barrage / navigation lock system. according to US notes, data are developed jointly by Canadian and US authorities the Canadian version of the data was excluded in favour of the longer (1934–1999) US records. [Click to go to US: St. Lawrence @ Cornwall/Massena]. Stikine @ Telegraph Ck / Porcupine @ Old Crow WMO # CA NA CA NA • • • 9469 9472 RIV # 264 260 River Gauge Stikine Porcupine Telegraph Creek Old Crow 1979 data are identical at both sites in WMO Stikine is the correct location 1979 Porcupine data were taken from R260 Thompson @ nr Spences Bridge WMO # CA NA 9917 RIV # 273 River Gauge Thompson nr Spences Bridge • • this record is available only in R273 which has 1966–1979 GRDC has given monthly summary stats for 36 years • • • the Nov–Dec 1973 data given by R273 are wrong both exceed historical maxima recorded for 1952–1988 from GRDC summary statistics and the pattern of discharge in adjacent months, the Nov–Dec discharges should each be less than 391 m3/s and greater than 243 m3/s with an average of about 320 m3/s for the two months as they could not be determined exactly, Nov–Dec 1973 were setting to missing values • 1973 11 1973 12 R276 mean max 1680 1130 405 292 770 522 North America: Mexico Warning: Dubious records at some gauges • data for some gauges in the Usumacinta (Chixoy) in Guatemala and adjacent Candelaria watershed (Mexico) seem to be 10-fold too low 193 • • • drainage areas and / or discharge data may be in error or incorrectly assigned to these sites drainage areas should be delineated from good quality DEMs if possible the watersheds of the San Pedro tributary of the Usumacinta and the Candelaria extend on to the karstic terrain of Yucatan peninsula where most rainfall is lost to the subsurface and may be transported out of the surface watersheds, i.e., the groundwatersheds may differ appreciably from the surface watersheds; hence, low specific runoff may be legitimate WMO # GT GT GT GT MX River Gauge Area Discharge 3 km2 km CA CA CA CA NA 9692 9698 9693 9696 9626 Chixoy (Usumacinta) Chixoy (Usumacinta) La Pasion San Pedro Usumacinta Las Torres San Augustin El Porvenir San Pedro Mactun Boca del Cerro MX NA 9655 Candelaria Candelaria Runoff mm 5,509 10,910 11,875 10,820 50,743 1.39 16.75 12.13 1.34 58.74 253 1,536 1,021 124 1,158 9,628 1.32 137 Conchos @ Ojinaga MX NA • WMO # RIV # River Gauge 9646 1097 Conchos Ojinaga short WMO & RIV records were replaced with the entire historical record (1954 – Jan 1999) courtesy of the US-Mexico International Boundary Water Commission Grijalva @ Reforma / Rompido de Samaria @ Samaria • data given for W9656 / R1079 (Rompido de Samaria) are almost surely for the site designated W9654 / R1078 (Rio Grijalva @ Reforma) • for the present, UNESCO data mis-labelled as Rio Grijalva @ Reforma have been re-labelled Rompido de Samaria @ Samaria; however, these data may be from some other gauge • because the correct stream name, location and drainage area are unavailable for these data, this record may best be deleted for most purposes this was retained on the chance that someone may know just what this record represents • 194 • in the table below, the green-shaded entries show what is given in the raw WMO and RIV catalogues, and the yellow-shaded entries show how the sites have been entered in the present catalogue WMO # • • RIV # River Gauge Lat Lon alt area m km 2 annual runoff discharge km 3 mm 9654 1078 Grisalva Reforma 16.35 -93.23 18 37,702 4.6 121 9656 1079 Rompido de Samaria Samaria 17.98 -93.30 20 37,702 19.0 504 9654 1078 Rompido de Samaria Samaria 17.98 -93.16 -9 -9 4.6 9656 1079 Grijalva Reforma 17.96 -93.16 20 37,702 19.0 504 Rio Grijalva is a sizable basin of ca. 40,000 km2 and annual discharge of 20–25 km3 before joining a distributary of the Usumacinta River in the swampy coastal lowlands and discharging to the Gulf of Mexico (some Mexican sources consider the Grijalva to be a tributary of the Usumacinta) annual discharge, drainage area, and specific runoff at W9656 / R1079 are about right for Rio Grijalva @ Reforma, and the town of Reforma is found at the revised coordinates near the location given by UNESCO for Samaria • also, the Grijalva system is highly regulated by several large reservoirs upstream, so what would be strong seasonally cyclic discharges under natural conditions are absent in both Rompido and Grijalva data • • it is unclear precisely what Rompido de Samaria @ Samaria represents neither Samaria nor Rompido de Samaria can be found in any gazetteers or maps that were available • as the figure shows, Rompido discharges on the overlapping 1976–78 period are closely correlated to Rio Grijalva, i.e., monthly discharges at one could be roughly predicted from the other, and vice versa because discharges at Rompido de Samaria @ Samaria are so closely correlated to Rio Grijalva and similarly lack the natural seasonal cycle, this record my represent a canal (water supply, irrigation perhaps) feeding off the Grijalva rather than a natural stream, or possibly a particular channel of the Grijalva in the lowland swamps • • geographic coordinates supplied for Rompido de Samaria @ Samaria are bogus; it was arbitrarily placed a bit north of Reforma to allow it to be plotted on a map near Grijalva @ Reforma — the actual locale could anywhere along the lower Grijalva upstream or downstream of Reforma 195 250 RIV 1078 m3/s 200 150 100 50 300 400 500 600 700 800 900 3 RIV 1079 m /s • • finally, the Feb 1977 Rio Grijalva discharge is a typo in both WMO and RIV this was changed to 560 m3/s, but you may want to simply delete it 1976 1977 1978 1979 1980 J F M A M J J A S O N D 420 416 574 601 438 336 5.6 576 608 810 374 633 527 592 785 429 604 723 476 760 404 663 681 520 804 373 627 834 645 823 437 506 486 640 363 459 471 407 651 428 511 330 468 953 538 650 533 679 715 514 693 898 514 630 703 642 687 536 885 324 San Pedro @ San Pedro WMO # MX NA • • • 9636 RIV # 1336 River Gauge San Pedro San Pedro R1336 spans 1980–1982 W9636 spans 1976–1981 with Jan–May 1981 missing between the two, there is a complete record for 1976–1982 Usumacinta @ Boca del Cerro — WARNING mis-scaled 1965–1968 data WMO # RIV # River Gauge 196 MX NA 9626 338 Usumacinta Boca del Cerro • • • • R338 spans 1969–1983 IHD spans 1965–1972 W9626 spans 1965–1983 an independent set (IND) spans 1947–1983 • 1965–1968 data in W9626, IHD and GRDC must be multiplied by 10 to bring them to the proper scale • at the proper scale, 1965–1968 data for W9626 differ somewhat from concurrent data in IND, i.e., these are similar but different versions of the same record with most discrepancies at 0-3%; in two months differences exceed 10% J F M A M IND 9626 dif 1965 1690 1150 1965 1650 1150 40 0 812 790 22 547 540 7 471 470 1 692 2450 2180 2620 4630 4290 2170 780 2470 2280 2740 4540 4180 2130 -88 -20 -100 -120 90 110 40 23702 23720 -18 IND 9626 dif 1966 2070 1330 1180 1260 1040 1950 3810 2230 3930 4090 2620 1510 1966 2030 1330 1190 1230 1000 2170 3670 2320 4040 4090 2570 1470 1966 40 0 -10 30 40 -220 140 -90 -110 0 50 40 27020 27110 -90 9626 IND dif 1967 1290 1250 980 1967 1260 1250 1010 1967 30 0 -30 830 840 -10 520 1210 2610 2590 1950 5010 3400 1740 524 1190 2580 2610 1840 5130 3490 1780 -4 20 30 -20 110 -120 -90 -40 23380 23504 -124 IND 9626 dif 1968 1480 1270 1968 1490 1300 1968 -10 -30 656 650 6 582 2350 2460 3190 3260 3750 2960 2210 650 2320 2540 3170 3330 3810 2880 2180 -68 30 -80 20 -70 -60 80 30 25007 25140 -133 • 839 820 19 J J A S O N D for present purposes, IND was accepted for 1947–1983 13.0 Caribbean Caribbean: Cuba Four sites with data not in UNESCO • • an independent source for the four site below has 1-2 years before 1965 that are not in UNESCO files these data are included in the present set, but could not be corroborated CU CB WMO # RIV # River Gauge 9667 1068 Damuji Rodas 197 CU CB CU CB CU CB 9668 9666 9665 332 243 258 La Rioja San Cristobal San Diego Moscones La Campana Los Gavilanes Caribbean: Dominican Republic Yuna @ El Limon WMO # DO CB • • 9657 RIV # River Gauge 1184 Yuna El Limon R1184 Feb 1984 discharge = 12 is likely an error W9657 and an independent source give 132 14.0 Central America Central America: El Salvador Grande de San Miguel @ Vado Marin / @ Las Conchas SV CA SV CA WMO # RIV # River Gauge 9687 9691 334 1067 Grande de San Miguel Vado Marin Grande de San Miguel Las Conchas Lat Lon Area El 13.30 -88.30 13.28 -88.41 1,900 2,238 20 7 • the table above gives the final catalogue entries for 2 sites with usable data • drainage areas remain somewhat uncertain as discussed below • IHD, W9687 and R334 have records for Vado Marin that are identical when they overlap, and together give 108 months of records spanning 1966–81 • independent sources have two versions of the Vado Marin record which give data for 1965, 1975, and 1977–1978 not in the UNESCO files • W9691 and R1067 are identical when they overlap, and together give 44 months of record spanning 1976–81 • R1067 river and gauge name were incorrectly reversed in the RIV site catalogue entry, i.e., listed as Las Conchas @ Grande de San Miguel • R1331 is labelled Grande de San Miguel @ Las Conchas • R1331 contains 4 years of entries: 1976-77 that are data from the neighbouring Rio Lempa with nearly 10-fold higher discharges, and 1980-81 that are identical to W9691 and R1067 198 • R1331 was deleted • independent sources give 3 versions of Las Conchas @ Grande de San Miguel including one with the river and gauge name reversed as in RIV • one of the independent versions gives data for May 1969 — Dec 1975, not in the UNESCO files; these data observe the same relationship vis-à-vis Vado Marin data as seen in data found only in UNESCO files, so they appear to be valid Problems 1. all versions of the Vado Marin record incorrectly give Oct 1973 as 14.0 • according to Las Conchas, the neighbouring Rio Lempa and other independent data, Oct 1973 should be ca. 140 2. the same 1980 data are given for both Las Conchas (four versions) and Vado Marin (only once, other versions are missing 1980) • the 1980 data are assumed to belong to Las Conchas 3. in 1979, there are 2 potential discrepancies between Vado Marin and Las Conchas • the Las Conchas discharges for Jul and Sep may be too high, or conversely the Vado Marin discharges may be too low • otherwise, all other concurrent Vado Marin and Las Conchas data fall nearly along a straight line when plotted against each other • though relations are reasonably good with neighbouring Rio Lempa @ San Marcos, they are inadequately precise to clarify these two cases • data were left as is Vado 1979 Conchas 1979 J F M 4.7 9.1 4.8 5.8 3.0 5.1 A M J J A S O N D 6.6 9.9 38.1 48.8 38.6 103.0 84.0 31.0 10.8 7.9 13.1 48.5 88.8 52.4 184.0 118.0 39.8 16.9 Muddled Metadata • R1331 and one independent record for Las Conchas have the river and gauge name reversed, i.e., Grande de San Miguel @ Las Conchas • these two records have muddled data from Las Conchas, Vado Marin and Rio Lempa @ San Marcos • Vado Marin and Las Conchas must be close together not far above the outlet to the Pacific • Vado Marin was not found in any gazetteers, but it has to be upstream of Las Conchas, i.e., discharges are smaller and gauge elevation has been consistently given as 20 m versus 7 m for Las Conchas 199 • • • • drainage areas remain somewhat uncertain areas for Vado Marin are given as 1,900 and 2,350 km2 areas for Las Conchas are given as 2,238 and 2,350 km2 independent sources put the total basin area above the outlet to the Pacific Ocean as 2,300–2,400 km2 • this suggests that: • Vado Marin area is ca. 1,900 km2, • Las Conchas area is ca. 2,238 km2, • total catchment area is ca. 2,350 km2 • these numbers may be off, but should be good enough for working purposes Lempa @ Colima SV CA SV CA • • WMO # RIV # River Gauge 9689 9688 1463 333 Lempa Lempa Colima San Marcos the Colima record only spans Jan 1969 – Apr 1975 W9689 and R1463 incorrectly include the much higher 1980 discharge from San Marcos downstream Lempa @ San Marcos WMO # SV CA RIV # 9688 333 River Gauge Lempa San Marcos • between UNESCO and independent sources, there are consistent data spanning 1965–1980 with scattered missing months • • • Oct 1966 from the independent data source, is a typo Oct 1966 has been assumed to be 581 not 58.1 nearest neighbours (Paz @ Hachadura and Grande de San Miguel @ Vado Marin) suggest that the Lempa Oct 1966 discharge should be as high or higher than Sep 1966 discharge, but 581 is within the range of plausible variation J F M A M J J A S O N D 9688 1966 40.5 40.9 40.8 45.9 228.0 679.0 1070.0 823.0 716.0 58.1 88.5 53.3 9690 1966 11.2 9687 1966 6.6 10.4 10.0 6.0 4.4 11.0 5.5 32.9 18.6 18.0 8.9 • 18.9 16.6 11.6 90.2 62.5 112.0 57.0 35.9 48.5 54.1 74.7 74.8 some may prefer to set Oct 1966 to missing, but the discharge of 58.1 is almost surely a significant error that should not be restored 200 Paz @ La Hachadura SV CA • • • WMO # RIV # River Gauge 9690 1075 Paz La Hachadura UNESCO sources only give 42 months from 1976–1981 independent sources give the record from Jan 1965 – Apr 1981 with some scattered missing months the independent data are internally consistent, and generally consistent with concurrent data from Lempa @ San Marcos and Grande de San Miguel @ Vado Marin Central America: Guatemala Warning: Dubious records at some gauges • • • • • data for some gauges in the Usumacinta (Chixoy) in Guatemala and adjacent Candelaria watershed (Mexico) seem to be 10-fold too low drainage areas and / or discharge data may be in error or incorrectly assigned to these sites drainage areas should be delineated from good quality DEMs if possible the watersheds of the San Pedro tributary of the Usumacinta and the Candelaria extend on to the karstic terrain of Yucatan peninsula where most rainfall is lost to the subsurface and may be transported out of the surface watersheds, i.e., the groundwatersheds may differ appreciably from the surface watersheds; hence, low specific runoff may be legitimate data for Chixoy @ Las Torres are almost surely wrong; this site is in the highlands not down in the Yucatan WMO # GT GT GT GT MX River Gauge Area Discharge 2 3 km km CA CA CA CA NA 9692 9698 9693 9696 9626 Chixoy (Usumacinta) Chixoy (Usumacinta) La Pasion San Pedro Usumacinta Las Torres San Augustin El Porvenir San Pedro Mactun Boca del Cerro MX NA 9655 Candelaria Candelaria 201 Runoff mm 5,509 10,910 11,875 10,820 50,743 1.39 16.75 12.13 1.34 58.74 253 1,536 1,021 124 1,158 9,628 1.32 137 Chixoy @ San Augustin / La Pasion @ El Porvenir GT CA GT CA WMO # RIV # River Gauge 9698 9693 1436 1438 Chixoy La Pasion San Augustin El Porvenir • N.B. Chixoy is the Guatemalteco / Maya name for the Usumacinta • for Chixoy @ San Augustin: a) R1436 has only 1976 b) W9698 has 1976 and May 1980 – Dec 1984 • for La Pasion @ El Porvenir: a) R1438 has 1976–1978 b) W9693 has 1976–1978 and the same May 1980 – Dec 1984 data given by W9698 for Chixoy @ San Augustin • these two gauge represent drainage areas of about the same size and have discharges of similar magnitudes; hence, it is not obvious which records have the correct data • for the present, records W9698 is retained for Chixoy @ San Augustin and R1438 is retained for La Pasion @ El Porvenir the choice is arbitrary • San Pedro @ San Pedro Mactun GT CA • WMO # RIV # River Gauge 9696 1335 San Pedro San Pedro Mactun Nov 1981 of R1335 should be 131 not 13.1 Central America: Nicaragua Warning: GRDC muddle • GRDC gives summary data for five of the gauges in UNESCO files: NI CA NI CA NI CA WMO # RIV # River Gauge 9699 9708 9700 1065 254 Coco Coco Grande de Matagalpa Guanas Corriente Lira Paiwas 202 Lat Lon Area 13.50 13.53 12.78 -85.95 -85.83 -85.12 5,510 6,830 6,500 NI CA NI CA • • • • • • • 9710 9705 1063 256 Grande de Matagalpa San Juan San Pedro del Norte El Castillo 13.07 11.01 -84.68 -84.40 15,073 28,600 although they appear to be more recent, GRDC summary data for the first four of these are inconsistent with concurrent data in the UNESCO files (WMO, RIV, IHD) and an independent source annual means are similar to UNESCO data for concurrent years, but the timing magnitude of seasonal peaks differs perceptibly it is unclear what is wrong, but the limited UNESCO data are internally consistent (highs and lows occur at the same months across the watersheds) and there is good reason to believe that the problem lies with GRDC GRDC summary stats and UNESCO data agree only for San Juan @ El Castillo N.B. the GRDC catalogue gives the drainage area for this gauge as 28,600 km2 versus 32,819 km2 given by UNESCO files the UNESCO area is wrong; El Castillo is not far downstream from the outlet of Lake Managua [drainage area 23,848 km2 including lake surface] and the total basin area is only 34,785 km2 according to an OAS [Organization of American States] hydrologic study the OAS gives a 19 yr (1969-1987) average annual runoff for El Castillo of 410 mm versus 461 mm from the 7 yrs of data available in UNESCO files Viejo @ La Lima / Santa Barbera WMO # NI CA NI CA • • • • • 9707 9706 RIV # River Gauge Area 248 247 Viejo Viejo La Lima Santa Barbara 855 1,197 IHD and RIV called this the “Viego” both WMO and RIV give wrong, but somewhat different coordinates for these two gauges !!! as given in WMO, the stream would have to cut laterally across the upper reaches of Rio Grande de Matagalpa for Nicaragua, the NIMA gazetteer gives many streams named Viejo, many places named Santa Barbara, and one place named La Lima ; but none make any sense for this river WMO coordinates were left as is, but these are almost surely wrong !!! Tamarindo @ Tamarindo NI CA WMO# RIV# River Gauge 9704 Tamarindo Tamarindo 203 km2 mm 306 301 206 447 • • • • • GRDC gives 206 km2 for the drainage area while all other sources give 306 km2 the difference has a large effect on specific runoff it’s unclear which area is correct the total basin area is only ca. 320 km2 NB — small streams on the narrow Pacific coastal strip of Nicaragua have lower specific runoff due to lower rainfall and porous volcanic soils 15.0 South America South America: Argentina • • • • • Argentina has much arid to semi-arid terrain; hence, numerous endorheic drainage systems alternate sources may give some drainage areas that differ radically from those herein according to beliefs about whether certain closed systems contribute, if only rarely, to adjacent or surrounding open systems Argentina also has many dams the discharges of some are among the records in this data set the Catálogo de Lagos y Embalses de la Argentina (Data Book of Lakes and Reservoirs in Argentina) [www.mecon.gov.ar/lagos/ind.htm] is a helpful source of information General Remarks — UNESCO data sources • • • • • Argentina has data from all three UNESCO sources amongst UNESCO sources, RIV and IHD are most often identical where they overlap, but RIV usually has more recent data while often lacking earlier IHD records the RIV/IHD combination are often somewhat different that WMO from 1–3 alternate records are available for many of these gauges from 3 independent sources in several cases, 1 independent record is largely identical to RIV/IHD (and often longer), while the other 2 are largely identical to WMO, reducing the alternatives to two choices for which there is no obvious best choice General Remarks — R-Hydronet 204 • • • a set of ca. 304 gauge records for Argentina have been made available at RHydronet [www.R-hydronet.sr.unh.edu/] as of early 2000 for 15 of 18 gauges in UNESCO files, records were replaced with R-Hydronet data that generally are both more recent and historically longer some R-Hydronet data are suspect, e.g., the latter part of the Sali Dulce record (see below) • N.B. to obtain the discharge data, the entire Argentine data collection including temperature, rainfall and discharge must be downloaded from R-Hydronet • Warning: many R-Hydronet drainage areas are wrong; many of the same metadata are likewise in correct for Argentine gauges in a gauge inventory compiled for the Rio Parana basin by Brazilian sources, i.e., errata in R-Hydronet metadata likely trace back to Argentine sources Warning: Confusing River Names & Muddled Records • in Argentina, there are numerous cases where two or more rivers have the same name, .e.g., there are several rivers called Salado • there are several systems where different reaches have different names, but the reach names are often not used consistently • several river and gauge names in the present set are somewhat muddled in the source files • • • Rio Pasaje and Rio Juramento are generally the same river by different names not too far downstream, these become Rio Salado (one of several in Argentina) some Argentinean literature refers to the system as the “Rio Pasaje-JuramentoSalado” • the river identified as “Dulce” in UNESCO sources is known as Rio Sali Dulce in some Argentinean sources; the upper reach may be known locally as the Sali and the lower reach known locally as the Dulce • Rio Tercero becomes the Rio Carcaraña in the lower reaches • UNESCO sources have muddled data for two different gauges (Paso Limay and Paso Miraflores) on Rio Limay independent sources appear to have correctly given distinct records for these • 205 • RIV and WMO give data for gauges nominally labelled Parana @ Corrientes that may be for different gauges not too far apart on the Parana – see section on Parana @ Corrientes Bermejo @ Zanja del Tigre WMO # AR SA 9453 RIV # 502 River Gauge Bermejo Zanja del Tigre • • there are two alternate versions of the Bermejo @ Zanja del Tigre record available RIV, IHD and one independent source give generally the same version of the record spanning Jan 1968 – Dec 1980 • • • the most authoritative version appears to be given by R-Hydronet this spans Sep 1940 – Aug 1980, but is missing Sep 1986 – Aug 1987 WMO, two independent versions, and GRDC summary data have Sep 1940 – Aug 1980 one of the independent versions begins in Jan 1939 WMO and the two independent versions are mostly identical to R-Hydronet except for a few typos • • • • the two alternatives differ on most months between Jan 69 – Aug 72, and on Sep, Nov and Dec 1975 most of the discrepancies are small, three are relatively large, and two of these seem more likely to be errata in the RIV/IHD version • • • WMO & GRDC have the following errata Apr 1941 discharge of 541 m3/s should be 241 m3/s Sep 1975 discharge of 13 m3/s should be 43 m3/s • the longer, R-Hydronet version was accepted with Jan 1939 – Aug 1940 pre-pended from one independent version Chimehuin @ Huechulaufquen WMO # AR SA • 9448 RIV # 448 River Gauge Chimehuin Huechulaufquen the joint RIV / IHD record spans 1968–1973 206 • W9448 record spans Jan 1936 – Mar 1975 and disagrees somewhat with the RIV / • • average differences were small, but R448 was perceptibly higher on 10 months R-Hydronet spans Jan 1936 – Mar 1994, but has numerous missing months from 1983 onward R-Hydronet data are identical to WMO to 1971 from 1971–1975, R-Hydronet data are slightly lower than WMO it appears that RIV/IHD, WMO and R-Hydronet represent successive revisions of the record with R-Hydronet being the most recent • • • • R-Hydronet was accepted Colorado @ Buta Ranquil WMO # AR SA 9446 RIV # 480 River Gauge Colorado Buta Ranquil • IHD and RIV give 1968 – 1979 • W9446 spans Apr 1940 – Jun 1980 • R-Hydronet has Apr 1940 – Jul 1994 • WMO & R-Hydronet agree perfectly on Apr 1940 – Jun 1980 • IHD/RIV differ from WMO/R-Hydronet over Jul 1968 – Aug 1975 • the discrepancies are generally small (<3%), but a few reach 10% • IHD/RIV were likely provisional data that have since been revised • R-Hydronet was retained Colorado @ Pichi Mahuida WMO # AR SA • • • 9912 RIV # 494 River Gauge Colorado Pichi Mahuida UNESCO Area Fekete et al. 22,300 69,068 there is a large discrepancy between the drainage areas given by UNESCO and Fekete et al. this is explained by a large system to the north that appears to function mostly as an endorheic (closed) system, but occasionally discharges into the Colorado specifically, the Rio Desaguadero-Salado and Rio Atuel discharge from the north onto swampy plain and salars north of the Colorado 207 • some maps show an ephemeral link from the swamps/salars to the smaller Rio Curaco which joins the Colorado just above Pichi Mahuida • the UNESCO area is retained for the present; this likely represents the effective drainage area in most years • • • • • • RIV / IHD have consistent data from Jan 1965–Jun 1972 the record is not in WMO GRDC summary data give 1918–1980 an independent source gives 1949–1952, and Jan–Jun 1980 R-Hydronet gives 1918-1994 all records agree on concurrent months • R-Hydronet is retained Limay @ Paso Flores WMO # AR SA • • 9450 RIV # 477 River Gauge Area Limay Paso Flores 9,800 • • WMO and an independent source span Apr 1941 –Mar 1980 R-Hydronet has the same data plus Apr 1980 – Oct 1983 minus scattered missing months IHD and RIV have Jan 1965– Mar 1971 RIV has 1973–1979 • for 1965–68, R477 data are for the Rio Limay gauge downstream at Paso Limay • WMO/GRDC have the following errata • • for Feb 1950, WMO/GRDC discharge = 940 is a typo R-Hydronet gives 940 • • for Mar 1950, WMO/GRDC discharge = 730 is a typo R-Hydronet gives 73 • • for Jan 1957, WMO/GRDC discharge = 3,122 is a typo R-Hydronet gives 112 • R-Hydronet was retained for Limay @ Paso Flores 208 1600 1400 1200 1000 800 600 400 200 19 60 19 61 19 62 19 63 19 64 19 65 19 66 19 67 19 68 19 69 19 70 19 71 19 72 19 73 19 74 19 75 19 76 19 77 19 78 19 79 19 80 0 477 9450 Limay @ Paso Limay AR SA WMO # River Gauge 10114 Limay Paso Limay Lat Lon Area Area -40.52 -70.43 26,400 19,500 • • GRDC summary data span 1903–1980 R-Hydronet has 1903–1990 • four years (1965–1968) data for Limay @ Paso Limay were given incorrectly for Limay @ Paso Flores in RIV and IHD • these agree except for a typo in GRDC [Oct 1905 should be 1,228 not 1,528] • R-Hydronet is retained under ID W10114 • • • • • the drainage area remains uncertain the independent source gives 19,500 km2 the GRDC catalogue gives 26,400 km2 Fekete et al. estimate 23,205 km2 which is near the average of the two extremes the GRDC area is retained for the present Negro @ Primera Angostura WMO # RIV # River Gauge UNESCO 209 Area Fekete et al. AR SA • • • • • • 9449 506 Negro Primera Angostura 95,000 185,798 there is a large discrepancy between the drainage areas given by UNESCO and Fekete et al. the difference appears to be due to the inclusion of what may be a closed system to the south of the central Negro basin the UNESCO area is retained for the present WMO, GRDC summary data and an independent source (IND1) give 1927 – Mar 1980 the independent series is truncated or rounded down on many months, but otherwise identical to WMO/GRDC • IHD, RIV and another independent source give a coherent alternative series for 1965–1979 this series differs from WMO / IND1 over 1973–1975 by small discrepancies • R-Hydronet gives 1927–1994 • • GRDC/WMO have a typo Jul 1937 is 1,604 not 1,064 m3/s • • • R-Hydronet was retained with 1972 with the caveat that 1972 may be in error the annual average of 357 m3/s is the lowest on record for 67 years moreover, 1972 data are inconsistent with upstream and neighbouring sites [see discussion for Neuquen @ Paso de Los Indios below] Neuquen @ Paso de Los Indios WMO # RIV # River Gauge Area AR SA 9926 482 Neuquen Paso de los Indios 30,200 AR SA AR SA AR SA 9446 10114 9449 480 Colorado Limay Negro Buta Ranquil Paso Limay Primera Angostura 15,300 26,400 95,000 506 • • • • IHD / RIV have 1965–1979 an independent source [IND] has 1949–1952 and 1965–1979 GRDC has summary data for 1903 – Mar 1980 R-Hydronet has 1903–1994 • • • these agree on concurrent months except for some typos in GRDC for Jun 1929, GRDC discharge = 11 should be 141 for Jul 1947, GRDC discharge = 1,721 should be 172 210 • May–Jun, and possibly Apr and Jul–Aug of 1972 are suspect R482 1972 R-Hydro 1972 • • • • • • J F M 171 171 89 89 72 72 A M J J A S O N D mean 105 1079 1004 69 1098 990 480 489 952 963 570 578 509 515 783 790 762 772 548 550 May and Aug discharges are the highest, and the annual mean is the second highest for 91 years the annual maximum (May) follows the annual minimum (Apr) which is also unusual indicated above. of neighbouring gauges, Neuquen @ Paso de Los Indios should be most similar to Colorado @ Buta Ranquil in the basin just to the north at Colorado @ Buta Ranquil, May, Jun, Aug and the annual average are above normal but well below the respective maxima for 40 years of record the next nearest gauge to Neuquen @ Paso de Los Indios is Limay @ Paso Limay to the south the 1972 annual mean for Limay @ Paso Limay was above normal, but well below the maximum for 78 years of record, and Aug was the wettest month of the year • in 1972, the downstream gauge at Negro @ Primera Angostura, which is below the confluence of the Rio Neuquen and Rio Limay, 1972 is the driest year on record • if 1972 data for Neuquen @ Paso de Los Indios are valid, there a strong reasons to believe that 1972 data for Negro @ Primera Angostura are in error • conversely, if 1972 data for Negro @ Primera Angostura are valid, there a strong reasons to believe that 1972 data for Neuquen @ Paso de Los Indios are likely in error • returning to Neuquen @ Paso de Los Indios, the best that can be made of the situation is that Aug is high but consistent with neighbouring basins, but May–Jun discharges may be in error • R-Hydronet data are retained with the caveat that May–Jun 1972 may be too high Parana @ Corrientes WMO # RIV # AR SA 10113 960 River Gauge Parana Corrientes Lat Lon -27.46 -58.85 El m a 42 b 211 Area 2 km Discharge 3 km 2,300,000 2,119,505 534 AR SA 9368 Parana Corrientes (MOSP) -27.96 -58.85 c 42 d 1,950,000 2,125,000 498 a RIV incorrectly gave this as 420 m; if the elevation for Corrientes is truly 42 m, the datum for Corrientes (MOSP) must be < 42 m. b average of estimates due to OAS and Fekete et al. (1999) c Some sources (e.g., WMO) incorrectly give this as 60 m; however, gage elevations upstream of Corrientes above the confluence with Rio Paraguay are 46 m and higher, i.e., the elevation at Corrientes must be < 46 m. Metadata inventories give elevations for both Corrientes and Corrientes (MOSP) as 42 m. d Taken as the working estimate for Corrientes (MOSP). By rough estimate, the increase over Corrientes would likely be ca. 5,000–10,000 km2. • there are two distinct records nominally identified as “Corrientes” A. Corrientes from IHD/RIV for 1968–1979 also found other sources that are most likely derivatives of IHD/RIV B. Corrientes (MOSP) found in WMO, R-Hydronet and other sources with records from 1904–1990 • • • the given coordinates locate Corrientes at Corrientes town on the east bank opposite Barrenqueras town which is the river port for the city of Resistencia a Rio Parana gauge inventory, in addition to Corrientes (MOSP), lists a gauge called Barrenqueras that might be the same entity as Corrientes all sources consistently place the record labelled Corrientes (MOSP) 56 km (straight line distance) downstream from Corrientes at the town of Empedrado [which raises a legitimate question of why the gauge is not named Empedrado] Dubious Drainage Areas • the drainage areas assigned to both gauges are wrong !! • • Corrientes is ca. 30 km below the confluence of Rio Paraguay with Rio Parana at the confluence, the combined drainage area is consistently estimated at 2.0–2.1 million km2 hence, the drainage area at Corrientes is at least 2 million km2, and likely greater other drainage area estimates for Corrientes are 2,067,000 km2 [OAS] and 2,172,000 km2 (Fekete et al., 1999) the average of these, 2,119,505 km2 is accepted herein • • • • if the specified location coordinates are correct, Corrientes (MOSP) has a somewhat larger drainage area than Corrientes, but the difference cannot be determined reliably without delineating the basin via high resolution maps or DEMs 212 • for a rough working estimate, Corrientes (MOSP) drainage area is taken as 2,125,000 km2 Declining Discharge in the Lower Parana • • • • • • • evidence from summaries of concurrent data for 5 gauges below the confluence of Rio Paraguay and Rio Parana suggest that Parana discharge declines ca. 10% down to Tumbes near the city of Rosario over an intervening drainage area of up to 175,000–300,000 km2 or more evidence from a Rio Parana navigation study indicates that average water velocities decrease 10+ fold below the confluence of Rio Paraguay and Rio Parana thereby increasing water residence time 5–10+ fold; hence increasing evaporation losses in the lower reach however, below Corrientes town, it is unlikely that any gauges capture all the discharge passing down the Parana or entering from local tributaries below Corrientes, the valley broadens and the river meanders in braided greater channels through swampy terrain flanked by a tangled skein of minor channels at Corrientes–Barrenqueras, the total Parana discharge could be monitored by gauges on two channels; however, below this cross-section, there appear to be no locations were gauges capture all the discharge passing down the Parana on the concurrent 12 yrs data, mean annual discharge at Corrientes is 7% higher than at Corrientes (MOSP) — see figure below as intersite drainage area between Corrientes and Corrientes (MOSP) can only be 5,000–10,000 km2, the 7% discharge loss between Corrientes and Corrientes (MOSP) is excessive, and may be passing down minor channels on the west flank of the main channel past Empedrado 35000 30000 25000 20000 15000 10000 5000 1968 1969 1970 1971 1972 1973 1974 RIV_960 213 1975 9368 1976 1977 1978 1979 • it is possible that the Corrientes record is just an alternate version of the Corrientes (MOSP) record; i.e., an early version that has since been revised, but the two records are different enough that they are just as likely to be from distinct gauges • for Oct 1919 Corrientes (MOSP), WMO/GRDC discharges of 16,900 / 17,000 are typos R-Hydronet gives 11,964 which is consistent with other gauges on the Parana • Data Retained • • for the present, the long Corrientes (MOSP) record is retained in the data file the short Corrientes record, deleted in a previous release, has been restored as it seems more likely to be a legitimate record that can be used to adjust the longer Corrientes (MOSP) record Parana @ Paso’s WMO # AR SA 9367 RIV # 513 River Gauge Parana Posadas • • • IHD / RIV / WMO identically have 1965-1979 GRDC summary data give 1901–1986 R-Hydronet gives 1901–1990 • • • the three versions all differ slightly on concurrent months, GRDC data are consistently the highest, while R-Hydronet are consistently the lowest R-Hydronet data average about 2% lower than GRDC data • the R-Hydronet record appears to be the most recent and was retained Pasaje / Juramento @ Miraflores WMO # AR SA AR SA AR SA RIV # 495 501 9444 River Gauge Juramento Pasaje Pasaje Miraflores Miraflores Miraflores 1st yr last yr 1965 1976 1929 1975 1979 1980 • Rio Juramento and Rio Pasaje are alternate names for the same river 214 • the spliced record of R495 and R501 is virtually identical to W9444 • • R-Hydronet has 1929–1986 except Mar–Aug 1980 are missing all versions of the record are concordant on concurrent months • beginning May 1978, the character of the record changes perceptibly as shown in the plot below the record has strong seasonality from 1929 through early 1978, i.e., the low flows occur in all years after May 78, instead of declining as usual, discharges begin creeping up for 3 winters (Jun-Nov) in succession, discharges are 3 fold higher than normal, and the annual discharge is 50% higher • • • • • • • independent sources have data for a downstream gauge (Pasaje @ El Tunal) that show a similar pattern from May 1978 thus, the historical regime appears to have been altered after ca. May 1978 possibly by diversion into the watershed above the Miraflores gauge, perhaps by further development of the Cabra Corral hydroelectric complex upstream of Miraflores if there has been a diversion, the effective drainage area of this gauge has changed R-Hydronet data were retained 215 RIV_495 RIV_501 m3/s 102 101 1965 1967 1969 1971 1973 1975 1977 1979 1981 Salado @ El Arenal WMO # AR SA 9445 RIV # 505 River Gauge Salado El Arenal • • • this is further down the Rio Pasaje-Juramento-Salado system in the arid climate, discharges decline appreciably below Pasaje @ Miraflores the same post-May 1978 rise in discharge level seen at Pasaje @ Miraflores is also evident at this site • • • IHD / RIV have 1965–1979 WMO and an independent source have nearly identical data for 1929–1980 R-Hydronet has 1929–1985 • there are discrepancies between WMO/R-Hydronet and IHD / RIV for the older 1960s records that appear to be errata in IHD / RIV • R-Hydronet was retained 216 Salado @ Achupallas WMO # AR SA • • • • 9371 RIV # 965 River Gauge Salado Achupallas this is on the Rio Salado system to the west and south of Buenos Aires the climate is arid and discharges are apparently erratic the available records are merely a short fragment from Feb 1976 – Apr 1979 with some missing months all records agrees except for Jan – Apr 1978 of W9371 which are the data given for Jan – Apr 1979 by the other sources (RIV and two independent versions) Salado @ H.C.Casanas WMO # AR SA 9369 RIV # 460 River Gauge Salado H.C.Casanas • essentially identical data 1968–1975 are found in IHD, RIV, WMO and R-Hydronet • this a mystery site • the location coordinates given by most sources place the gauge offshore in the middle of the Mar del Plata between Argentina and Uruguay R-Hydronet put this on the lower Pasaje-Juramento-Salado system, but the gauge might be on any of several Argentine Rio Salado’s • • • no source gives a drainage area for this gauge the gauge location “H.C.Casanas” cannot be found in readily available maps and gazetteers • these data are only useful if the correct gauge location can be determined Sali Dulce @ El Sauce (1967: Embalse Rio Hondo) — Warning: probable composite WMO # AR SA • • 9451 RIV # 497 River Gauge Sali Dulce El Sauce (1967: Embalse Rio Hondo) Embalse Rio Hondo (Rio Hondo reservoir) is located just upstream of the town Termas de Rio Hondo at the base of the Andes the reservoir receives discharges of the Sali Dulce and several smaller tributaries from the southwestern flank 217 • a reservoir fact sheet fails to give the completion data, but 1967 is suggested by the gauge name “El Sauce (1967: Embalse Rio Hondo)” • there are reasonable grounds to believe that this is a composite record from A) a place called “El Sauce” to 1966 B) Embalse Rio Hondo discharge from 1967 • mean discharge levels jump appreciably after 1967; however, 1973-1980 were abnormally wet years, so part of the increase in general climatological trend data from another gauge in R-Hydronet also suggest that “El Sauce” may have been upstream of the tributaries draining to the Rio Hondo reservoir; and the Embalse Rio Hondo outflows should be ca. 24% higher than “El Sauce” • • • • drainage areas specified for “El Sauce (1967: Embalse Rio Hondo)” range up to 2 22,070 km the selected value of 18,250 km2 is taken from the reservoir fact sheet this may be wrong, but it is consistent with other gauge metadata from R-Hydronet Available Discharge Records • • WMO, GRDC summary data, and an independent series have nearly identical data from Sep 1926 – Apr 1980 for 1978–1980, these series are missing scattered months • • • IHD and RIV have fragments for Jan 1965 – Aug 1972 and 1976–1979 these are mostly similar to WMO/GRDC but differ on scattered months some months are missing; these may have been provisional data • R-Hydronet gives Sep 1925 – Aug 1980, but has numerous missing months from 1968 onward • to 1968, R-Hydronet, GRDC, WMO and an independent version agree except for the following typos in GRDC/WMO Apr 1934 GRDC/WMO discharge should be 199 not 1999 m3/s Nov 1947 GRDC/WMO discharge should be 38.4 not 328 m3/s • • • from 1967–1980, there are three different versions of the record a) R-Hydronet b) WMO/GRDC c) IHD/RIV • from Jan 1967 – Jul 1972 differences are small, more likely to due different versions of the same record compounded with a few typos regulation of the discharges by the dam is clearly evident • 218 • from Aug 1972, WMO/GRDC and IHD/RIV are more similar to each other than to RHydronet • • • R-Hydronet has regulated discharges WMO/GRDC/RIV have unregulated discharges WMO/GRDC/RIV unregulated discharges could be a) net inflows calculated from regulated discharges and changes in reservoir storage b) the sum of gauged inflows from Rio Sali Dulce and several tributaries draining directly to the reservoir from 1974–1980, regulated and unregulated discharges balance within 3% suggesting that the WMO/GRDC/RIV data are calculated from reservoir outflow and storage data • Data Retained • • • the record retained is a composite of the following: R-Hydronet data Dec 1967 which are free of typos present in WMO/GRDC a WMO/RIV composite from 1968–1980, constructed by filling some missing months of 1978–1979 in WMO with data from RIV • this series should be re-retrieved from the source agency if the opportunity arises • R-Hydronet data are for 1968–1980 are listed below for anyone who wants to substitute them the two red-shaded months may be typos • 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 J F M A M J J A S O N D 52.6 42.1 36.6 62.9 11.8 152.0 68.1 183.0 134.0 530.0 262.0 192.0 127.0 20.5 6.8 5.7 264.0 51.4 282.0 301.0 434.0 - 68.8 139.0 35.4 123.0 457.0 227.0 370.0 473.0 245.0 443.0 - 160.0 39.1 147.0 229.0 273.0 160.0 397.0 328.0 409.0 160.0 121.0 39.9 124.0 109.0 69.5 99.0 199.0 106.0 140.0 67.3 61.9 7.4 67.1 68.6 70.4 93.2 97.2 129.0 81.3 103.0 49.5 68.3 45.8 39.0 52.0 77.2 74.6 76.6 129.0 105.0 71.2 81.5 69.9 58.9 73.4 96.5 59.0 87.1 96.9 128.0 125.0 61.0 74.0 70.6 32.3 23.6 62.5 97.8 93.4 115.0 132.0 127.0 - 62.4 58.7 65.2 18.2 56.4 96.7 134.0 125.0 97.4 - 95.3 53.7 58.7 26.7 65.3 131.0 98.0 130.0 65.5 - 170.0 62.6 55.5 10.7 77.7 217.0 61.1 200.0 59.5 - 219 San Juan @ La Puntilla/Dique I. de la Rosa WMO # AR SA • • 9447 RIV # 485 River Gauge San Juan La Puntilla • WMO & GRDC spans 1907–1980 R-Hydronet has 1907–1989 under the gauge name “Dique I. de la Rosa” at the same coordinates IHD, RIV, and an independent series have shorter series • • the drainage area usually given for this record (25,000 km2) is likely too low it has been replaced with an alternate estimate of 26,356 km2 due to Fekete et al. • • for Jun 1967, WMO/GRDC discharge = 99.4 is a typo the other sources give 29.4 • • for Jan 1972, WMO/GRDC discharge = 3.7 is a typo the other sources give 33.7 • • for Jun 1972, IHD / R485 discharge = 2.0 is a typo the other sources give 16.2 • R-Hydronet was retained Tercero @ Embalse Ministro Juan Pistarini WMO # AR SA • • • • 9452 RIV # 500 River Gauge Tercero Embalse Ministro Juan Pistarini according to Argentinean sources, Rio Tercero begins as the outflow of Tercero I reservoir which was constructed in 1936 the lower reach to the confluence with the Parana appears to be known as the Carcana or Carcaraña Embalse Ministro Juan Pistarini given as the gauge location in one source may be the official name of the Embalse Tercero or Tercero I commonly shown on many maps (embalse = reservoir) there is also a smaller “equalizing” dam/reservoir below the main Tercero Reservoir • this record in WMO was identified only as unknown @ unknown with no geo coordinates or drainage area • • • IHD / RIV give 1968–1979 WMO gives 1913–1980 R-Hydronet gives 1913–1984 220 • except for a few typos and 1973–1975, these records are identical • three sizable discrepancies between the R-Hydronet and WMO/RIV versions are listed below the Mar 1978 WMO/RIV discharge is most likely a typo for the other two discrepancies, either alternatives are plausible • • R-Hydronet WMO/RIV dif 3.9 30.5 76.3 39.0 90.5 176.0 -35.1 -60.0 -99.7 1913 11 1939 12 1978 3 RIV_500 WMO_9452 m3/s 102 101 100 1968 • 1970 1972 1974 1976 1978 1980 the figure above shows two things: a) Rio Tercero outflows generally appear to be unregulated; these are likely reservoir outflows adjusted by changes in reservoir storage, or the effective net inflows to the reservoir b) R500 data for 1973–75 are regulated outflows • the R-Hydronet record is retained • the 1973-75 R500 record fragment is included below for anyone that wants it J F M A M J J A 221 S O N D 1973 1974 1975 30.0 21.5 20.0 29.5 14.0 29.0 96.0 13.5 33.0 55.0 22.5 29.0 34.5 22.5 28.0 32.0 20.5 25.5 32.5 20.0 20.0 31.5 25.5 18.0 31.0 20.0 18.5 30.0 17.0 29.0 26.5 20.0 29.0 22.5 17.5 26.5 Lat Lon El m Area km2 -31.38 -31.40 -57.98 -58.03 6 2 244,000 249,312 South America: Argentina / Uruguay Uruguay @ Salto and Uruguay @ Concordia WMO # SA UY SA AR • • 9431 9370 RIV # 511 River Gauge Uruguay Uruguay Salto Concordia Salto and Concordia are directly opposite each other at the same latitude on the Uruguay River the dam creating the large Salto Grande reservoir, located 5-10 km upstream of the two cities, was completed in 1979 • these two discharge records end in 1979 • • the metadata may be off slightly the Uruguayan “Salto” gauge appears to have been located somewhere upstream of the two cities, likely near the current dam site the Argentine “Concordia” gauge appears to have been at or just downstream of the two cities drainage areas are given variably in different sources, but there would not be enough intervening drainage between the two gauges have an appreciable affect on discharges, i.e., the two records could be safely averaged to produce a composite • • South America: Bolivia Beni @ Angosto del Bala WMO # BO SA 9372 RIV # 962 River Gauge EL m El m Beni Angosto del Bala 284 644 • • • UNESCO records have 1976-1979 more recent data spanning 1967-1990 are available from www.lba-hydronet.sr.unh.edu/ for the concurrent 4 yrs, UNESCO records have perceptibly higher discharges • for the present, the lba-hydronet data are retained 222 • • • • if UNESCO data are substituted for 1976-1979 in the lba-hydronet record, the long term mean annual discharge is 70.5 km3 rather than 69.2 km3 gives a gauge datum of 644 m versus 284 m given by UNESCO the lba-hydronet datum is inconsistent with other Rio Beni metadata in the the lbahydronet set hence, the UNESCO datum appears to be more reasonable and is retained lba-hydronet Desaguadero @ Ulloma WMO # BO SA RIV # 9375 964 River Gauge Desaguadero Ulloma Area Discharge km2 km3 1,802 100,802 2.44 2.44 Runoff mm 1,355 24 • the drainage area for this gauge is wrong • • the Desaguadero drains Lake Titicaca at the oulet, the Titicaca basin has an area of ca. 56,000 km2 and the Desaguadero has long term mean annual specific runoff of ca. 20 mm • • • at Ulloma, the Desaguadero catchment is ca. 100,000 km2 for the Ulloma gauge, the drainage area was corrected as above the long term mean annual discharge for Ulloma is ca. 2.4 km3, almost identical to the four yrs (1976-1977) mean discharge for the available record Grande @ Abapó BO SA • • • • • • • • • WMO # RIV # River Gauge 9377 1138 Grande Abapó EL m El m 500 430 UNESCO records have 1976-1979 more recent data spanning 1976-1990 are available from www.lba-hydronet.sr.unh.edu/ lba-hydronet data are riddled with missing entries including much of 1976-1979 concurrent lba-hydronet and UNESCO data differ somewhat both lba-hydronet and UNESCO data may be poor in quality discharges are given below 1979 is missing it is unclear why so many discharges from 1976-1979 are missing the nominally more recent lba-hydronet data it is possible that the old UNESCO data were derived using liberal rules from primary gauging data with numerous missing days lba-hydronet 223 • despite differences in monthly records, the manner in which lba-hydronet and UNESCO data are combined has only small effects on annual and seasonal summary statististics J F M A M J J A S O N D mean 1976 - - - - - - - - - - 67 116 91 1977 238 464 185 - 117 56 41 39 45 65 203 361 165 1978 - - - - 130 75 53 42 38 34 165 456 124 • • • • for the present, a composite record comprising the 1976-1979 UNESCO record and 1980-1990 lba-hydronet data is retained gives a gauge datum of 430 m versus 500 m given by UNESCO it is unclear which is more correct the UNESCO datum is retained for the present lba-hydronet South America: Brazil On-line data now available • the Brazilian agency ANEEL [Agência Nacional de Energia Elétrica] now makes it’s hydrometric data base [rainfall, water level and stream discharge] available at hidroweb.aneel.gov.br/ • • ANEEL has data collected by ANEEL for it’s mandate to operate hydroelectric facilities ANEEL also has many other records for gauges operated by other federal and state agencies, but is not a complete archive of all stream discharge data collected in Brazil • ANEEL metadata have scattered errors in gauge coordinates, drainage areas and elevations, though the gross percentage of errata is likely small • ANEEL has records for 12 of 14 Brazilian gauges in the UNESCO files listed below with the ANEEL code need for retrieving data, and the gauge names as given in the ANEEL site catalogue BR BR BR BR BR SA SA SA SA SA WMO # ANEEL # River Gauge 9380 9381 9386 9387 9389 64843000 48020000 18850000 22350000 27500000 Parana Sao Francisco Xingu Tocantins Araguaia Guaira (Porto Guaira) Juazeiro (Pcd) Altamira Porto Nacional (Pcd) Conceição do Araguaia (Pcd) 224 BR SA BR SA 9390 9391 29200000 49660000 Tocantins Sao Francisco Itupiranga Traipu BR SA 9379 17050000 Amazon Obidos (Pcd) BR SA BR SA 9382 9385 58974000 15400000 Paraiba do Sul Madeira Campos-Ponte Municipal Porto Velho BR SA 9383 65895002 Iguaçu (Iguazu) Salto Osorio-Jusante Uhe BR SA 9388 34880000 Parnaiba Porto Formoso BR SA BR SA 9378 9384 54780000 67050000 Jequitinhonha Paraguai Jacinto Fecho dos Morros • comparison of current ANEEL versions of records with concurrent UNESCO data reveals that some records have seen significant retrospective revision, and that the UNESCO records contain scattered errata; hence, all concurrent records were replaced with current ANEEL data • UNESCO data for the first 7 gauges (yellow shading) were completely replaced by longer ANEEL data • the Amazon @ Obidos gauge record was also replaced by the current ANEEL data — see the section on Amazon @ Obidos for more details • for two gauges [Paraiba do Sul @ Campos-Ponte Municipal; Madeira @ Porto Velho], UNESCO records have some early data not presently available in the ANEEL archive; the old data were composited with the ANEEL records • for the gauge Iguaçu (Iguazu) @ Salto Osorio-Jusante Uhe, ANEEL has only recent post-1985 data; hence, the present record is a composite of older UNESCO data [1941-1975] and 1985–1995 ANEEL data • for the gauge Parnaiba @ Porto Formoso, the present record is a composite of the now defunct Porto Formoso gauge with the new Luzilandia gauge; see the separate section on Parnaiba @ Porto Formoso / Luzilandia • two gauges [Jequitinhonha @ Jacinto; Paraguai @ Fecho dos Morros] presently have no data in the ANEEL archive; hence, UNESCO records are retained as is Amazon @ Obidos WMO # BR SA • • 9379 RIV # 514 River Gauge Amazon Obidos ANEEL gives a record from 1928 to early 1998 excluding missing years and months this is the most recent “official” version of the Amazon @ Obidos record 225 • UNESCO files span 1928–1983, but are missing a large block (Oct 1947– Feb 1969), Jan 1970–Feb 1971, and 1979 • • for Feb 1947, W9379 discharge = 14,400 is a typo the other sources give 144,000 • • GRDC annual summary data give 1928–1947 and 1968–1996 these are likely a version of the record released by ANEEL in 1997 or so Warning: multiple versions & dubious records for Amazon @ Obidos • this data set gives the ANEEL version of the Obidos record available in late 2000 • • Obidos is the most downstream gauge on the Amazon River the record for Amazon @ Obidos has undergone [and may continue to undergo] appreciable revision from one release to the next at least three versions ultimately attributable to Brazilian authorities are currently in circulation the differences in estimated mean annual runoff and apparent time trends exhibited by these alternatives are significant • • • • except for some fragments, the period 1948–1969 was mostly ungauged one informal version which has the missing periods filled with estimates of unknown reliability has come into informal circulation — there may be others • ANEEL should be consulted for the latest “official” version • alternate versions of the Obidos record appear to represent ongoing attempts to correct older data that are likely too low • as per the figure below, the old UNESCO record [released in the 1980s] gives low discharges for the early period (1928-1947); higher [but still evidently low in the eyes of the authorities] discharges from 1969–1970; and discharges for the early 1980s that are only marginally lower than the current official version • the record released by GRDC in 1999 [likely released by ANEEL in 1997 or 1998] has very high discharges for the historical periods 1928-1947 and 1970–1979 • the current ANEEL version [likely released in 1999 or 2000] estimates the early period discharges as roughly midway between the UNESCO version and the GRDC_99 version 226 210,000 Amazon @ Obidos; mean annual discharge cms 190,000 170,000 150,000 130,000 1928 1932 1936 1940 1944 1948 1972 UNESCO 1976 ANEEL 1980 period 3 km 1992 1996 Annual specific runoff change 3 1988 GRDC_99 Annual discharge volume UNESCO GRDC_99 1984 km UNESCO GRDC_99 change 3 mm mm mm yrs yrs km 1928-1947 19.8 19.8 4,732 5,776 1,044 1,020 1,245 225 1969-1983 12.6 13.8 5,162 5,487 325 1,113 1,183 70 1928-1983 32.3 33.6 4,899 5,657 758 1,056 1,219 163 Potential Problem: 1968–1969 • • • UNESCO and GRDC give Mar–Dec 1969 that are not in the current ANEEL release the current ANEEL release gives Mar–Dec 1968 it is possible that the current ANEEL data for 1968 actually belong to 1969 J F 1968 - - 150,906 165,955 196,631 195,047 171,107 152,973 141,403 133,915 125,984 126,603 UNESCO 1969 - - 154,800 176,500 204,200 203,100 182,600 158,000 136,300 123,700 113,600 114,400 ANEEL M A M J 227 J A S O N D Jequitinhonha @ Jacinto BR SA WMO # RIV # River Gauge 9378 Jequitinhonha Jacinto 520 • IHD, WMO, RIV and an independent set (IND) have almost identical data from 1943–1978 • • • • there is an error in Nov 1969 in the two series RIV and IND give 144 WMO and IHD give 444 WMO/IHD are likely correct; Nov discharges rose from the Oct level at the neighbouring Sao Francisco River with the onset of the wet season; the RIV/IND discharge of 144 would be a decline from the Oct 1969 discharge of the Jequitinhonha W9378 is retained • Parnaiba @ Porto Formoso / Luzilandia composite WMO # RIV # BR SA 9388 1146 River Gauge Parnaiba Porto Formoso • • • the record herein is a composite of gauge records for Porto Famoso and Luzilandia the gauge was evidently moved from Porto Famoso to Luzilandia at the end of 1981 this record is accepted as a composite because the two gauge sites are virtually co-located and the distinct records can be easily separated if desired • ANEEL metadata are given below ANEEL # River Gauge 34880000 34879500 Parnaiba Parnaiba Porto Formoso Luzilandia Lat Lon el m area 2 km discharge 3 km -3.45 -42.37 -3.45 -42.37 20 26 282,000 322,800 25.1 24.0 1st yr last yr 1963 1982 1981 1998 • • • Luzilandia is a few km downstream of Porto Famoso ANEEL coordinates place the two gauge at virtually the same location mean annual discharge volume is almost identical for the two gauges • • • gauge elevations should be nearly identical Luzilandia elevation should be slightly lower than Porto Formoso the average of ANEEL metadata (23 m) is accepted for the present • the ANEEL drainage area for Luzilandia is wrong [ANEEL also gives the total Parnaiba drainage area as 325,000 km2 ] 228 • • • the drainage area for Luzilandia should be slightly (<1%) greater than Porto Formoso for the present, the gauge area for Porto Formoso (282,000 km2) is accepted drainage area should be determined from a high resolution DEM if available South America: Chile Bio Bio @ Desembocadura WMO # CL SA 9394 RIV # 451 River Gauge Bio Bio Desembocadura • • UNESCO sources have data for 1966–1972, and 1980–1984 an independent source (IND) has data for Sep 1963 – May 1992 with some scattered missing months • • for Feb 1982, W9394 discharge = 219 is likely a typo the other sources give 249 • IND was retained for 1963– 1992 with some unrounded months taken from R451 Baker @ La Colonia WMO # CL SA • • 9395 RIV # River Gauge 444 Baker La Colonia UNESCO sources have 1966–1969 and 1980–1984 an independent set with data from 1963–1984 was retained with some unrounded months taken from R444 Limari @ Panamericana WMO # CL SA • • 9396 RIV # 441 River Gauge Limari Panamericana UNESCO sources have 1966–1972 and 1980–1984 an independent set (IND) with data from Oct 1958 – Apr 1992 was retained with some unrounded months taken from R441 229 • • for Aug 1981, W9394 discharge = 0.3 is likely a typo the other sources give 3.6 • beyond years given in UNESCO, IND could not be corroborated independently at present these data should be used with caution • • • except for two months listed as missing, Jan 1960 – Feb 1961 are all 0s this site is on the southern fringe of the Chilean northern desert, so these may be legitimate data Maipo @ Cabimbao WMO # CL SA RIV # 9392 440 River Gauge Maipo Cabimbao • • Mar 1969 discharge = 15 in W9392 is likely a typo R440, IHD and an independent source give 5 • • • Dec 1980 discharge = 138 in W9392 is likely a typo R440 and an independent source give 238 the discharge pattern at the neighbouring Rapel @ Corneche gauge supports 238 Rapel @ Corneche WMO # CL SA 9393 RIV # River Gauge 443 Rapel Corneche • • UNESCO sources have data from 1966–1979 data were added from an independent source for 1917–1982 • • 1968 data in all sources are identically the lowest on record by a large margin this site is very close to Maipo @ Cabimbao which for 1968–1970 had low, nearly identical discharges if this pattern held for Rapel @ Corneche, the 1968 mean annual discharge would have been ca. 1,000 m3/s not 445 m3/s it is possible that 1968 data are for another locale, either upstream on the Rapel or in another watershed • • South America: Colombia 230 Atrato @ Tagachi CO SA • • • WMO # RIV # River Gauge 9403 1148 Atrato Tagachi UNESCO sources have 1976–1979 an independent set (IND) has 1966–1990 IND is retained with some unrounded months taken from W9403 Cauca @ La Pintada CO SA WMO # RIV # River Gauge 9399 1341 Cauca La Pintada • • UNESCO sources have 1969–1972 and 1980–1984 an independent set (IND) has 1969–1990 • • for Feb 1972, R1341 discharge = 1,046 is likely a typo the other sources give 1,064 • • for Nov 1980, R1341 discharge = 57 is likely a typo the other sources give 547 • IND is retained with some unrounded months from W9399 Magdalena @ Calamar CO SA • • • WMO # RIV # River Gauge 9400 1047 Magdalena Calamar UNESCO sources have 1971–1979 an independent set has 1971–1990 IND was retained with some unrounded months taken from W9400 Magdalena @ Puente Santander CO SA • • WMO # RIV # River Gauge 9407 1124 Magdalena Puente Santander for Jul 1971, R1124 discharge = 232 is likely a typo the other sources give 323 Meta @ Puente Lleras 231 CO SA WMO # RIV # River Gauge 9454 1338 Meta Pte Lleras • • for Nov 1981, W9454 discharge = 300 may be a typo the other sources give 388 • • for Jul 1982, W9454 discharge = 987 may be a typo the other sources give 981 San Juan @ Penitas CO SA WMO # RIV # River Gauge 9455 1339 San Juan Penitas • • UNESCO sources have 1980–1984 an independent set (IND) has 1965–1990 with some missing months • • for Mar 1980, W9455 discharge = 1,998 is almost surely a typo the other sources give 1,098 • • for Jul 1984, W9455 discharge = 1,969 may be a typo the other sources give 1,959 • • for Oct 1984, R1399 discharge = 2,623 is likely a typo the other sources give 2,923 • IND was retained with the above corrections and a few unrounded months taken from W9455 South America: Ecuador General Remarks • • • • • available discharge data include UNESCO sources (RIV, WMO, IHD) and an independent set (IND) several discharge records are corrupted to some extent in all available sources some metadata remain uncertain many of gauge locations are designated A.J. xxx or D.J. xxx these are likely abbreviations for antes/despues (before / after) junta (junction / confluence) [con] with river xxx 232 • the independent set has data that are not in the UNESCO files, and cannot be independently corroborated but for a few sites that can be checked against rain gauge records WARNING — Drainage Area Uncertainties • • • • EC EC EC EC EC EC perceptibly different drainage areas are cited for 6 Ecuadorian gauges in WMO/RIV metadata and the GRDC catalogue these are small watersheds; specific runoff estimates will vary similarly the GRDC catalogue ostensibly has more recent figures; however, this cannot be taken as definitive the GRDC areas have been retained with the caveat that neither the location coordinates of the gauges nor the drainage areas can be reliably validated at present SA SA SA SA SA SA WMO # RIV # 10115 9413 9412 9419 9416 9411 467 466 462 449 458 463 River Gauge Zapotal Vinces Quevedo Calera Toachi Mira Lechugal Vinces Quevedo a.j. Amarillo a.j. Pilaton d.j. Lita WMO/RIV GRDC dif %dif 2,300 5,380 4,260 215 1,640 5,630 2,980 4,400 3,507 252 1,431 4,960 -680 980 753 -37 209 670 26 20 19 16 14 13 WARNING — Time-shift: Quevedo @ Quevedo / Vinces @ Vinces WMO # EC SA EC SA • • • • • 9412 9413 RIV # 462 466 River Gauge Quevedo Vinces Quevedo Vinces at these two sites, 1966–1968 data are time-shifted one month forward in UNESCO sources (specifically IHD, WMO and GRDC summary data; RIV has only data from 1969) from Jan 1969, data have the correct chronology independent source IND has the correct chronology this is confirmed by rain gauge records, and to some extent by limited discharge data at other sites Jan–Apr are the wet months with rains beginning some years in December (especially during El-Niño years) 233 • if Jan discharges to 1968 and from 1969 onwards are contrasted, the difference is obvious • • IND has the correct chronology, and data for several years not in UNESCO files IND was retained Chimbo @ Bucay WMO # EC SA RIV # 9925 469 River Gauge Chimbo Bucay Lat Lon -2.17 -79.10 • • RIV and an independent source (IND) give data for this site R469 data labelled Chimbo @ Bucay are identical to data given by WMO, RIV, IHD and IND for Quijos @ d.j.Oyacachi • IND is accepted for Chimbo @ Bucay, with the reservation that, presently, there are no independent means to check these data, other than that they are different from all other Ecuadorian discharge data • available sources also gave the wrong location coordinates (-1.17, -79.13) for Bucay which are correctly given above Quevedo @ Quevedo WMO # EC SA • • • • RIV # 9412 462 River Gauge Quevedo Quevedo there are several perceptible discrepancies between IND and UNESCO in 1969– 1970 all UNESCO sources have the same data as given 25 years ago in IHD for the present, IND was accepted arbitrarily for the present set the UNESCO data can be easily restored if desired J F M A M UNESCO 1969 IND 1969 192 278 226 226 465 506 595 656 UNESCO 1970 IND 1970 309 311 524 525 404 404 570 615 J J D mean 327 328 284 130.0 57.5 44.0 31.5 31.0 88.0 286 130.0 57.2 44.1 31.4 30.7 87.6 206 222 430 449 169 77.0 49.0 36.5 32.0 30.0 46.0 168 75.3 48.8 36.5 31.9 29.7 52.3 223 229 234 A S O N Zapotal @ Lechugal WMO # EC SA 10115 RIV # 467 River Gauge Zapotal Lechugal • RIV and an independent source (IND) give data for this site, but R467 gives data (1969-1972) that are identically given for Quevedo @ Quevedo by RIV, WMO, IHD and IND • • • IND spans 1964–1974 GRDC summary data span 1964–1994 these agree on concurrent months except for what are most likely errata in GRDC • • • in Dec 1969, GRDC discharge = 5 IND gives 15.5 discharges at neighbouring sites (Quevedo @ Quevedo, Vinces @ Vinces) rose from Nov to Dec, and this site should follow a similar pattern which supports IND over GRDC • • • in Feb 1970, GRDC discharge = 50 IND gives 406 this is a high discharge month and discharges at neighbouring sites (Quevedo @ Quevedo, Vinces @ Vinces) were comparably high • • • for Mar 1970. GRDC gives 545 while IND gives 492 it is unclear which is more correct IND is retained • IND was accepted and saved under ID W10115 with two months in 1972 added from GRDC • coordinates for this site may be somewhat off, i.e., the town of Lechugal appears to be on the Vinces River, but the Zapotal may be a tributary that enters the Vinces near by South America: Guyana Essequibo @ Plantain Island WMO # GY SA • • 9360 RIV # 509 River Gauge Essequibo Plantain Island W9360 and an independent source give Jun 1978 as 3,420, while R509 gives 4,320 W9360 is accepted for the time being 235 Cuyuni @ Kamaria Falls GY SA • • WMO # RIV # River Gauge 9361 1153 Cuyuni Kamaria Falls in W936, Sep 1979 is a typo the discharge should be 1,310 as in R1153, not 13,100 as in W936 South America: Peru • • • Peruvian discharge data are collected by the agency known as SENAMHI [Servicio Nacional de Meteorología e Hidrología] the SENAMHI www site [www.senamhi.gob.pe] gives some limited information on Peruvian discharge gauges SENAMHI has not always consistently named gauge locations, i.e., essentially the same gauge locations have appeared on different maps with different names Majes (Camaná) @ Huatiapa PE SA • • • WMO # RIV # River Gauge Lat 9429 Majes (Camaná) Huatiapa Lon Area -15.97 -72.47 13,700 this river is known variably as the Majes, Camaná, or Camaná–Majes the drainage area should be re-calculated — the drainage area of 13,700 km2 is a crude estimate the total basin area is 17,141 km2 according to SENAMHI Ramis @ Pte Saman (Pte Carretera) PE SA WMO # RIV # River Gauge 9427 Ramis Pte Saman (Pte Carretera) 1447 Lat Lon -15.28 70.02 Area El 14,700 3,820 • • • Río Ramis is the main tributary of Lake Titicaca all UNESCO & other non-Peruvian sources give bad coordinates for this gauge locally [in the Lake Titicaca area], the gauge is called Pte Saman, and has also been identified on SENAMHI maps as Pte Ramis and Pte Carretera [road bridge] • the drainage area should be re-calculated — the drainage area of 14,700 km2 may be for the entire basin rather than the Pte Saman gauge an OAS report gives the total area of the Ramis basin as 14,859 km2 • 236 • the long term mean annual discharge for Río Ramis is 2.40 km3; however, it is unclear whether this is for the entire basin or the Pte Saman gauge Santa @ Pte Carretera PE SA • • • • WMO # RIV # River Gauge 9426 Santa Pte Carretera 1444 Lat Lon -9.00 -78.00 UNESCO has only 4 years (1965–1968) for this one PACRIM has 1936–1968 with perfect agreement on the concurrent 48 months PACRIM data were retained the available location coordinates for this one are crude and not easily refined; there are likely numerous “road bridges” (Puente Carretera) in the vicinity South America: Surinam Nickerie @ Stondansie SR SA • • WMO # RIV # River Gauge 9364 1118 Nickerie Stondansie UNESCO sources had data for 1973–1979 1980 was added from an independent source South America: Surinam / French Guiana Maroni (Marowijne, Lawa) @ Langa Tabbetje / Langa Tabiki GRDC # WMO # RIV # SR 3412800 9366 GF 3512400 10122 • • • • 1154 River Gauge Maroni (Marowijne, Lawa) Maroni (Marowijne, Lawa) Langa Tabbetje (Langa Tabiki) Langa Tabiki Area 63,700 60,930 Langa Tabiki is the name (likely the local Amerindian name) of two towns on opposite sides of the Maroni river which is also the border, and also the name of an island in the river in the near vicinity of the towns the Dutch name for the Surinam town is Langa Tabbetje, and the river is known as Marowijne Lawa is an alternate name for the river that may only apply to specific reaches WMO, RIV and GRDC have 1976–1979 data for a nominally Surinam gauge called Marowijne @ Langa Tabbetje 237 • • • • • GRDC also has summary data for a nominally French Guianese gauge designated Maroni @ Langa Tabiki an old independent source (IND) gives 1952–1962 for what is nominally the French gauge Maroni @ Langa Tabiki the metadata differ somewhat the location coordinates given by all sources are crude; none plot on the river; hence, the precise location of these gauges are not known (assuming that there are in fact two gauges) the difference in nominal drainage areas is likely within the margin of error associated with estimates of the same gauge location planimetered from paper maps • while annual means are nearly identical, GRDC summary data for Maroni @ Langa Tabiki do not agree as well as they might with the other records on concurrent months • relative to the nominal Surinamese record Marowijne @ Langa Tabbetje, the GRDC record appears to be shifted one month back in time, i.e., the annual peaks and lows all occur one month for the four years (1976–1979) of concurrent data these four years have an annual mean level about 10% higher than the long term GRDC annual mean • • relative to the nominal French record for 1952–1962, the GRDC the annual peaks occur one month earlier in 6 of 11 cases, and annual lows occur one month earlier in 5 of 11 cases • dated UNESCO and IND records may explain the differences Data Retained • • the 1976–1979 UNESCO record Marowijne @ Langa Tabbetje is retained “as is” the 1952–1962 IND record Maroni @ Langa Tabiki is retained • these two can be spliced to give a combined record of 14.7 net yrs with an annual mean close to the long term GRDC annual mean South America: Uruguay Negro @ Paso Pereira 238 UY SA • • • WMO # RIV # River Gauge 9456 1342 Negro Paso Pereira UNESCO sources had data for only 1980–1984 19 years data were added from an independent source (1965–1979, 1986–1988) discharges at this site are highly irregular South America: Venezuela Apure @ San Fernando de Apure WMO # VE SA • • • 9432 RIV # 489 River Gauge Apure San Fernando de Apure WMO and RIV have only 1973–1975 an independent source gives 1962–1991 the independent data are retained with the warning that these cannot presently be corroborated beyond 1973–1975 Bocono @ Pena Larga WMO # VE SA 9435 RIV # 478 River Gauge Bocono Pena Larga • • • • WMO and RIV have only 1973–1975 an independent source gives 1953–1969, and 1973–1975 there are presently no means to corroborate the 1953–1969 data 1973 and 1974 are the two highest years on record in the joint set • • in R478, Oct 1975 discharge = 9 is likely a typo the others give 93 • • the joint WMO / IND series is retained 1953–1969 data should be used with caution • • the coordinates for this site place it too close to the Masparro River the gauge is likely further to the east Escalante @ Laferreira VE SA • WMO # RIV # River Gauge 9436 1132 Escalante Laferreira WMO and RIV have only 1973–1975 239 • • an independent source gives Apr 1962 – Mar 1968, and 1973–1975 the independent data are retained with the warning that these cannot presently be corroborated beyond 1973–1975 • no source gives a drainage area for this gauge, and the location coordinates are only crudely given Rio Escalante discharges into the southwestern corner of Lake Maracaibo a place called “Laferreira” cannot be found in any readily available sources the assigned coordinates are in the upper reaches of the Escalante; the true gauge location may be further downstream (north) • • • Guasare @ El Carbon VE SA WMO # RIV # River Gauge 9437 1133 Guasare El Carbon • • • WMO and RIV have only 1973–1975 an independent source gives Apr 1962 – Mar 1968, and 1973–1975 the independent data are retained with the warning that these cannot presently be corroborated beyond 1973–1975 • no source gives a drainage area for this site, but more precise location coordinates were found for “El Carbon” Masparro @ Pte Masparro VE SA • • • • WMO # RIV # River Gauge 9438 1134 Masparro Pte Masparro no source gives a drainage area for this gauge the location coordinates are bad there are at least 4 places along the Masparro River called Masparro the site was assigned to the upper reaches because of the low discharge; the true location may be further downstream Orinoco @ Laja de Musiu Ignacio (Musinacio ?) VE SA • • WMO # RIV # River Gauge 9440 1136 Orinoco Laja de Musiu Ignacio (Musinacio ?) WMO and RIV have only 1973–1975 an independent source (IND) gives May 1969 – Dec 1992 240 • the independent data are retained with the warning that these cannot presently be corroborated beyond 1973–1975 • • the formal place name for the gauge location is Laja de Musiu Ignacio it’s unclear if Musinacio is an error or an informal local name • • • • • Mar 1974 discharge is uncertain RIV gives 6,051 WMO gives 6,501 IND gives 6,510 currently using the WMO discharge of 6,501 Orinoco @ Ciudad Bolivar (Angostura) / Puente Angostura WMO # RIV # VE SA VE SA • • 9927 9910 503 River Gauge Lat Orinoco Ciudad Bolivar (Angostura) Orinoco Puente Angostura Lon 8.13 -63.55 8.15 -63.60 El Area 43 850,000 — 836,000 according to geographic information sources, Ciudad Bolivar is the modern name for Angostura UNESCO files have only 1923 for Ciudad Bolivar in RIV, and nothing in WMO • independent sources have two distinct records for gauges nominally designated Ciudad Bolivar and Puente Angostura • circumstances are confusing because the nominal downstream gauge, Ciudad Bolivar, has somewhat lower discharges than the nominal upstream gauge, Puente Angostura (the bridge is upstream of the city, but it is not clear that the bridge existed in 1923) Ciudad Bolivar spans 1923–1963, while Puente Angostura spans 1923-1989 possibly Ciudad Bolivar and Puente Angostura are the same gauge, but Puente Angostura represents a post-1963 retrospective revision of the historical record given in Ciudad Bolivar an unsubstantiated comment in one file suggested that Ciudad Bolivar may be a pseudo record • • • • as circumstances are unclear, both records were preserved as is and assigned unused numbers in the 9000 series • Ciudad Bolivar has lower mean annual discharge (794 km3) versus 984 km3 for Puente Angostura, a difference of 190 km3 furthermore, low discharges are higher at Ciudad Bolivar and high discharges are lower • 241 Neveri @ La Corcovada VE SA WMO # RIV # River Gauge 9439 1135 Neveri La Corcovada • WMO, RIV and an independent source have only 1973–1975 • • in W9439, Apr 1973 discharge = 70 is likely a typo the others give 7 Tocuyo @ Puente Torres WMO # VE SA • • • 9441 RIV # 479 River Gauge Tocuyo Puente Torres WMO and RIV have only 1973–1975 an independent source has 1943–1989 the independent data are retained with the warning that these cannot presently be corroborated beyond 1973–1975 Tuy @ El Clavo (El Vigia ?) WMO # VE SA • 9442 RIV # 491 River Gauge Tuy El Clavo (El Vigia ?) • • this record has been identified as Tuy @ El Vigia and Tuy @ El Clavo in different sources a place called El Clavo does exist near the given location coordinates no El Vigia could be found in the vicinity, but one may exist • WMO and RIV have only 1973–1975 Uribante Pte @ Puente Uribante VE SA • • • WMO # RIV # River Gauge 9443 1137 Uribante Pte Uribante WMO and RIV have only 1973–1975 an independent source gives Apr 1962 – Mar 1968, and 1973–1975 the independent data are retained with the warning that these cannot presently be corroborated beyond 1973–1975 242 16.0 US Data 16.1 US data sources The US Geological Survey [USGS] is the lead stream monitoring agency in the USA, but many gauges, including many in this set, are operated by other agencies such as the US Army Corps of Engineers [USACE]. The USGS maintains a national archive that contains USGS data and records for many gauges operated by other agencies. Data supplied by other agencies may not be updated regularly, and some gauges may have significant historical data that are not available in USGS archives. For reasons unknown, data for many US rivers in the main source files (WMO and RIV) are badly muddled, and have been mostly replaced here by data obtained from direct USGS sources. The records for most US sites have been updated from: 1. for most sites, the USGS NWIS-W archive [waterdata.usgs.gov/nwis-w/US/ ] 2. for five sites, the on-line US–Mexico International Boundary Water Commission [IBWC] www site (US and Mexican data for Rio Grande and Colorado River basins) [www.ibwc.state.gov/] 3. for two lower Mississippi sites, the US Army Corps of Engineers [www.mvn.usace.army.mil/eng/edhd/Wcontrol/discharge.htm] N.B. In late 2000 – early 2001, the USGS was testing a new on-line data retrieval system that could not be entered from the main page, but was accessible via some state pages or water.usgs.gov/usa/nwis/sw. This appeared to be a parallel system that sometimes gave data not available on the existing retrieval pages, and in some cases, gave site metadata that differed from those obtained via the main retrieval pages. Some sites that have not been updated or for which data are unavailable at the above sources, still have some data from the following two sources: 4. the USGS HCDN [Hydro-Climatic Data Network] CD-ROM with data for about 1,659 US gauges to 1988 [wwwrvares.er.usgs.gov/hcdn_cdrom/1st_page.html] 5. 1995 Russia-America exchange data set monthly discharges for about 455 US gauges to 1994/95 [also referred to sometimes as US96 and available via NCAR www.scd.ucar.edu/dss/datasets/ds550.1.html] In addition to new data obtained since the UNESCO files were compiled, historical records have been revised at many of the 93 US sites in the present set. Most 243 revisions are practically minuscule. Some records have seen significant retrospective revisions of old data. Some US data for Mexican border area gauges are currently (December 2000) only available from the IBWC. For reasons unknown, these have disappeared from the USGS archive. Likewise, data for some sites in the lower Mississippi basin have disappeared from the USGS NWIS archive, but are available from the USACE or the US-Russia exchange data set. A. Metadata Metadata for all US sites were revised from on-line sources. Metadata in UNESCO files have numerous discrepancies. There are also scattered discrepancies in the HCDN and US-Russia exchange data set. B. USGS Gauge Codes • USGS gauge codes for 92 official US gauges in the present set are listed in the companion spreadsheet 16.2 Unofficial US Data in UNESCO and other sources not available from USGS Some US records in WMO, RIV and other sources have longer time series than are available from the main national sources. Generally, these are records in the archives of other agencies such as the USACE, and state offices of the USGS that have not found their way into the national USGS archive. However, some of these additional data not in the national archives have appeared in US submissions to UNESCO and other compilations. As long historical records are of special interest, US data were replaced from direct USGS sources, and then overlaid with extra data from UNESCO and other sources. Twenty sites with extra data are listed below. The additional data are mainly early records. At some sites [Pend Oreille @ Newport, Ouachita @ Monroe], the extra data fill more recent gaps in the data series. For sites in the Mississippi and Red River of the North basins [yellow-shaded], the gauges are also listed in USACE archives which have metadata indicating that these gauges often began operations decades before the earliest data available from the USGS national archives. Table. Sites with extra data from unofficial sources ID# 9553 USGS# 6934500 River Gauge Missouri Hermann, MO 244 Months Net yrs 372 31.0 9586 9610 9556 9616 9551 9605 9561 9598 9557 9613 9599 9535 9617 9597 9559 9547 9562 9569 9581 9538 5082500 9521000 9380000 12395500 5587500 8162000 13343500 7289000 8459000 11303500 7367000 1034500 12399500 7245000 11530500 3611500 14191000 1059000 3438220 2131000 Red R of the North Colorado Colorado Pend Oreille Mississippi Colorado Snake Mississippi Rio Grande San Joaquin Ouachita Penobscot Columbia Canadian Klamath Ohio Willamette Androscoggin Cumberland Pee Dee Grand Forks, ND Yuma, AZ Lees Ferry, AZ Newport, ID Alton, IL Wharton, TX nr Clarkston, WA Vicksburg, MS Laredo, TX nr Vernalis, CA Monroe, LA West Enfield, ME International Boundary, WA nr Whitefield, OK nr Klamath, CA Metropolis, IL Salem, OR nr Auburn, ME nr Grand Rivers, KY Peedee, SC Total 261 132 129 129 86 77 70 45 36 35 27 9 5 3 3 3 3 2 1 1 21.8 11.0 10.8 10.8 7.2 6.4 5.8 3.8 3.0 2.9 2.3 0.8 0.4 0.3 0.3 0.3 0.3 0.2 0.1 0.1 1429 119.1 The extra data at the sites listed above were retained after consistency checks and the deletion of some suspect record fragments. 16.2.1 Caveats • • the extra data for the sites listed was compiled more than 10 years ago by 3rd parties that manually transcribed and entered data from paper hard copies; hence, typographical errata are likely present these data may have been revised [or would be revised as needs arise] by US agencies; hence, the general reliability is likely less than data from the USGS archives For anyone concerned about these unofficial data, the dates are listed in the sheet “unofficial US data” in the companion spreadsheet; so that, these data can be deleted as desired. 16.3 Drainage Areas • • metadata for some USGS gauges give both “drainage area” and “contributing area” “drainage area” appears to represent gross drainage area 245 • • • • “contributing area” is not formally defined anywhere, but appears to represent effective drainage area after accounting for non-contributing internal endorheic (closed) drainage systems, and possibly, drainage areas added or excluded due to interbasin water transfers closed drainage systems do occur in the arid / semi-arid southwestern US the known cases affecting the US sites in the present data set are listed below: positive differences indicate non-contributing internal drainage areas, while negative differences should indicated external contributing areas such as the effective drainage areas associated with inter-basin transfers ID # river gauge 9535 9570 Penobscot Merrimack 9586 Red R of the North Grand Forks, ND 9605 Colorado 9604 9609 gross contributing area area km2 km2 West Enfield, ME d/s Concord R at Lowell, MA difference % km2 16,633 12,005 17,278 11,461 -645 544 -4 5 77,959 68,117 9,842 13 Wharton, TX 108,787 79,254 29,534 27 Brazos Richmond, TX 116,568 91,792 24,776 21 Green Green River, UT 116,161 105,128 11,033 9 183,889 1,061,895 — 38,332 10,254 0 17 1 193,252 123,221 409,296 160,771 98,098 351,692 32,481 25,123 57,604 17 20 14 2,953,881 174,824 2,896,021 159,450 57,860 15,374 2 9 3,128,705 3,055,471 73,234 2 2,913,478 2,913,478 2,913,737 2,913,737 Platte / Missouri 9591 9592 9553 Platte Missouri Missouri Louisville, NE Nebraska City, NE Hermann, MO 222,221 1,072,149 1,357,672 Arkansas / Canadian 9596 9597 9554 Arkansas Canadian Arkansas Tulsa, OK nr Whitefield, OK Murray Dam nr Little Rock, AR Lower Mississippi 9598 9555 Mississippi Red Vicksburg, MS Alexandria, LA Subtotal 9600 Mississippi Tarbert Landing, MS a 10081 Mississippi Red River Landing, LA b c 10080 Atchafalaya 2,924,097 Simmesport, LA 226,805 d e Mississippi– Atchafalaya total a 241,687 3,208,700 reported as gross drainage area, but only consistent with Vicksburg if interpreted as the “contributing area”. 246 b reported as both gross drainage area and contributing area in different metadata retrievals from USGS, but only consistent with Vicksburg if interpreted as the “contributing area”. c gross drainage area estimate given in US-Russia exchange metadata; only consistent with Vicksburg if interpreted as the “contributing area”. d attributed to Simmesport in some sources, but also given as the gross drainage area for a stage recorder at Melville, LA further downstream e a total drainage area estimate from USGS sources that appears to include ca. 50,000+ km2 drainage below Red River Landing and Simmesport, the 15,374 km2 non-contributing area attributed to the Red River @ Alexandria, but not the 57,800 km2 non-contributing area noted upstream for Vicksburg • examination of cases in the present data set having both “drainage area” and “contributing area” reported shows: • if accurate, the particular drainage area selected yield significantly different specific runoff estimates or otherwise affect hydrologic modelling • that these metadata are not reported consistently • the combined non-contributing area reported for upstream Platte/Missouri gauges of 48,586 km2 vanishes at the downstream Missouri @ Hermann, MO gauge for reasons that are not obvious • the combined non-contributing area of ca. 57,600–57,800 km2 is internally consistent for the Canadian/Arkansas system and the Mississippi @ Vicksburg gauge • the Red River system also appears to have ca 15,000 km2 closed drainage in the upper reaches • drainage areas reported for gauges below the Mississippi–Atchafalaya connecting channel are not consistent with figures given for gauges higher up the system • there are likely similar unreported cases in the arid / semi-arid US; e.g., huge drainage areas are often reported for gauges in the Rio Grande system by unofficial sources 16.3.1 Drainage Areas Given in this data set • • present metadata generally include the gross drainage areas as given by USGS users may wish to substitute other areas listed above or determine drainage areas from high resolution digital data now available 16.4 Lower Mississippi and Atchafalaya 247 16.4.1 General Background • • • • • the joint Mississippi–Atchafalaya discharge and drainage area are often taken to represent the Mississippi River as a whole WMO and RIV have a constructed record for combined Mississippi and Atchafalaya River discharges the Atchafalaya was formerly a distributary of the Red River that split off the Red River before the Red joined the Mississippi [Figures 16.1 and 16.2] manipulations dating back to the 19th century have effectively routed most Red River discharge down the Atchafalaya the Old River connecting channels, according to conditions, allowed water to move from the Mississippi to the Atchafalaya and vice versa Figure 16.1 Lower Mississippi, Atchafalaya and Old River connecting channels. [figure courtesy of US Army Corps of Engineers New Orleans District — www.mvn.usace.army.mil/pao/oldriver/] • • • • in the 1940s, Mississippi waters began to move increasingly down the Old River to the Atchafalaya as the Mississippi sought a faster route to the Gulf of Mexico about 1953, control works were begun to maintain the proportion of Mississippi waters moving down the Atchafalaya at about 1950 levels [30%] a new diversion channel from the Mississippi to the Atchafalaya was created north of the former [Lower] Old River connecting channel between the Red/Atchafalaya and the Mississippi [Figure 16.2] the control works became operational in 1961 248 • currently, ca. 25% of Mississippi waters are routed into the Atchafalaya on an average annual basis Figure 16.2 Detail of new Outflow Channel and [Lower] Old River connecting channels [figure courtesy of US Army Corps of Engineers New Orleans District — www.mvn.usace.army.mil/pao/oldriver/] 16.4.2 US Army Corps of Engineers gauges • many river gauges in the Lower Mississippi basin are operated by the US Army Corps of Engineers [USACE], and current data are not readily available in the USGS national repository • the gauges below are operated by USACE; data in USGS archives are incomplete 1. 2. 3. 4. Mississippi @ Vicksburg, MS Mississippi @ Tarbert Landing, MS Mississippi @ Red River Landing, LA Atchafalaya @ Simmesport, LA • discharge data for Mississippi @ Tarbert Landing, MS and Atchafalaya @ Simmesport, LA are available at [www.mvn.usace.army.mil/eng/edhd/Wcontrol/discharge.htm] • some reports and sketch maps have not accurately described the locations, drainage areas or operations of gauges 2-4 • Tarbert Landing, MS is ca. 6.3 river km upstream of Red River Landing, LA between the new Outflow Channel and the Lower Old River junction this gauge began operations in 1932, but continuous discharge data are only presently available date from 1960 [older records may be available from USACE by formal request] • 249 • • • • • • • • • • • Red River Landing, LA is located below the Lower Old River junction with the Mississippi this gauge has stage [water level] data from 1851–1923 and 1940–present in NCAR ds551, the USGS gave monthly discharge data for 1928–1964 no discharge data are currently available from on-line USGS sources because there were no stage data collected from 1924–1939, discharges given in ds551 for this period may have been estimated from an upstream gauge Vicksburg, MS is well upstream of the new Outflow Channel and the [Lower] Old River junction, and both Red River Landing and Tarbert Landing gauges mean annual Vicksburg discharges have been consistently greater than both Red River Landing and Tarbert Landing mean annual discharges for available data from 1928 this confirms that both the lower gauges have consistently reflected the routing of a significant fraction of lower Mississippi waters down the Atchafalaya system Simmesport, LA is ca. 8 km downstream of junction of the Red/Atchafalaya River and the [Lower] Old River this gauge began operations in 1887, but continuous operation dates from 1903 presently available discharge records begin in 1928 [older records may be available from USACE by formal request] 16.4.3 Estimating Total Discharge of the Mississippi–Atchafalaya System • to 1961, total Mississippi–Atchafalaya discharge can be taken as the sum of discharges for 1. Mississippi @ Red River Landing 2. Atchafalaya @ Simmesport, LA • since 1961, the combined Mississippi–Atchafalaya discharge can be taken as the sum of discharges for 1. Mississippi @ Tarbert Landing 2. Atchafalaya @ Simmesport, LA • overlapping 1961–1964 data for the two Mississippi gauges are essentially identical, i.e., the same data appear to have been reported for both gauges since the completion of the modern control works in 1961, any differences observed between discharge measurements taken at the two sites should be negligible (within the margin of errors) • 250 16.5 Pseudo Records US data in WMO and RIV compilations contained the following pseudo records: 16.5.1 Mississippi @ Red River Landing and Atchafalaya @ Simmesport • section 16.4 elaborated the discharge routing through the lower Mississippi– Atchafalaya system • the pseudo record Mississippi @ Red River Landing and Atchafalaya @ Simmesport given in UNESCO files (WMO, RIV) was discarded, and the two contributing gauge records were restored • the Aug 1928 discharge given by WMO/RIV (90,650 m3/s) for Mississippi @ Red River Landing and Atchafalaya @ Simmesport is an obvious error and was deleted 16.5.2 St. Lawrence River @ Ogdensburg / St. Lawrence @ Cornwall/Massena WMO # USGS # River gauge name Lat Lon Area Alt mean flow km2 m m 3/s 9549 4264000 St Lawrence Ogdensburg, NY US 44.70 -75.50 764,600 -99 214.2 9550 9492 4264331 St Lawrence Cornwall ON nr Massena, NY US St Lawrence Cornwall CA 45.00 -74.78 45.00 -74.80 774,410 -99 774,000 47 226.9 241.8 • St Lawrence @ Ogdensburg is not currently available as a USGS discharge record. As per notes from other USGS sources, these discharge data were published until 1970 under USGS gauge ID # 4264000 [currently the ID # of a water quality monitoring site]. • St. Lawrence @ Cornwall/Massena is not a gauge as US notes explain below: “Discharge is determined from summation of discharge through the Robert MosesRobert H. Saunders power dam, the Long Sault Dam, the Massena Diversion, the Rasin River Diversion, the Cornwall and Massena municipal water supply, and the Cornwall and the Wiley-Dondero navigation canals. US–Canada coordinated discharge figures are supplied by Corps of Engineers. Prior to 1956, base gage at lock 25 at Iroquois Ont. with supplementary gages. August 1956 to June 1958, 251 base gage at lock 24 between Iroquois and Morrisburg, Ont., and supplementary gages. Prior to Aug. 1956, these were gages of the Canadian Hydrographic Service and from August 1956 to June 1958, were gages of the Hydro-Electric Power Commission of Ontario.” “Discharge in the reach of river at Cornwall, Ont.– near Massena, NY is considered to be the same as discharge at Ogdensburg, NY when adjusted for storage in Lake St. Lawrence.” • Presently, the unique 1860–1972 Ogdensburg record appears only in WMO. • “Lake St. Lawrence” did not exist before the completion of the power plant barrage and navigation lock system in the late 1950s It is unclear when genuine discharge measurements began, but there are water level records dating back to the mid-1800s, so there is a basis for developing reasonable pseudo discharge data for the St. Lawrence River. • • • Because US and Canadian records for Cornwall and Cornwall/Massena are virtually identical where they overlap except for minor numerical jitter due to unit conversions and rounding, the Canadian record has been deleted from the present set. [see Canada: St. Lawrence @ Cornwall] • The US Cornwall/Massena record begins in 1934 and is updated annually or less frequently. The fragment in WMO spans 1973–84. Records now available from the USGS national archive (1934–1999 in July 2001) differ slightly, i.e., the record appears to have been revised back to 1934. • RIV compilers reduced the Ogdensburg and Cornwall/Massena records to a single series comprising Ogdensburg to 1972, and Cornwall/Massena thereafter — This is wrong ! The effects on coarse summary statistics may not be too significant. The Ogdensburg and Cornwall/Massena can likely be intercalibrated to approximate consistent long term records at either location. • The unadulterated Ogdensburg and Cornwall/Massena records are given in this data set. 16.5.3 Miscellaneous Doppelgangers Evidently, pseudo gauge records at locations other than gauge sites have entered the USGS national archive. These may represent water quality monitoring sites or other locations with discharge data borrowed from nearby discharge gauges. These pseudo records appear in the archive as if they were genuine gauge records. 252 Regrettably these are not clearly identified, and staff at national headquarters have apparently been unaware of these cases which have crept into the national archives. The US records in UNESCO files four pairs of apparent doppelgangers listed below. Data for the apparent active gauges (yellow shading) were retained. USGS ID WMO # # 7263500 Lat Lon River Gauge name state 34.75 -92.27 Arkansas Little Rock AR Drainage area km2 † Alt m 68.2 7263450 9554 34.79 -92.36 Arkansas Murray Dam nr Little Rock AR 409,451 409,296 3438500 3438220 9581 37.15 88.41 Cumberland 37.02 88.22 Cumberland Smithland nr Grand Rivers KY KY 46,395 45,579 6892500 6892350 9594 39.06 -94.87 Kansas 38.98 -94.96 Kansas Bonner Springs Desoto KS KS 155,213 224.4 154,768 231.3 6805500 9591 41.03 -96.30 Platte 41.02 -96.16 Platte South Bend Louisville NE NE 221,000 222,221 68.2 91.3 91.4 317 307 † The US Army Corps of Engineers also claims to have a gauge labelled Arkansas @ Little Rock with slightly different coordinates and drainage area. USACE data are identical to the two nominal USGS gauges. 16.6 Discontinuations and muddled substitutions • • • There are at least four cases among US sites in WMO/RIV where a gauge was discontinued and data from a new or nearby gauge were substituted by UNESCO as if from the previously active gauge. For the Alabama, Sacramento and Yukon gauges, the WMO record contained mixed data from old and “new” gauges. The records for both “old” and “new” gauges as given by the USGS have been included here. For the Pecos River at Shumla, the one year (1965) in WMO, was pre-pended it to the Langtry record that starts in 1966, and the distinct Shumla record was dropped. The local office of the USGS may have other data for Shumla. The drainage area difference between the two gauges is so small, that the error for using Shumla record at Langtry is practically nil. RIV compilers did the same. WMO # USGS # river gauge Lat old new 9545 10117 2429500 2428400 Alabama Alabama Claiborne AL 31.55 Claiborne Landing nr Monroeville AL 31.61 old new 9558 10116 11447500 11425500 Sacramento Sacramento Sacramento Verona 253 CA 38.58 CA 38.77 2 Alt m -87.51 -87.55 56,894 55,615 0.1 -121.5 -121.6 60,885 55,040 0 0.9 Lon Area km — old new 9566 10104 15564800 15453500 Yukon Yukon Ruby nr Stevens Village AK 64.74 -155.49 AK 65.88 -149.72 old new 9607 9608 8447400 8447410 Pecos Pecos Shumla nr Langtry TX TX 29.83 -101.38 29.80 -101.45 670,807 508,415 45.7 73.2 91,069 91,113 353.4 345.4 16.7 Boundary Gauges • • data for boundary gauges appear to be shared between the boundary nations, i.e., US-Canada, and US-Mexico the only differences between the records appearing the archives of each party appear to be trivial jitter due to rounding and unit conversions [Canada & Mexico use SI, while the USA continues to give data in imperial units] • St Lawrence @ Cornwall ON nr Massena, NY was discussed above Colorado River — International (US–Mexico) Boundary WMO # RIV # River Gauge Lat Lon Area El US NA 9628 358 Colorado Limite Internacional Norte 32.72 -114.72 638,950 30 US NA US NA 9628 10037 358 Colorado Colorado NIB u/s Morelos Dam nr Andrade, CA SIB nr San Luis, AZ 32.72 32.50 -114.72 -114.81 638,950 638,950 30 - • • • • • WMO and RIV included site W9268/R358 identified as “Limite Internacional Norte” these data likely came from Mexican archives the site also appears in the archives of the USGS and the IBWC identified as “NIB u/s Morelos Dam nr Andrade, CA” [NIB = Northern International Boundary] the gauge is located at the junction of Mexico and the US states of California and Arizona despite the name, i.e., “nr Andrade, CA”, the USGS assigns this gauge to Arizona, i.e., search on-line in the state of Arizona not California • some investigators have used NIB data as given by WMO/RIV to represent the outflow of the Colorado River to the sea (Gulf of California / Pacific Ocean); however, there is another border gauge further downstream that registers lower discharges • Arizona protrudes further south with the Colorado River forming the southwestern boundary with Mexico there is another boundary gauge downstream at the southwest corner of Arizona identified as “SIB nr San Luis, AZ” [SIB = southern international boundary] • 254 • for the available records, Colorado River discharge drops by roughly 1/2 between NIB and SIB • because the NIB record as given in WMO/RIV has been incorrectly adopted by some as representing the discharge of the Colorado to the Gulf of California, the record for Colorado @ SIB nr San Luis, AZ has been included in the present set under ID 10037 • • • the available metadata give the same drainage areas for NIB and SIB in natural circumstances, SIB drainage area would be somewhat larger in either case, the natural drainage areas are not practically meaningful as most Colorado waters are diverted to southern California or lost to enhanced evapotranspiration induced by impoundments, irrigated agriculture and other consumptive use in the US Rio Grande / Bravo — International (US–Mexico) Boundary WMO# RIV# River Gauge MX NA US NA 9645 9645 1091 1091 Bravo Rio Grande (Bravo) Matamoros, MX Matamoros, MX / Brownsville, TX US NA 9557 365 Rio Grande (Bravo) Laredo, TX / Neuvo Laredo, MX • • in the US this is known as Rio Grande (often redundantly as the Rio Grande River) in Mexico this is known as Río Bravo • these two gauges (Matamoros/ Brownsville, and Laredo / Neuvo Laredo) appear to be jointly operated data for both are available from www.ibwc.state.gov/ • • • • the UNESCO files gave 1976-1979 data for gauge 9645 presumably from Mexican sources for operational reasons, gauge 9645 has been re-named and re-designated as a US gauge in the present set records for both gauges have been updated from www.ibwc.state.gov/ Columbia @ International Boundary (US–Canada) WMO # RIV # 9526 9617 275 USGS # Columbia 12399500 Columbia Lat International Boundary, BC CA International Boundary, WA US 255 Lon Area km2 El m 49.00 -117.63 49.00 -117.63 155,000 154,622 400 396 • these two records are essentially the same gauge record that appear in the catalogues of both Canada and the USA • a record designated Columbia @ International Boundary (Canada) with data for 1938–1984 appears in both WMO and RIV a record designated Columbia @ International Boundary (USA) with data for 1965–1984 appears in WMO • • complete, annually updated data for the site are available from the USGS (to Sep 1999 at the time of writing) • differences between the nominally Canadian version and the US version are practically negligible; there are minor discrepancies that are likely due to rounding and SI-imperial conversion • • thus, record WMO 9526 / RIV 275 is dropped USGS data from 1938–1999 are retained under ID WMO 9617 Kootenai @ nr Copeland, ID replaced with Kootenai @ Porthill, ID WMO # RIV # USGS # River Gauge Lat Lon El m area discharge km2 km3 runoff mm 9505 278 12318500 Kootenai nr Copeland, ID 48.91 -116.42 518 34,706 13.7 396 10100 12322000 Kootenai Porthill, ID 49.00 -116.50 518 35,483 14.2 400 777 0.4 4 difference • Kootenay is the name used in Canada, while Kootenai is used in the US • the gauge Kootenai nr Copeland is listed in both US and Canadian catalogues, and was designated falsely in UNESCO files as Canadian gauge, but this site is unequivocally located on the US side of the border in Idaho • slightly downstream [the Kootenai flows north at this point], almost exactly on the US-Canada border, is another US gauge Kootenai @ Porthill, ID which began operations 7 months before Kootenai nr Copeland • • the differences in drainage area, discharge and runoff for the two gauges are virtually nil on 761 concurrent months of record the only apparent reason for operating two Kootenai gauges in such close proximity may have been that at least one stream entering between the two gauges drains some Canadian territory • the USGS discontinued the Kootenai nr Copeland, ID gauge in 1992 256 • because Kootenai @ Porthill, ID continues to operate and completely covers the same operational period as Kootenai nr Copeland, ID, the latter is dropped in favour of Kootenai @ Porthill, ID under the ID # 10100 • UNESCO data for Kootenai nr Copeland, ID span 1929–1984 and have scattered errata anyone wanting discharges for Kootenai nr Copeland, ID can readily obtain the complete 1929–1992 records from USGS on-line sources • • N.B. the flow regime changed appreciably from late 1973 as a major reservoir began operation and effectively damped out the natural seasonal cycle 257 17.0 Niger River Mid-basin Gauges 17.1 General Remarks • • • in Mali the Niger main channel is also called the Issa Ber the latter name is used mostly for the main channel through the inner delta — roughly from the confluence of the Niger and the Bani rivers to below Diré — where the main channel discharges likely do not represent all the water flowing the swampy terrain and minor side channels some sources use the name Issa Ber for the Niger throughout Mali • before considering discharge records, some problems with metadata, specifically uncertain drainage areas are discussed in the next section • several gauges on the main branch of the Niger River and one major tributary (Bani River) had multiple data sources that reduced to 2–3 alternate versions [generally, RIV, WMO and an independent version] that disagreed perceptibly amongst themselves • while disagreements involved the usual assortment of data entry errors and replications, more troubling problems emerged from the comparative analysis of data series over time • at several sites, the inter-relationships between alternate versions of the records as expressed by annualized (running 12-month) mean differences and root-meansquare differences, shift over time some of these changes involve abrupt shifts that define multi-year blocks when the fundamental character of one, the other or both alternate series has changed relative to the others unfortunately, it is rarely clear which is the recent and reliable version amongst the available alternates however, it is likely that, in a few cases, the outcome of sensitive statistical analyses will differ according to the particular version of the historical record that is employed • • • • • • at most sites, independent sources gave daily discharge series that were originally thought to be complete in the sense that they contained all available daily measurements; however, the monthly series derived from daily data often had significantly fewer months than were given in the UNESCO series this raises obvious questions about the legitimacy of those particular months in UNESCO series for which daily data are too few or absent to permit estimating the monthly averages it is possible, that the independently obtained daily discharge series are incomplete and that the UNESCO series were determined from complete sets of daily discharges 258 • however, it is equally possible that the UNESCO monthly series contain pseudo data generated by statistical or other methods 17.1.1 Problem Gauge Records • records for the five gauges below are especially troublesome WMO # River Gauge 62 61 63 64 15 Bani Niger Niger Niger Niger Douna Koulikoro Mopti Dire Niamey ML ML ML ML NE AF AF AF AF AF • all have 2–3 alternate versions that differ enough that the outcome of sensitive statistical analyses might differ according to the particular version of the series that was employed generally, for the present data set, monthly series derived from independently obtained daily data with in-fill of some missing values from UNESCO series were favoured without access to source agency personnel and data files, there is no way of knowing definitively that which record versions are the best accordingly, users may wish to examine the UNESCO data given by WMO and RIV; and if so, the errata noted in following sub-sections should be corrected before using those data • • • 9141 9142 9045 9046 9053 RIV # 17.2 Niger River Metadata — Uncertain Gauge Drainage Areas • drainage areas for main branch Niger River gauges listed in UNESCO sources including the GRDC catalogue are probably wrong • large discrepancies in reported drainage areas stem from poor definition of boundaries with two major closed basins on the north and northeast: (1) the Algerian Sahara (2) Lake Chad • revised drainage areas based on delineation of the Niger basin according to the GTOPO30 DEM (Olivera, 1995) and from a global watershed delineation based on STN-30p (Fekete et al. 1999) are listed in the table below: • sizable discrepancies between revised areas and those of UNESCO sources are seen for Dire, Ansongo, Niamey and Malanville gauges 259 • • • • • • • UNESCO areas for intermediate gauges: Koryoume, Tossaye, and Gaya are also likely wrong Gaya is across the river from Malanville and slightly downstream so that a drainage area of 1,515,500 km2 is a reasonable approximation based on Olivera et al.’s estimate for Malanville generally, the discrepancies become apparent below Mopti where the proportion of desert drainage area increases significantly upstream of Mopti, the areal discrepancies for Koulikoro and Ke-Macina are small the discrepancies between estimates by Olivera et al. and Fekete et al. likely reflect the general difficulty in delineating watershed boundaries in desert terrain these larger estimates likely include significant areas that rarely contribute runoff the lower UNESCO estimates likely give a better sense of areas that contribute most frequently to surface runoff WMO # RIV # River Gauge Lat Lon Drainage Area km2 Olivera et al. GN GN ML ML ML ML ML ML ML ML ML NE BJ NE 9963 1497 9142 9882 61 1505 9045 9046 63 64 9893 9053 9898 9052 1508 15 1466 1513 Niger Niger Niger Niger Niger Niger Niger Niger Niger Niger Niger Niger Niger Niger Kouroussa Tiguibery Koulikoro Kirango aval Ke-Macina Tilembeya Mopti Dire Koryoume Tossaye Ansongo Niamey Malanville Gaya 10.65 11.25 12.87 13.72 13.95 14.15 14.50 16.26 16.67 16.93 15.67 13.51 11.87 11.88 -9.88 -9.17 -7.57 -6.05 -5.37 -4.98 -4.20 -3.38 -3.03 -0.58 0.50 2.12 3.38 3.45 119,029 Fekete et al. UNESCO 18,000 70,000 121,466 136,517 15,205 69,875 120,000 137,000 141,000 143,300 281,600 340,000 342,000 348,000 566,000 700,000 1,000,000 1,000,000 143,361 372,588 308,186 367,900 726,619 850,479 1,515,224 647,527 791,121 1,399,238 17.3 Independently Obtained Daily Data Sets • • • independently obtained daily discharge sets were available for numerous gauges generally, monthly data series derived from daily data were given precedence in comparisons with UNESCO monthly data because the risks of data corruption are smaller with daily data, i.e., data entry errors have to be very large or the entire month has to be corrupted for the monthly mean of daily data to be much affected some small sets of daily discharges, generally recent data comprising irregular record fragments with missing pieces, were given less credence, as these were more likely to have been collections of provisional data that may have since been revised 260 • daily data sets for some Niger central basin gauges yield some significant differences with the UNESCO monthly data series, or suggest that some UNESCO monthly series have significant segments that have likely been developed from incomplete daily data, sometimes even for months with no daily data if adjacent months have a few measurements • estimating discharges during periods of gauge malfunction or other circumstances is not uncommon; the usual practice is to indicate that the reported daily discharges are estimates • these Niger River daily data series differ in that days with no measurements are left as missing values • if these daily data are reduced to monthly means by rejecting all months with incomplete data, several sites will have significantly fewer months of data available than in the UNESCO series, though both data sets nominally span the same period 17.3.1 Estimating monthly means from incomplete daily records • the following scheme was used to obtain and classify the monthly mean discharge estimates from daily series for months with incomplete data: • data for missing days were estimated by linear interpolation between the measured days surrounding the record gaps • two estimate classes were defined: 1. low risk 2. high risk • low risk months were of two types: a) a single record gap of no more than nine days b) multiple gaps with a mean gap length of 6.5 days or less for the month • high risk months were any other months with missing data that had at least one measured day reported • low risk condition b) allows estimates for as few as 4 measured days a month provided that they are spaced 7 days apart these are large rivers for which discharges change relatively slowly; so that, the risk of significant error in estimating the monthly mean from weekly manual measurements is small in most months • 261 • there is greater risk for months of the wet season that are prone to greater variation in daily discharge rates inspection showed that most wet season months were monitored continually, and that intermittent measurements are confined mainly to the dry season and the adjacent transition months • • • the results are summarized below L-days and L-months are numbers of low risk days [L-days] estimated and months with at least one L-day but no H-days H-days and H-months are numbers of high risk days [H-days] estimated and months with at least one H-day • • nearly all the estimates occur at 5 Niger River basin gauges • if the daily data series available to me were complete in the sense of having all available daily measurements, the originators of the UNESCO monthly series constructed estimates for some months that have no daily measurements, but the adjacent months had some daily measurements # River Gauge 9045 9053 9046 9898 9141 9882 9142 Niger Niger Niger Niger Bani Niger Niger Mopti Niamey Dire Malanville Douna Kirango aval Koulikoro Days L-days estimated L-months estimated H-days estimated 16,108 20,384 21,520 10,082 15,566 972 29,919 588 500 334 48 18 3 0 57 19 34 16 4 1 0 786 503 202 251 479 15 0 H-months Total months estimated estimated 11 24 5 9 5 1 0 17.3.2 Missing Feb 1 of Leap Years: sites 9045, 9046 and 9898 • • daily data for three Niger gauges: Mopti, Dire and Malanville are missing Feb 1 discharges of all leap years likely due to some data processing error by whomever compiled these particular data sets it is possible that Feb 1 was pushed to Feb 2 and other months were affected; however, the consequences to monthly averages of time-shifting a daily series by one day are practically insignificant for large watersheds like these 17.4 Niger @ Koulikoro WMO # RIV # River Gauge 262 68 43 39 25 9 2 0 ML AF • • • • • • • • • • 9142 61 Niger Koulikoro this site has long, nearly complete records from 1907–1990 R61, W9142 and a monthly series derived from independently obtained daily discharges (IND) set span 1907–1988 RIV and IND also have data for 1989–90 IHD has data for 1907–72 that are identical to RIV the plot below shows the running 12 month mean differences between the series to Jul 1980, WMO is steadily less than IND by an average of about 8 m3/s which is only about 0.5% of mean annual discharge relative to WMO and IND, RIV is generally greater and drifts modestly to mid 1957 about mid 1957, RIV shifts abruptly relative to WMO and IND becoming about 50 m3/s smaller than these on an annualized average basis, and subsequently drifts erratically to the early 1980s in the early 1980s, all three series converge to near equality WMO is mildly unstable through the 1980s, and may have been constructed from provisional records 12 month mean difference m3/s 50 30 10 -10 -30 riv - wmo riv - ind ind - wmo -50 -70 -90 -110 1910 • 1920 1930 1940 1950 1960 1970 1980 1990 as IHD and RIV are identical to 1972, RIV contains records submitted 25 years ago that have not been subject to any retrospective revisions that may be inherent in WMO and IND which appear to have been obtained during the early 1990s by retrieval of the entire historical record 263 • IND was retained for the present set, with 1989 filled in from RIV • for anyone choosing to use R61, 3 significant typos with suggested replacement values expected from record intercalibrations are listed below: 1913 7 1931 8 1981 8 R61 W9142 IND replacement value 956.0 2977.0 29.5 638.5 3891.0 2932.6 650.2 3916.8 2953.2 655.8 3952.5 2942.9 17.5 Niger @ Kirango ML AF • • • • • • WMO # RIV # River Gauge 9882 1505 Niger Kirango aval • WMO has no data RIV records span 1925–1980 with some missing blocks an old independent set (IND1) has monthly records spanning 1925–1952 a slightly more recent independent set (IND2) has monthly records for 1925–1958 these three sources are all missing 1941–1949 a 3rd independent set (IND3) is a loose collection of daily discharges for part of 1981, and all of 1987 and 1990 a GRDC annual summary gives annual averages and extrema for 1925–1992 • all the available sources differ somewhat from each other 1925 – Oct 1950 • • from 1925 to Oct 1950, the recent GRDC summary data and the old IND2 have discharges that are systematically lower than IND1 and RIV which are similar on concurrent months specifically the concurrent months of R1505 and GRDC extrema follow the systematic relations shown below 264 8000 Niger @ Kirango: GRDC–RIV relations for discharge >250 cms; 1925–1950 7000 GRDC cms 6000 5000 4000 3000 2000 1000 Y = 0.989X - 28.346 0 0 1000 2000 3000 4000 5000 6000 7000 8000 R1505 cms 250 3 2 y = -0.000003882x + 0.002961086x + 0.289259411x + 5.424346431 GRDC cms 200 150 100 Niger @ Kirango; GRDC– RIV relations for discharge <250 cms; 1925–1950 50 0 0 50 100 150 200 250 300 R1505 cms • • • it appears that the GRDC series and R1505 originate from the same data, and differ only by a systematic adjustment in terms of annual averages, those given by R1505 are ca. 2.5–4% higher than those given by GRDC however, the differences on low discharges are substantial; R1505 low discharges are 19–46% higher than those given by GRDC 265 • • where they can be compared (1925–54), RIV and IND2 are nearly identical for most data, but there are scattered discrepancies two that are probable typos in RIV are listed below: 1929 1939 5 11 RIV IND seasonal 592 4485 142 2310 65 2239 Nov 1950 – 1990 • • from Nov 1950 RIV and GRDC are similar, but there are scattered discrepancies with no obvious patterns for the two full years of daily discharges, i.e., 1987 and 1990, IND3 annual average and monthly extrema are identical to GRDC Data Retained • W9882 Niger @ Kirango aval, based on R1505 as is for 1925– Oct 1950 with a few missing months filled from other sources with adjustment where appropriate • presently, without access to source records of the national agency, there is no obvious basis for choosing GRDC over R1505; although, the low season discharges given by R1505 do seem high 17.6 Bani @ Douna WMO # ML AF 9141 RIV # 62 River Gauge Bani Douna • • • • W9141 spans 1952–1988 GRDC summary data span 1922–1994 from 1952–1988, GRDC annual averages and extrema are identical to W9141 practically then, the GRDC record for 1922–1951 and W9141 for 1952 can be considered as a coherent set • • R62 spans 1922–88 with some missing pieces IHD is identical to RIV on 1922–72 implying that to 1972, the R62 record contains data submitted to UNESCO 25 years ago • an independent set (IND) of daily discharges spans 1922–81 with numerous gaps before 1950 and again in the 1960s • both IND and RIV have a long record gap from Jan 1938 – Sep 1949 266 • RIV, IND, WMO and GRDC are identical from 1982–1988 • 1. 2. 3. in summary, there are three versions to contend with: IND monthly means from daily discharges RIV monthly means GRDC/WMO annual averages and extrema to 1950 and WMO monthly means thereafter • numerous record gaps, scattered typos and perceptible differences among the available data sets make this the most troublesome of the Niger gauges to analyze • the daily series (IND) has the cleanest record but is missing many months present in the others RIV has ubiquitous typos and many months not in the others; however, many of these are months that have incomplete or no daily discharges; this raises the question of how these monthly discharges were derived WMO has a only few errata and a few months not in the others • • mean discharge cms 1200 1000 800 600 400 200 19 22 19 25 19 28 19 31 19 34 19 37 19 40 19 43 19 46 19 49 19 52 19 55 19 58 19 61 19 64 19 67 19 70 19 73 19 76 19 79 19 82 19 85 19 88 19 91 0 IND • RIV GRDC the annual discharge plot (above) suggests there are 4 distinct periods: a) 1922 – Dec 1933 when IND has systematically lower flows than R62 and GRDC b) 1934–1937 and Oct 1949 – Oct 1951 when differences between alternates are much smaller than before 1934; these data are very similar in character to block c 1952–1981 data, but the relationships between alternate versions as expressed by calibration plots differ slightly c) Nov 1951 – Dec 1981 when IND, RIV, and WMO/GRDC have small systematic differences and RIV has numerous typos 267 d) 1982–1988 when all versions are identical except for one typo in RIV • • on the three temporal blocks when the three alternates are distinct (i.e., a, b and c above), the alternates all intercalibrate reasonably well for blocks a and b, the relationships are very strong with little scatter, while for block c (1952–1981) the relationships are somewhat noisy • there is little doubt that the three versions originate from the same source data, and that differences among the three result from arbitrary scaling adjustments, estimated discharges for months that apparently lack complete daily data, and data entry or transcription errors in the case of RIV • because the alternates intercalibrate well, aberrant data can be readily identified and replaced with estimates consistent with the other two alternates, and many missing months in each series can be filled with good quality estimates 17.6.1 Estimated Monthly Averages for Months with Incomplete Daily Discharges • • • the IND monthly series includes the following estimate for months with incomplete daily data Low Risk estimates are labelled “L”, and High Risk estimates are labelled “H” these all compare well with monthly means given in one or both alternates estimate 1930 2 1932 10 1933 7 1933 10 1955 12 1966 7 1967 2 1968 8 1969 1 28.0 L 3215.0 H 348.8 H 2311.7 L 555.2 H 41.8 L 82.1 H 903.7 L 123.7 H 17.6.2 1922–1933 • • there are perceptible systematic differences between IND, RIV and GRDC these discharges are also higher than those of all periods that follow 268 10000 discharge cms 1000 100 10 1 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 GRDC • • • RIV to make this plot, the GRDC series was estimated by calibration relations between the GRDC set of annual minima and maxima with IND and/or RIV because the calibration relations are so strong (see below), the estimated GRDC discharges should be a very close facsimile of the actual GRDC data series the intercalibration relations between alternates are very strong with most data falling on or near straight or mildly curved lines hence; all three alternates originate from the same source data but differ by systematic adjustments 4500 4000 3500 GRDC cms • IND 3000 2500 2000 1500 Calibration plot: GRDC–IND 1922–1933 1000 500 0 0 500 1000 1500 2000 2500 IND cms 269 3000 3500 4000 4500 • • • by general order of magnitude, IND < RIV < GRDC in relative terms, the differences are greatest in low season discharges, but all discharges are affected this period has the highest discharges on record, so it is unclear why the creators of the series given by RIV and GRDC saw fit to scale discharges even higher IND RIV GRDC J F M A M J J 140 165 230 70 89 127 41 55 88 21 35 60 16 30 52 27 42 67 167 190 250 A S O N D mean 1128 2488 1192 2637 1334 2819 2557 2682 2846 1194 1274 1413 379 421 506 686 734 816 17.6.3 1934 – Oct 1951 • • differences amongst the alternates are much smaller the inter-record calibrations remain very strong with little scatter 17.6.4 Oct 1951 – Dec 1981 • • • RIV, WMO and IND are near equality, but all disagree by small systematic differences the calibration relations have perceptibly more scatter; however, relative scatter is still small and there is no doubt that these series are strongly inter-related RIV is riddled with inconsistencies with the other two series that are likely transcription and data entry errors 17.6.5 Data Retained • • • • • the series retained is a composite of IND from 1922–1982 and WMO from 1982– 1988 IND is retained because it is the most complete series and seems to be closed to the original source data there is no reason to believe that the RIV and GRDC versions of the series are in any way superior; indeed, they seem to be the product of arbitrary data re-scaling unless they are backed up with compelling analysis and rationale, there is no reason to accept either over IND after the initial 1922–1933 period, differences amongst alternates are small enough that the impact of choosing IND over the others is relatively minor for most practical purposes 270 17.6.6 Missing months estimated from RIV and WMO • • in total, RIV mostly and WMO have 46 months when IND has no data calibrated estimates derived from these data are included in the present data set yr mo estimate yr mo estimate 1923 2 1930 11 1930 12 1934 1 1934 2 1934 3 1936 3 1936 4 1936 5 1936 6 1950 1 1950 2 67.2 833.3 310.9 74.6 71.7 57.6 70.8 54.8 35.0 53.8 73.4 39.7 1950 3 1950 4 1950 5 1951 7 1958 9 1958 10 1959 1 1959 2 1959 3 1959 4 1962 3 1962 6 21.3 16.0 10.8 100.2 2958.9 2282.7 213.6 128.7 73.2 34.4 37.7 36.6 • • • • • yr mo 1964 1964 1964 1964 1965 1966 1966 1966 1966 1966 1967 1967 3 4 5 6 4 3 4 5 6 9 4 6 estimate yr mo estimate 45.0 26.0 37.2 53.4 53.0 44.3 28.7 20.2 28.0 1800.0 29.5 27.6 1967 11 1967 12 1968 1 1968 2 1968 3 1968 4 1968 5 1968 6 1968 7 1969 2 1200.3 336.2 174.7 96.0 60.0 40.0 34.3 53.5 250.9 63.3 it is unclear how RIV and WMO discharges for these months were derived daily discharge records may exist that were not in the IND set a cursory check shows that for many of these months the discharges are close to what would be predicted by basic Markovian forecasting models; hence, these discharges may be estimates however, if these discharges are estimates, they seem to be reasonably good estimates they can be omitted from sensitive analyses as desired 17.7 Niger @ Mopti WMO # ML AF 9045 RIV # River Gauge 63 Niger Mopti • • • WMO and RIV have identical data spanning 1922–1975 an independently obtained set of daily discharges (IND) spans 1922–1981 another small independent set of daily discharges for 1990 was appended to IND • N.B. references suggest that there are likely two gauges operating at / near Mopti one is referred to as Mopti; and the other as Nantaka or Mopti-Nantaka virtually identical location coordinates and drainage areas are given for both • • 271 • records from two distinct gauges and mixed records from two gauges may explain some of the differences evident in available data series • • in the main block of data (1922–75), there are numerous gaps before 1950 IND also has several short gaps in the 1960s and 1970s, implying that if IND represents the complete daily discharges available, the ostensibly “complete” UNESCO series has been patched with estimates for several periods in the 1960s and 1970s for months that have no daily measurements • there are so many gaps that comparative analysis is difficult; nonetheless, inspection shows that historically there are significant differences between the two series to the late 1960s • the figure below shows the smoothed 12 month running mean (AV12) and rootmean-square (RMSD12) differences for Jul 1943 — Dec 1975 where, to obtain a plot, some approximations were made to cross small gaps in 1949, the 1960s, and 1970s positive differences mean that IND data are larger than UNESCO data 300 AV12 RMSD12 200 m3/s • 100 0 1940 1950 1960 1970 1980 Figure xx. Smoothed running 12 month mean (AV12) and root-mean-square (RMSD12) differences between IND and UNESCO monthly series. 272 • • • over 1968–75, IND and UNESCO series are near parity except for the Jul-Dec 1972 when UNESCO data increase relative to IND inflating AV12 and RMSD12 a calibration plot of 1968–75 data confirms that, despite some scatter, IND and UNESCO data generally fall along the y=x line of equivalence from the late 1940s through 1967, IND data are perceptibly higher than UNESCO data, and visual inspection of record fragments before the late 1940s, suggests that the large difference may have prevailed all the way back to 1922 Annual Peak Monthly Discharges • • • historically, the annual peak monthly discharges given by IND are 10–20% higher than WMO/RIV to 1967 the average difference was 484 m3/s after 1967, the differences range from -1 to 3.5%, i.e., WMO/RIV annual peak monthly discharge exceeds IND in some years Annual Minimum Monthly Discharges • • • historically, the annual minimum monthly discharges given by IND are 10–20% lower than WMO/RIV up to 1957 (low season discharges are missing altogether in both series for several years) the average difference was 15 m3/s after 1957, the differences are generally much smaller, but more erratically variable, with large percentage differences some years, and IND minima often exceeding WMO/RIV minima Inter-record Calibration • the calibration plot below shows that there are significant differences between IND and UNESCO data particularly at high and low discharges: a) at discharges > 2000 m3/s, IND data are appreciably higher than UNESCO discharges b) for discharges 1000–2000 m3/s, data from the two series are practically identical b) at discharges of 200–1000 m3/s, IND data can be lower or higher than UNESCO data d) at discharges of <200 m3/s IND data are generally lower than UNESCO 273 • • • • this plot and cursory checks also indicate that the calibration between the IND dailyderived data and the UNESCO series is governed by multiple relations these might be for specific chronological subsets and/or monthly or coarser seasonal aggregates, and may be further broken out by discharge class an ad hoc analysis suggests that seasonal differences may explain the odd bifurcation for discharges between 200–1000 m3/s, but even on a monthly basis relations between IND and UNESCO data often have slope breaks or curvature exhaustive analysis of the many potential data groupings would be needed to determine viable calibration equations between IND and UNESCO data between 1922–1967 3000 y=x 1922-1967 UNESCO 2500 2000 1500 1000 500 0 0 500 1000 1500 2000 2500 3000 3500 4000 IND Figure xx. Calibration between IND and UNESCO monthly series, 1922–1967. • • the monthly IND series was retained without going to the source agency, there is no way to determine whether IND is superior to UNESCO data, but the IND data are likely more recent • series IND includes 68 estimates from incomplete daily data: 57 of the Low Risk class (L), and 11 of the High Risk class (H) — these are listed below 274 • 12 of the Low Risk estimates involved Feb of leap years that were missing Feb 1; only two of the 12 cases were missing other days estimate 1924 1924 1926 1927 1928 1936 1936 1936 1944 1948 1952 1956 1959 1959 1960 1961 1962 1962 1962 1962 1963 1963 1963 2 7 3 7 2 2 3 6 2 2 2 2 11 12 2 11 9 10 11 12 3 4 5 419.3 L 842.7 L 370.9 L 799.3 L 669.6 L 311.4 L 154.2 L 238.0 L 197.5 L 146.7 L 951.3 L 658.6 L 3176.0 L 1955.2 L 329.5 L 2911.3 L 2684.6 H 3272.8 L 3367.2 L 2501.1 L 256.2 L 99.6 L 88.6 L estimate 1963 1963 1963 1963 1963 1964 1964 1964 1964 1964 1964 1964 1964 1964 1964 1965 1965 1966 1966 1967 1967 1967 1967 6 9 10 11 12 2 3 4 5 6 8 9 10 11 12 5 6 7 12 4 5 6 7 93.4 H 2478.8 L 3005.4 L 3174.3 L 2233.5 L 372.0 L 149.5 L 77.9 L 53.8 H 96.2 L 1968.3 L 2939.3 L 3453.6 L 3413.1 L 2584.0 L 68.9 L 121.2 L 297.4 L 2226.0 L 76.0 L 47.3 H 60.6 L 408.2 L estimate 1968 2 1968 4 1968 5 1968 6 1968 11 1968 12 1969 4 1969 5 1969 6 1970 5 1970 6 1971 3 1971 4 1971 5 1971 6 1971 7 1971 9 1972 2 1972 6 1976 2 1977 7 1980 5 540.6 L 103.9 L 76.1 L 261.5 L 2571.7 L 1455.0 L 48.2 H 35.3 L 76.0 L 64.9 H 90.1 H 83.1 H 40.3 H 24.0 H 16.0 H 300.3 L 2513.3 L 139.3 L 244.2 L 177.3 L 272.0 L 12.5 L 17.7.1 UNESCO data not in IND • • the UNESCO series include 36 months that correspond to months in IND having have incomplete or no data such that no mean could be estimated about 50% of these months had some days in IND but monthly means were not estimated because adjacent months on one side had no data; so that, the interpolation was being driven by data several months remote, often on the opposite side of the low discharge season, with the result that estimates would be too high • if the IND daily discharges are the complete records [in the sense of having all available daily data] for the Mopti gauge, it’s unclear how the UNESCO monthly means were derived for these months with poor data, and the other 50% with no data at all • these 36 months were retained after adjustment to rough IND equivalence by rough calibration using a graphing program feature to fit polynomials and make predictions 275 • • • • • data had to be grouped seasonally [i.e., by one or more adjacent months] within the distinct time blocks noted above to obtain passable results simple linear fits were only adequate in two cases, otherwise 3rd or 4th order polynomials were required the odd bifurcation of the IND–UNESCO data between 200–1000 m3/s is illustrated by comparison of the cases of Jul 1928 where a fit based on Jul data from 1922–48 adjusts the RIV discharge of 715 downward to 630, while based on March data for 1922-48, the Mar 1929 RIV datum of 285 is adjusted upward to 350 to approximate IND equivalence hence; scaling adjustments of these data seem to have been done on a seasonal basis these 36 adjusted UNESCO data were retained, but they should be regarded as high risk estimates that users should be prepared to delete as necessary UNESCO adjusted 1924 1924 1924 1924 1925 1925 1925 1926 1926 1927 1927 1927 1927 1927 1928 1928 1928 1928 3 4 5 6 3 4 5 4 5 2 3 4 5 6 3 4 5 6 150 70 50 350 270 160 100 120 80 230 100 70 65 100 230 130 90 270 154 54 29 310 328 168 89 114 66 266 88 54 48 90 270 127 78 241 dif UNESCO adjusted 4 -16 -21 -40 58 8 -11 -6 -14 36 -12 -16 -17 -10 40 -3 -12 -29 1928 1929 1929 1929 1936 1936 1943 1946 1949 1962 1962 1962 1966 1966 1966 1972 1972 1972 7 3 4 5 4 5 6 10 7 4 5 6 4 5 6 3 4 5 715 285 150 105 95 70 80 2810 98 60 41 109 68 43 33 78 55 40 630 350 154 95 82 54 71 3230 90 49 47 100 58 48 34 74 52 38 dif -85 65 4 -10 -13 -16 -9 420 -8 -11 6 -9 -10 5 1 -4 -3 -2 17.8 Niger @ Dire WMO # ML AF • • 9046 RIV # River Gauge 64 Niger Dire WMO and RIV have identical records spanning Jul 1924 – Dec 1979 an independent set of daily discharges (IND) spans Jan 1924 – Dec 1981, and daily discharges for 1987 and 1990 obtained separately were appended 276 • both IND and the UNESCO sets have sporadic short record gaps • • GRDC summary data span 1924–1992 at the beginning and end of the series, GRDC summary data are virtually identical to IND from the late 1960s through 1981, GRDC alternates between having the highest or lowest mean annual discharges the relative behaviour is not consistent long enough to infer scaling relations with the others; hence, GRDC data have not been considered • • • the plot below of running 12 month mean (AV12) and root-mean-square (RMSD12) differences shows that there are perceptible differences between IND and the UNESCO data, and that the relationship between the two shifts significantly in the 1960s and 1970s 300 AV12 RMSD12 200 m3/s 100 0 -100 1930 • 1940 1950 1960 1970 1980 there are 5 distinct periods: 1) from 1924–1948, IND averages ~ 50 m3/s < UNESCO on an annualized basis 2) from Jul 1949 – Jun 1964, IND averages ~ 35 m3/s < UNESCO on an annualized basis 3) from Jul 1964 – mid 1969, IND jumps abruptly to average ~ 37 m3/s > UNESCO on an annualized basis 277 4) from late 1969 – mid 1973, IND jumps to average ~ 93 m3/s > UNESCO on an annualized basis 5) from early 1975 – Dec 1979, IND jumps again to average ~ 160 m3/s > UNESCO • for the present data set, the IND monthly series was retained • it’s unclear whether IND or UNESCO is superior, and there is a perceptible risk of developing spurious time trends by using the wrong data series • series IND includes 39 estimates from incomplete daily data: 34 of the Low Risk class (L), and 5 of the High Risk class (H) — these are listed below • 15 of the Low Risk estimates involved Feb of leap years that were missing Feb 1 — only 2 of these cases were missing other days estimate 1924 1925 1925 1925 1926 1928 1932 1936 1940 1944 1944 1944 1944 • • • 2 10 11 12 10 2 2 2 2 1 2 3 4 1525.3 2049.8 2347.5 2609.7 1889.7 2105.2 1387.5 1421.0 1430.5 1464.0 875.2 306.1 51.1 estimate L L L L L L L L L L L L L 1944 1944 1948 1952 1956 1960 1964 1968 1972 1973 1973 1973 1973 5 6 2 2 2 2 2 2 2 5 9 10 11 7.5 1.0 691.4 2222.5 2033.3 1436.6 1441.7 1844.8 674.6 20.9 1354.3 1592.5 1633.2 estimate L L L L L L L L L L L L L 1973 1975 1975 1976 1980 1980 1980 1980 1981 1981 1981 1981 1981 12 5 6 2 2 5 6 7 4 9 10 11 12 1343.6 14.7 17.3 910.9 643.9 14.3 11.7 66.1 34.0 1570.6 1908.0 2009.9 1699.3 L L H L L H H H L L L L H some scattered potential typos in RIV / WMO are listed below the expected values derive from rough calibrations between IND and UNESCO using polynomial fits the most potentially significant discrepancies have been highlighted in green 1925 1930 1930 1930 1930 1930 1944 1944 1944 1948 3 1 2 3 4 5 2 3 4 3 IND UNESCO expected 1409 2308 1925 1372 714 239 875 306 51 217 1505 2614 2213 1574 890 333 1050 530 170 286 1445 2355 2008 1406 768 257 921 332 68 233 278 † %dif 4.1 10.4 9.7 11.3 14.8 25.8 13.0 46.0 85.4 20.6 † 1949 1950 1964 11 2 1 1946 1190 1969 2141 1096 1897 1994 1223 2018 7.1 -11.0 -6.2 1977 10 1660 1020 1410 -32.1 between UNESCO and expected values 17.8.1 UNESCO data not in IND • • • • the UNESCO series have 12 months for which daily discharges in IND are too incomplete or absent to permit estimating a monthly mean these 12 months were retained after adjustment to IND equivalence by rough calibration with a graphics program feature to fit polynomials and make predictions fitting was done according to the distinct chronological periods identified previously these 12 adjusted UNESCO data were retained, but they should be regarded as high risk estimates that users should be prepared to delete as necessary yr mo RIV adjusted dif 1949 1949 1949 1949 1949 1949 1 2 3 4 5 6 1550 1100 550 170 55 50 1508.7 1061.0 519.9 152.7 43.5 37.8 -41.3 -39.0 -30.1 -17.3 -11.5 -12.2 1973 1974 1974 6 6 7 5 10 200 17.2 17.4 270.4 12.2 7.4 70.4 1979 1979 1979 6 3 8 136 319 898 174.8 439.3 1107.8 38.8 120.3 209.8 17.9 Niger @ Ansongo ML AF • • • WMO # RIV # River Gauge 9893 1508 Niger Ansongo R1508 has 1950–1980 with scattered missing months an independent source (IND) has daily discharges for 1987 and 1990 a GRDC summary has annual averages and monthly extrema for 1950–1991 279 • • • • • • • the calibration between R1508 and the GRDC data reveal some discrepancies in R1508 despite some scatter, the calibration line falls almost exactly on the line of equivalence, i.e., y=x Mar–Jun as given in R1508 are likely shifted 1 month ahead in time according to GRDC, the minimum monthly discharge of 11 (yellow-shading) occurs in Jun this discharge appears as a significant outlier on the calibration plot a qualitative check against 1972 discharges downstream at Niamey supports the arrangement of Ansongo discharges for Jan–Jun as shown on the second line below it is not possible to judge from Niamey discharges whether the Aug–Nov Ansongo data given by R1508 were affected by the time-shift J R1508 1972 1972 F M A M J J A S O N D 1790 1234 1234 531 531 106 106 55 55 11 - 263 263 425 425 937 937 1573 1573 - • • • for Jun 1973, R1508 discharge = 78.2 is likely in error GRDC gives 7 and the Niamey discharge is only 10 the Jun R1508 entry may be a decimal shift error, i.e., 78.2 should really be 7.82 • for anyone who checks, the GRDC 1973 maximum discharge of 1620 occurring in Dec should likely be 1260 which would be consistent with R1508 and Niamey • the joint R1508 / IND set augmented with scattered months from the GRDC series of annual extrema was retained under ID W9893 some GRDC annual minima that were flagrantly inconsistent with Niamey were excluded • 17.10 Niger @ Niamey, Malanville and Gaya NE AF BJ AF NE AF † • WMO # RIV # River Gauge 9053 † 9898 9052 15 1466 1513 Niger Niger Niger Niamey Malanville Gaya Area 850,479 1,515,224 1,515,500 W9898 is an independent data source; Niger @ Malanville was not in WMO data for these gauges are somewhat muddled in WMO and RIV 280 • • • • • • WMO and RIV contain record fragments that have been replicated within gauge records and sometimes between gauge records WMO contains some fragments that may be from other gauges WMO and RIV records contain sporadic, significant typos the best record appears to be an independent set (IND) of daily discharges for Niamey spanning 1929–1991 (same period as WMO and RIV) with some missing pieces Malanville and Gaya gauges have poorer quality data that is evident by the interrelationships between discharges at these three gauges more so than by the number of obvious discrepancies — these two gauges are virtually across the river from each other; so that, records should be practically identical after cleaning the dubious pieces from WMO and RIV, the record for Niamey was built up by using the independent record and filling missing data with RIV and WMO in that order wherever possible 17.10.1 Niger @ Niamey • IND are monthly data derived from an independently obtained set of daily discharges 17.10.1.1 Typos and Data Entry Errors • • • Jul – Dec 1967 at RIV are replicated in Jul–Dec 1969 with minor variations, 1967 in W9053 is replicated in 1968 and Jan–Jun 1969 these do not appear to be legitimate data from this site J F 1967 1968 1969 1970 1914 2166 1896 2236 W9053 1967 1968 1969 1970 IND R15 1967 1968 1969 1970 M A M J J 1935 2306 1702 2285 1437 556 1975 1139 1017 321 1844 847 163 357 89 225 58 114 37 79 55 184 55 51 427 1392 1413 1609 1879 648 1009 1294 1549 1763 427 1392 1413 1609 1879 252 838 1197 1434 1680 1750 1762 1766 2236 1755 1771 1769 2285 1433 1449 1437 1844 845 853 839 847 335 335 328 225 123 123 120 79 123 125 53 51 500 1093 1266 1427 1613 506 1090 1267 1430 1618 581 1222 1467 1648 1904 252 838 1197 1434 1680 1913 2177 1892 2245 1935 2313 1695 2293 1440 583 1978 1152 1035 351 1845 860 159 377 97 248 35 102 33 86 32 183 56 53 440 1397 1416 1601 1876 674 1030 1305 1544 1755 606 1236 1466 1639 1904 278 858 1211 1437 1670 281 A S O N D • • • May 1971 R15 is an obvious typo Jul–Aug 1971 W9053 are likely typos, and Sep–Dec disagree with R15; this suggests that the entire Jul–Dec 1971 sequence may have been wrongly patched in from another gauge Feb–Jun 1972 W9053 are wrong J F M A M J J R15 1971 1795 1435 W9053 1971 1795 1435 IND 1971 1788 1436 617 617 647 179 179 197 530 53 56 18 18 19 47 119 47 258 921 1216 1478 1749 496 1083 1269 1435 1631 274 925 1231 1470 1745 R15 1972 1790 1302 493 W9053 1972 1779 1762 1402 IND 1972 1784 1307 530 140 804 163 43 311 48 20 114 23 121 121 129 690 1044 1245 1399 1613 690 1044 1245 1399 1613 680 1021 1218 1376 1526 • • O N D WMO/RIV IND 3 488 1201 1198 1363 1471 1003 1003 3 69 495 1167 1154 1332 1437 975 6 7 8 9 10 11 12 1 several typos in R15 and W9053 are listed below 1930 1934 1936 1936 1961 1971 1990 • S it seems very likely that in both W9053 and R15, the Jul 1985 entry was skipped and entries for Aug 1985 – Jan 1986 were backshifted 1 month from Jan 1986 the series are back in sync 1985 1985 1985 1985 1985 1985 1985 1986 • A 5 8 1 6 9 5 1 IND W9053 R15 834.6 255.0 1736.1 93.9 1314.3 56.4 777.9 816.0 225.0 1640.0 -9.0 304.0 53.0 877.0 -9.0 225.0 -9.0 939.0 304.0 530.0 877.0 except for pre-1962 discrepancies listed above, IND and the UNESCO series are virtually identical on all months having complete data up to 1961 282 17.10.1.2 R15, W9053, and IND intercomparisons • • • • • • beyond the typos listed above, R15 and W9053 are virtually identical, except for 1973–1975 where there are modest but perceptible differences the root-mean-square-difference (RMSD) between W9053 and IND is smaller (62% of RMSD between W9053 and R15) which suggests that for anyone wishing to use the UNESCO series, 1973–1975 data from W9053 are better than those from R15 IND was compared to a composite UNESCO monthly series, free of the typos and other discrepancies noted above, and with W9053 patched in for 1973–75 the running 12 month mean (AV12) and root-mean-square differences (RMSD12) are shown below in both rough and smoothed versions (both AV12 and RMSD12 are very sensitive to even a relatively modest single difference in the 12 months being averaged — smoothing takes off the spikes) IND and UNESCO are identical to 1961 except for 1941-43 when all months in both series have likely been estimated from incomplete daily data as the AV12 line shows, differences over 1941-43 are fairly small, but some larger (but small in percentage terms) differences occur from mid 1942 through Dec 1943 that drive up RMSD12 • whoever estimated the UNESCO means for months with incomplete daily data did not use linear interpolation • • • the most importance differences are observed from 1961–1986 through the 1960s, IND tends to be higher than the UNESCO composite, in the early 1970s, the UNESCO composite abruptly becomes perceptibly higher than IND in the 1980s, the UNESCO composite falls relative to IND until the final years (1987–91) when the two series become nearly identical again • • • • the reason(s) why these two data series diverge from 1961–1986 is not obvious nor is it clear which is the better representation of the discharge at Niamey the quirky variations in these series are not large enough to affect rainfall-runoff modelling, water budgets and other coarse-grained hydrological computations, but low and high discharges are affected enough to potentially induce spurious conclusions about the kind of hydroclimatic trends that are currently of much interest • in the present data set, monthly series IND derived from the independently obtained daily discharge series has been retained some missing data were filled directly from the UNESCO composite • 283 40 AV12 RMSD12 30 m3/s 20 10 0 -10 -20 -30 1930 1940 1950 1960 1970 1980 1990 Figure xx. Running 12 month mean (AV12) and root-mean-square (RMSD12) differences between IND and UNESCO monthly series. 40 AV12 RMSD12 30 m3/s 20 10 0 -10 -20 -30 1930 1940 1950 1960 1970 1980 1990 Figure xx. Smoothed running 12 month mean (AV12) and root-mean-square (RMSD12) differences between IND and UNESCO monthly series. 284 17.10.1.3 Months of IND series estimated from incomplete data • 43 months estimated from incomplete data are listed below with the L and H class indicating Low Risk and High Risk estimates respectively Estimate 1930 6 1930 7 1931 4 1935 7 1935 8 1936 7 1941 1 1941 2 1941 5 1941 6 1941 7 1941 8 1941 9 1941 10 1941 11 1941 12 1942 1 1942 2 1942 3 1942 4 1942 5 329.8 384.9 1320.8 64.9 314.3 285.7 1449.7 1328.1 88.3 27.5 24.2 311.1 721.9 1000.1 1227.5 1424.7 1501.2 1376.6 817.3 247.1 68.6 Class Estimate H H L H L H H H H L L L L L L L L L L H H 1942 1942 1942 1942 1942 1942 1942 1943 1943 1943 1943 1943 1943 1943 1943 1943 1943 1943 1943 1944 1947 1980 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 7 6 8 28.4 67.8 369.7 859.0 1059.1 1241.6 1418.4 1432.3 1234.0 559.5 140.0 41.3 19.3 26.2 360.1 1151.8 1249.2 1298.8 1495.2 8.9 66.5 467.9 Class H H L H L L H H H H H L L L L L L L L H H L • there are 8 cases where the absolute % difference between these estimates and those in UNESCO series range from 10–20%; 5 of these cases are low flows when the percentages are inflated because the magnitude of discharges are small; and the other 3 are high risk cases when the month had only 1-3 days of measured data (the UNESCO monthly mean would be equally suspect in these cases) • as most estimates are concentrated in 1941–43, the issue of using these estimates is generally of much less concern than the divergence of the two series between 1961–86 when data are virtually complete 285 17.10.1.4 Months in UNESCO series but not in IND • • • • • the UNESCO series includes 18 months for which IND that had too few or no daily data that to estimate monthly means these were included in the present data set as is the months in the 1930s and 1940s are considered high risk; IND had only a few or no days during the these short gaps the Feb – Jun 1980 sequence might be based on daily data not included with IND the final 1991 sequence extends past the end of IND record and is assumed to be correct UNESCO 1931 1932 1941 1941 1944 1947 3 6 3 4 6 5 1730 100 900 430 20 180 UNESCO 1980 1980 1980 1980 1980 1980 1 2 3 4 5 6 1904 1325 476 125 32 12.5 UNESCO 1991 1991 1991 1991 1991 1991 4 5 6 7 8 9 52.8 69 143 91 741 1224 17.10.2 Niger @ Malanville • data were available in R1466 and an independently obtained series of daily discharges (IND) • on months with complete daily data, the two series are virtually identical except for the data entry error below • • Aug 1964 of R1466 is replicated shifting other months ahead to Dec 1964 IND has the correct sequence 1964 8 1964 9 1964 10 1964 11 1964 12 1965 1 • R1466 IND 982 982 2,152 1,793 1,434 1,793 982 2,151 1,793 1,434 1,570 1,793 the only other differences occur on a few days when monthly discharges were estimated from incomplete daily data 286 • Feb 1 data for leap years in the set of daily discharges were missing (Feb 29 data are present) • in all cases, discharges on days preceding and following Feb 1 are nearly identical; hence, the differences between IND estimates and R1466 are negligible in four of six cases • two of four cases, R1466 data for Feb 1968 and 1972, are likely typos, as it’s highly improbable that the missing Feb 1 discharges in the IND daily set could have deviated enough from discharges on days before and after to have produced the discrepancies in monthly means shown below IND 1956 1960 1964 1968 1972 1976 • • 2 2 2 2 2 2 2132 1817 1774 2284 1508 1813 R1466 dif 2130 1820 1775 2125 1475 1810 2 -3 -1 159 33 3 E E E E E E IND includes the following 25 months estimated from incomplete daily data unlike at other locations, whomever constructed the Malanville UNESCO series did not attempt to estimate monthly discharges on months with incomplete daily data Estimate Class 1956 1960 1961 1964 1966 1968 1968 1968 1968 1969 1969 1972 1973 2 2 7 2 4 2 5 6 8 4 5 2 1 2132.3 1816.6 177.2 1774.0 889.1 2284.0 587.4 282.6 1007.5 486.4 214.8 1508.5 1384.9 Estimate Class L L H L H L H H L H L L H 1973 1973 1976 1978 1980 1980 1980 1980 1980 1980 1980 1980 287 2 3 2 4 5 6 7 8 9 10 11 12 839.5 329.4 1812.5 69.4 47.2 50.2 455.9 609.2 1094.1 1165.8 1306.0 1397.1 H H L L L L L L H L L L 17.10.3 Niger @ Gaya • • Jan–Mar 1965 recurs in Jan-Mar 1966 for both W9052 and R1513 these data are inconsistent with 1966 data at Niamey and Malanville 9052 9052 • • 1965 1966 J F M A M J J A S O N D 1896 1896 2169 2169 2001 2001 1350 825 500 300 350 250 300 100 800 280 1590 1045 1539 1370 1492 1336 1538 1539 for both W9052 and R1513, the Jul 1969 – Jun 1970 data are the W9053 discharges at Niamey the correct Jul 1969 – Jun 1970 discharges for Gaya are not available J M A M J J 9052 9052 1969 1931 1883 1153 1970 2236 2285 1844 450 847 203 225 106 79 53 120 581 1222 1467 1648 1904 585 1471 1522 1398 1605 9053 9053 1969 1766 1769 1437 1970 2236 2285 1844 839 847 328 225 120 79 53 51 581 1222 1467 1648 1904 252 838 1197 1434 1680 • • • A S O N D the four values below are likely typos in R1513 according to historical patterns at the upstream sites (Malanville and Niamey), the Jun 1984 discharge is more likely to be 29.5 m3/s than 2.95 or 295, but 2.95 is at the low end of the plausible range, so it was left as is 1960 10 1971 9 1980 9 1984 6 • • F WMO R1513 DIF 1689 1248 1008 2.95 1609 248 108 295 80 1000 900 -292 %_dif seasonal 5 134 161 196 1424 1399 1399 132 the Apr–May 1978 discharges in W9052 / R1513 are likely erroneous the historical patterns at the upstream sites suggest that the expected Gaya discharge should be 50–100 m3/s these two discharges were deleted 288 • the Feb–Mar 1990 Gaya discharges are suspiciously high, but these were plausible for the high end of the range seen on the receding seasonal flood discharges, so they were left as is Niamey WMO/RIV Niamey IND Malanville WMO/RIV Gaya WMO/RIV 1978 4 1978 5 67 32 63 29 74 465 531 1990 2 1990 3 1990 4 296 106 41 296 106 39 - 482 422 402 289 References: Arora, V.K., and Boer, G.J. 2001. 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