Report on the operation of North Pine Dam

Transcription

January 2013
Flood Event
Report on the
operation of
North Pine Dam
26 March 2013
EXECUTIVE SUMMARY
Background and Lead In
Ex-Tropical Cyclone Oswald tracked along the east coast of Queensland as a low pressure system during
mid-January 2013, resulting in large rainfall and flooding conditions in numerous river systems. In response to
rainfall forecasts for South East Queensland, a temporary full supply level of 38.4 m AHD (representing
approximately 88% of full supply volume) was declared for North Pine Dam on 25/1/2013.
In response to the declared temporary full supply level and the forecast rainfall conditions over the coming
days, the Seqwater Flood Operations Centre was mobilised on 25/1/2013 with the initial function of managing
the releases from North Pine Dam to the temporary full supply level.
Rainfall that resulted in the Flood Event commenced in the North Pine Dam catchment during 25/1/2013 with
generally small rainfall depths recorded on that day. Rainfall was widespread across the catchment with
increasing intensity during 26/1/2013 and 27/1/2013. The most intense rainfall of the Flood Event was
observed on 27/1/2013 between 00:00 and 12:00 within the North Pine Dam catchment.
The rainfall resulted in large inflows to North Pine Dam. The rainfall and subsequent run-off resulted in the
declaration of a Flood Event in the North Pine Dam system under the Manual of Operational Procedures for
Flood Mitigation at North Pine Dam (Revision 7) on 27/1/2013 at 12:15.
The peak inflow to North Pine Dam was estimated to be approximately 1,650 m3/s.
Dam Operations
The Manual of Operational Procedures for Flood Mitigation at North Pine Dam, Revision 7, does not provide
for operating to meet the requirements of a declaration of a temporary full supply level. A Revised Interim
Program of the Moreton Resource Operations Plan was made on 25/1/2013, prescribing an allowable
operational release rate of up to 300 m3/s while lake levels are below 39.6 m AHD and a Flood Event has not
been declared.
Dam operational releases commenced from North Pine Dam at 20:00 on 25/1/2013 to achieve the declared
temporary full supply level. These occurred at a rate of approximately 300 m3/s during the night to limit
disruption to downstream communities. The dam lake level dropped to 38.37 m AHD and operational
releases ceased at 8:15 on 26/1/2013. Youngs Crossing was closed to traffic during this period of operational
releases.
Operational releases recommenced from North Pine Dam at 20:00 on 26/1/2013 to maintain the dam lake
level near the temporary full supply level. These operational releases were gradually increased up to a rate of
300 m3/s. A Flood Event was declared at 12:15 on 27/1/2013 when the North Pine Dam lake level was
predicted to exceed 39.6 m AHD.
Following the declaration of a Flood Event, releases from North Pine Dam were progressively increased from
420 m3/s at 17:00 up to 830 m3/s at 22:00. During this period, dam lake levels peaked at 39.80 m AHD.
In response to slowly dropping dam lake levels and reduced ongoing rainfall, release rates from North Pine
Dam were progressively reduced from 00:00 on 28/1/2013 to 6:00 on 29/1/ 2013 when gates were closed and
the dam lake level was 38.80 m AHD.
At 14:30 on 29/1/2013 the Flood Operations Centre was notified that the temporary full supply level for North
Pine Dam had been revoked effective immediately. At this time, the dam lake level was 38.85 m AHD and
0.75m below the permanent full supply level. As a result, the Flood Event for North Pine Dam was declared
complete and no further gate releases performed.
Page i
Figure E-1 – North Pine Dam; Modelled Inflows, Outflows and Lake Level
Flood Attenuation
North Pine Dam does not include a dedicated flood mitigation storage allowance and it is normally operated
such that peak outflow is the same or slightly lower than peak inflow. In this Flood Event, factors including the
temporary full supply level and adopted operating strategy resulted in a large reduction in peak dam outflow
when compared to the peak inflow rate.
Event Magnitude
The catchment conditions preceding this rainfall event were very dry, resulting in a very high initial loss of
rainfall when converting this to run-off. As a result, the magnitude of the run-off event was generally less than
the magnitude of the rainfall that caused it.
The North Pine Dam catchment average rainfall was 529 mm in this event. The highest point rainfall depths
were recorded in the northern and western extents of the North Pine Dam catchment, with Baxters Creek,
Raynbird Creek and Mt Mee gauges recording rainfall intensities equivalent to 1 in 50 AEP for durations
greater than 24 hours. The overall catchment average rainfall intensities for the North Pine River to North
Pine Dam catchment were between the 1 in 20 AEP and 1 in 50 AEP for rainfall durations between 12 hours
and 120 hours.
The flood volume passing through North Pine Dam from this Flood Event is estimated to be approximately
97,000 ML. This volume is approximately half that of the January 2011 Flood Event.
Systems Review and Compliance
Generally, systems developed to support the operational management of the Flood Event performed well.
Flood operations were conducted in full compliance with the Manual of Operational Procedures for Flood
Mitigation at North Pine Dam, Revision 7 and operational releases were conducted compliant with the Revised
Interim Program of the Moreton Resource Operations Plan.
Page ii
CONTENTS
1.
Introduction ......................................................................................................................................... 1
1.1
Background and Purpose of Dam ......................................................................................................... 1
1.2
Flood Operation Objectives ................................................................................................................... 3
1.3
Report Writing Methodology .................................................................................................................. 3
1.4
Flood Event Key Times ......................................................................................................................... 4
2.
Lead In .................................................................................................................................................. 5
2.1
Seasonal Outlooks ................................................................................................................................ 5
2.1.1
Background ................................................................................................................................................................................ 5
2.1.2
Issued 22 August 2012 for September to November 2012 ........................................................................................................ 5
2.1.3
Issued 19 September 2012 for October to December 2012 ...................................................................................................... 6
2.1.4
Issued 24 October 2012 for November 2012 to January 2013 .................................................................................................. 6
2.1.5
Issued 21 November 2012 for December 2012 to February 2013 ............................................................................................. 7
2.1.6
Issued 21 November 2012 for December 2012 to February 2013 ............................................................................................. 7
2.1.7
Summary .................................................................................................................................................................................... 8
2.2
Catchment and Dam Status at Event Start ............................................................................................ 9
2.3
Forecasts Preceding Event ................................................................................................................... 9
2.4
Lowering of FSL .................................................................................................................................. 11
2.5
Forecast Flows at Event Commencement ........................................................................................... 11
3.
Event Readiness................................................................................................................................ 13
3.1
Preparedness ...................................................................................................................................... 13
3.1.1
Statement of Preparedness ...................................................................................................................................................... 13
3.1.2
Approved Engineers ................................................................................................................................................................. 13
3.1.3
Communications Equipment..................................................................................................................................................... 13
3.1.4
Confirmed Dam Release Infrastructure Status......................................................................................................................... 13
3.2
Mobilisation ......................................................................................................................................... 13
3.3
Staffing at the Flood Operations Centre .............................................................................................. 14
3.4
Staffing at Dams .................................................................................................................................. 14
4.
FLOOD EVENT DATA ........................................................................................................................ 15
4.1
Introduction.......................................................................................................................................... 15
4.2
Monitoring Network ............................................................................................................................. 15
4.3
Seqwater’s ALERT Network ................................................................................................................ 16
4.4
Seqwater’s ALERT Network Performance .......................................................................................... 21
4.5
Forecast Rainfall ................................................................................................................................. 22
4.6
Daily Rainfall ....................................................................................................................................... 23
4.7
Average Catchment Rainfall ................................................................................................................ 33
4.8
Catchment Temporal Patterns............................................................................................................. 34
4.9
Gauging Station Hydrographs ............................................................................................................. 34
4.10
Dam Water Levels, Gate Settings and Outflows ................................................................................. 35
5.
FLOOD modelling .............................................................................................................................. 37
5.1
Introduction.......................................................................................................................................... 37
5.2
Modelling Systems .............................................................................................................................. 37
5.2.1
The URBS Hydrologic Model.................................................................................................................................................... 37
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5.2.2
URBS Control Centre ............................................................................................................................................................... 38
5.2.3
FLOOD Modelling System ........................................................................................................................................................ 39
5.2.4
The Gate Operations Module ................................................................................................................................................... 39
5.3
Model Runs With and Without Forecast Rainfall ................................................................................. 40
5.3.1
Presentation of a Selection of Modelled Scenarios .................................................................................................................. 40
6.
Dam Operations................................................................................................................................. 43
6.1
Strategy Timeline and Selection .......................................................................................................... 43
6.2
Compliance with Operating Manual ..................................................................................................... 46
7.
Communications ............................................................................................................................... 49
7.1
Overview ............................................................................................................................................. 49
7.1.1
Summary Types of Communication ......................................................................................................................................... 49
7.1.2
Statement of Basis of Reporting ............................................................................................................................................... 49
7.1.3
Communications Protocol......................................................................................................................................................... 49
7.2
Situation Reports ................................................................................................................................. 49
7.2.1
Content and Preparation .......................................................................................................................................................... 49
7.2.2
Distribution of Situation Reports ............................................................................................................................................... 50
7.2.3
Situation Reports Issued .......................................................................................................................................................... 50
7.3
External Agencies ............................................................................................................................... 52
7.3.1
General Communications ......................................................................................................................................................... 52
7.3.2
Ministerial Briefing Advice ........................................................................................................................................................ 53
7.3.3
Information to the Public ........................................................................................................................................................... 53
7.4
Gated Dam Reports ............................................................................................................................ 53
7.5
Dam Operators .................................................................................................................................... 54
8.
FLOOD EVENT MAGNITUDE ............................................................................................................ 55
8.1
Introduction.......................................................................................................................................... 55
8.2
Rainfall Intensity .................................................................................................................................. 55
8.2.1
Point Rainfall Intensity .............................................................................................................................................................. 56
8.2.2
Catchment Rainfall Intensity ..................................................................................................................................................... 57
8.3
Comparison with Historical Rainfalls ................................................................................................... 58
8.4
Comparison with Historical Flood Volumes ......................................................................................... 59
8.5
Conclusion........................................................................................................................................... 59
9.
FLOOD ATTENUTATION ................................................................................................................... 61
9.1
Flood Attenuation ................................................................................................................................ 61
10.
Event Review ..................................................................................................................................... 63
10.1
Forewarning of the Event .................................................................................................................... 63
10.2
Monitoring Network ............................................................................................................................. 63
10.3
Forecast Rainfall during the Event ...................................................................................................... 63
10.4
Model Performance and Ratings ......................................................................................................... 64
10.5
Forecasting Systems ........................................................................................................................... 66
10.5.1
Enviromon, URBS and Gate Operations Module ..................................................................................................................... 66
10.6
Dam Operations .................................................................................................................................. 66
10.7
Review of the Manual .......................................................................................................................... 66
10.8
Staffing ................................................................................................................................................ 67
10.9
Communications.................................................................................................................................. 67
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10.10
Dam Damage Assessment .................................................................................................................. 67
11.
Recommendations ............................................................................................................................ 69
12.
References ......................................................................................................................................... 71
Page v
FIGURES
Figure E-1 – North Pine Dam; Modelled Inflows, Outflows and Lake Level ....................................................... ii
Figure 1-1 – North Pine Dam Infrastructure – Arrangement of the Radial Gates ...............................................2
Figure 1-2 – North Pine Dam Locality Map ........................................................................................................3
Figure 2-1 – Seasonal Outlook and Median Rainfall – Sep to Nov ....................................................................5
Figure 2-2 – Seasonal Outlook and Median Rainfall – Oct to Dec .....................................................................6
Figure 2-3 – Seasonal Outlook and Median Rainfall – Nov to Jan .....................................................................6
Figure 2-4 – Seasonal Outlook and Median Rainfall – Dec to Feb ....................................................................7
Figure 2-5 – Seasonal Outlook and Median Rainfall – Jan to Mar .....................................................................8
Figure 2-6 – Calculated Antecedent Conditions and Dams Levels at Event Start..............................................9
Figure 4-1 – Enviromon ...................................................................................................................................15
Figure 4-2 – ALERT Rainfall Network in SE Qld ..............................................................................................19
Figure 4-3 – Seqwater ALERT River Network in SE Qld .................................................................................20
Figure 4-4 – Daily Rainfall (mm) 24 hours to 09:00 24/01/2013 (Source: FEWS) ............................................26
Figure 4-10 – Rainfall (mm) 5 Days to 09:00 29/01/2013 (Source: FEWS) .....................................................32
Figure 4-11 – Catchment Average Rainfall (mm) for 5 Days to 09:00 29/01/2013 (Source: FEWS) ................33
Figure 4-12 – Average Catchment Rainfall – Catchment to North Pine Dam...................................................34
Figure 4-13 – Hydrographs – Inflows to North Pine Dam ................................................................................35
Figure 4-14 – North Pine Dam Water Level and Outflows ...............................................................................36
Figure 5-1 – URBS Model of North Pine catchment .........................................................................................38
Figure 5-2 – URBS Control Centre ..................................................................................................................39
Figure 5-3 – Modelled Inflow to North Pine Dam as at approximately 17:00 27/1/2013...................................41
Figure 8-1 – Annual Exceedance Probability of Flood (Source: AR&R) ...........................................................55
Figure 8-2 – Point IFD Analysis for Selected Stations .....................................................................................57
Figure 8-3 – North Pine River to North Pine Dam IFD Analysis .......................................................................58
Figure 9-1 – Comparison of North Pine Dam outflows; Event Recorded and Loss of Communications Case .62
Figure 10-1 – Forecast Rainfall Verification .....................................................................................................64
Figure 10-2 – Model Verification ......................................................................................................................65
Figure 10-3 – Model Verification ......................................................................................................................65
Page vi
TABLES
Table 1.1 – Key Event Times .............................................................................................................................4
Table 2.1 – Summary of Rainfall Outlooks .........................................................................................................8
Table 2.2 – Inflow and Outflow Scenarios at Event Commencement ...............................................................12
Table 4.1 – Seqwater ALERT Stations .............................................................................................................16
Table 4.2 – Sensors OOA at Event Start ..........................................................................................................21
Table 4.3 – Failed Sensors during Event .........................................................................................................21
Table 4.4 – QPF 24 Hour Forecasts .................................................................................................................23
Table 4.5 – PME 24 Hour Forecasts ................................................................................................................23
Table 4.6 – Daily Totals for Pine Rivers Basin (Source: Enviromon)................................................................24
Table 6.1 – North Pine Dam Operating Summary ............................................................................................44
Table 7.1 – Distribution of Situation Reports ....................................................................................................50
Table 7.2 – Situation Reports ...........................................................................................................................51
Table 7.3 – Ministerial Briefing Advice .............................................................................................................53
Table 8.1 – Point IFD Analysis for Selected Stations .......................................................................................56
Table 8.2 – Historical Total Rainfall ..................................................................................................................58
Table 8.3 – Comparison of Historical Flood Event Volumes ............................................................................59
Table B.1 – Pre Event Forecast Scenarios ......................................................................................................75
Table B.2 – Mid Event No Forecast Rain Scenarios ........................................................................................76
Table B.3 – Mid Event Forecast Rain Scenarios ..............................................................................................78
Table B.4 – Mid Event Actively Updated Scenarios .........................................................................................78
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Page viii
DOCUMENT HISTORY
Document History
Revision
Date Issued
Reviewed By
Approved By
Rev A
22/2/2013
Seqwater Project Report Team
Internal
draft
Rev B
4/3/2013
Dam Operations Manager, EGM Water
Delivery
Internal
draft
Rev C
12/3/2013
CEO Seqwater
Internal
draft
Rev D
14/3/2013
CEO Seqwater
Internal
draft
Ver 0
26/3/2013
CEO Seqwater
Revision
Type
For
submission
Distribution of copies
Revision
Copy no
Quantity
Issued to
Rev A
Not controlled document
Electronic
Project review team
Rev B
Electronic
Dam Operations Manager,
EGM Water Delivery
Rev C
Electronic
CEO Seqwater
Rev D
Electronic
CEO Seqwater
Ver 0
Chief Executive, DEWS
Document title:
Flood Event Report: North Pine Dam, January 2013
Version:
Ver 0
Date:
26/3/2013
Prepared by:
Seqwater
Approved by:
CEO Seqwater
File name:
W:\FloodS\20130123\Flood Event Administration\Event Report NPD\Ver
0\20130123_FER_NPD_Ver0.docx
Page ix
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Page x
GLOSSARY
In this report, the following terms are defined as below:
“Act” means the Water Supply (Safety and Reliability) Act 2008;
“Acceptable Flood Capacity” means the overall flood capacity required of a dam in accordance with DNRW
(the then Queensland Department of Natural Resources and Water) Guidelines on Acceptable Flood
Capacity, February 2007
“AEP” means Annual Exceedance Probability, the probability of a specified event being reached or exceeded
in any one year. This may be expressed as a ratio (e.g. 1 in Y) or a percentage;
“Agency” includes a person, a local government and a department of State government within the meaning
of the Acts Interpretation Act 1954;
“AHD” means Australian Height Datum;
“ALERT” means Automated Local Evaluation in Real Time System, a system of monitoring and displaying
rainfall and water level data. It is a combination of field stations, communications networks and data
collection software;
“AMTD” means the Adopted Middle Thread Distance, which is the distance along the centre line of the
mainstream from a junction, usually in kilometres;
“ANSI” means the American National Standards Institute;
“AR&R” means Australian Rainfall and Run-off (Book 6), The Institution of Engineers Australia (Engineers
Australia) national guidelines for the estimation of design flood characteristics;
“BoM” means the Commonwealth Government agency, the Bureau of Meteorology;
“Chairperson” means the Chairperson of Seqwater;
“CEO” means the Chief Executive Officer of Seqwater;
“Chief Executive” means the Director-General of the Department of Energy and Water Supply or nominated
delegate;
“Controlled Document” means a document subject to managerial control over its contents, distribution and
storage. It may have legal and contractual implications;
“Dams” means Somerset Dam and Wivenhoe Dam;
“Dam Crest Flood” means the flood event which, when routed through the storage with the storage initially at
Full Supply Level, results in the still water level in the storage reaching the lowest point in the dam
embankment, excluding wind and wave effects;
“Dam Operator” means the duty officer on site at Wivenhoe or Somerset Dam as the case may be;
“Dam Supervisor” means the senior on-site officer at Somerset or Wivenhoe Dam as the case may be;
“DERM” means the Queensland Government department, the Department of Environment and Resource
Management;
“DEWS” means the Queensland Government department, the Department of Energy and Water Supply;
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“DTMR” means the Queensland Department of Transport and Main Roads;
“Duty Flood Operations Engineer” means the Senior Flood Operations Engineer or Flood Operations
Engineer rostered on duty to be in charge of Flood Operations at the Dams;
“EL” means elevation in metres Australian Height Datum;
“FFS” means the Flood Forecasting System, being a suit of computer programs that utilise real time data to
assist in decision making during Flood Events described in more detail in Appendix H of the Manual;
“Enviromon” is the Bureau of Meteorology data collection software used to collect and display rainfall and
water level data;
“ERRTS” means Event Reporting Radio Telemetry System;
“Flood Event” has the meaning set out in Section 1.2 of The Manual;
“FEWS” is a software package developed by Deltares that incorporates a hydrological forecast and warning
system. A customised system for the Brisbane River incorporating Wivenhoe and Somerset Dam is currently
under development;
“FLOOD-Col” is a data collection software used in the Flood Operations Centre to collect and display rainfall
and water level data;
“FLOOD-Ops” is a modelling software used in the Flood Operations Centre to model the run-off from the
catchments;
“Flood Officer” means a person who:

Provides assistance to the Duty Flood Operations Engineer during flood events as directed by the Duty
Flood Operations Engineer; and

Undertakes routine flood preparation duties between flood events.
“Flood Operations Centre” means the office location used by Flood Operations Engineers during a flood
event to manage the event;
“Flood Operations Engineer” means a person designated to direct flood operations at the Dams in
accordance with Section 2.4 of the Manual;
“Flood Operations Engineers” means the collective group of persons who individually have designation as
either a Flood Operations Engineer or a Senior Flood Operations Engineer;
“Flood Operations Manager” means the Senior Flood Operations Engineer or Flood Operations Engineer
designated responsibility for the overall management of the Flood Operations Centre leading up to or during
a flood event;
“FSL” or “Full Supply Level” means the level of the water surface when the reservoir is at maximum
operating level, excluding periods of flood discharge;
“Gauge” when referred to in (m) means river level referenced to AHD or a local datum, and when referred to
in (m3/s) means flow rate in cubic metres per second;
“IFD” means Intensity Frequency Duration and refers to the statistical analysis of rainfall intensities;
“Manual” or “Manual of Operational Procedures for Flood Events at North Pine Dam” means the current
version (Revision 7) of the Manual;
3
“m /s” means a rate of water flow being one cubic metre of water per second or 1,000 litres of water per
second;
Page xii
“OOA” means ‘out of action’ in relation to the operation of a rainfall or river height gauge that provides
catchment data;
“PME” (Poor Man’s Ensemble) means the gridded rainfall forecast product from BoM;
“Protocol” means draft Communication Protocol prepared by DERM to ensure information is effectively
communicated to the public during flood events impacting North Pine Dam;
“QPF” means Quantitative Precipitation Forecast provided by the Bureau of Meteorology and is an estimate of
the predicted rainfall in millimetres, usually in the next 24 hours;
“RTFM” means Real Time Flood Model and is a combination of Flood-Col, Flood-Ops and other ancillary
software;
“SD” means State Datum, which is a level height datum that is different from AHD;
“Senior Flood Operations Engineer” means a person designated in accordance with Section 2.3 of the
Manual under whose general direction the procedures in the Manual must be carried out;
“Seqwater” means the Queensland Bulk Water Supply Authority, trading as Seqwater;
“URBS” means Unified River Basin Simulator.
Note: Dam levels in this document represented as metres (m) are metres Australian Height Datum or
(m AHD).
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Page xiv
1.
INTRODUCTION
This document comprises the required report relating to the January 2013 Flood Event which occurred at
North Pine Dam. This Flood Event report incorporates details of pre-event analysis commencing 23/1/2013,
operational releases from North Pine Dam from 25/1/2013 to 27/1/2013 and flood operations from 27/1/2013
to 29/1/2013.
1.1
Background and Purpose of Dam
A Flood Event is defined as a situation where the Dam exceeds Full Supply Level (FSL) and flood water
releases are made. In accordance with the Manual and the Water Supply (Safety and Reliability) Act (2008),
the owner of North Pine Dam (currently Seqwater), must prepare a report after each Flood Event. The report
must contain details of the procedures used during the Flood Event, the reasons why procedures were used
and other pertinent information.
North Pine Dam is an urban water supply dam with limited flood storage above FSL. The Manual refers to the
Dam having a “flood storage compartment”, however, the volume of this compartment effectively only provides
a short time delay between FSL being reached and flood releases commencing if the dam is full or near full at
the time. The flood storage compartment’s volume (the volume of water between FSL and the radial gate
opening trigger level) is 1,096 ML, which represents only 0.5% of the full supply volume of the dam and
provides no practical flood mitigation benefits during flood events. In general terms, once the dam is full,
floods will pass through the reservoir with only minor attenuation of the flood peak.
During flood events, significant inflows into the dam can occur within two hours of heavy rain commencing in
the catchment area. With limited flood storage, the floods pass through the dam quickly when the dam is at its
FSL of 39.60 m AHD.
Radial gates are the primary infrastructure used to release water during significant flood events at North Pine
Dam. Regulator valves may be used to manage lake levels in small events but generally remain closed if
radial gates are opened. The arrangement of the radial gates and regulator valves at North Pine Dam is
shown in Figure 1-1.
Page 1
Figure 1-1 – North Pine Dam Infrastructure – Arrangement of the Radial Gates
When a flood event is declared, the flood inflows are assessed to provide:

a prediction of the maximum storage levels in the dam

a prediction of the peak outflow rate from the dam.
Prior to water being released from the radial gates, the Flood Operations Engineer must ensure the Grant
Street causeway is closed to traffic and the Moreton Bay Regional Council has been advised of the potential
impact of flood releases on inundation of Youngs Crossing. Youngs Crossing has a very limited flow-carrying
capacity (approximately 10 m3/s) and a release from North Pine Dam using radial gates will inundate the
crossing. Outflows from the spillway of Sideling Creek Dam (a separate catchment to North Pine Dam) can
also impact Youngs Crossing.
In major flood events such as the January 2011 Flood Event, the northbound lane of Gympie Road at AJ
Wylie Bridge is also inundated when the flow in the North Pine River reaches approximately 900 m3/s.
Figure 1-2 shows the location of crossings impacted by dam releases.
Page 2
Figure 1-2 – North Pine Dam Locality Map
North Pine Dam is operated in accordance with clearly defined procedures during flood events to ensure the
safety of the Dam. The current procedures are contained in The Manual of Operational Procedures for Flood
Mitigation at North Pine Dam (Revision 7) which was gazetted in October 2012. The Manual is an approved
flood mitigation manual under the Queensland Water Supply (Safety and Reliability) Act 2008. An
understanding of the Manual is important when reading this Report.
1.2
Flood Operation Objectives
The primary objectives of the procedures contained in the Manual, in order of importance are:
1.
Ensure the structural safety of the dam
2.
Minimise disruption to the community in areas downstream of the dam
3.
Retain the storage at Full Supply Level (FSL) at the conclusion of the Flood Event
4.
Minimise impacts to riparian flora and fauna during the Drain-Down Phase of the Flood Event
In meeting these objectives, the dam must be operated to account for the potential impact of closely-spaced
flood events. Accordingly, normal procedures require stored floodwaters to be emptied from the North Pine
Dam as quickly as possible, while meeting all of the Manual’s objectives.
1.3
Report Writing Methodology
This report was prepared based on the Seqwater procedure, Event Report Writing Methodology. A summary
of this is contained in Appendix A of this report. The report was prepared to address Section 385 of the
Water Supply (Safety and Reliability) Act 2008 (Queensland Government, 2013), which prescribes specific
requirements for Flood Event Reporting.
Page 3
1.4
Flood Event Key Times
Key times and dates of the Flood Event are listed in Table 1.1.
Table 1.1 – Key Event Times
Milestone
Time
Event Modelling Start Date for use in the FFS
23/1/2013 9:00
Flood Operations Centre mobilised
25/1/2013 12:00
Temporary FSL declared for North Pine Dam
25/1/2013 14:15
North Pine Dam releases commenced
25/1/2013 20:00
Flood Event declared in event log
27/1/2013 12:15
North Pine Dam lake peak level
27/1/2013 21:00
Finish time of last gate release
29/1/2013 6:00
Temporary FSL revoked for North Pine Dam
29/1/2013 14:30
Event ended
29/1/2013 14:30
Page 4
2.
LEAD IN
This report section discusses the climatic, catchment and water storage conditions that preceded the Flood
Event.
2.1
Seasonal Outlooks
2.1.1
Background
BoM’s seasonal outlooks are general statements about the probability or risk of wetter or drier than average
rainfall over a three-month period. The outlooks, based on the likelihood of climatic conditions varying from
median conditions, are taken from Australian rainfall/temperatures and sea surface temperature records for
the tropical Pacific and Indian oceans. The seasonal outlook is not a categorical prediction about future
rainfall, and it does not predict rainfall patterns within individual months of the three-month outlook period.
The median, or decile 5, rainfall is the value which marks the level dividing the ranked data set in half; i.e. the
midpoint of the ordered (lowest to highest) monthly, seasonal or yearly precipitation totals.
The seasonal outlook in the lead up to the January 2013 Flood Event is described herein.
2.1.2
Issued 22 August 2012 for September to November 2012
http://www.bom.gov.au/climate/ahead/archive/rainfall/20120822.shtml
Mixed spring rainfall outlook for Australia
The national outlook for spring (September to November) indicates that:

a drier than normal season is likely for large parts of southeast and northeast Australia

a wetter than normal season is likely for southwest Western Australia and southwest Queensland
This outlook is a result of emerging warmer than normal waters in the tropical Pacific Ocean and persistent
warmer than normal waters in the Indian Ocean.
Figure 2-1 – Seasonal Outlook and Median Rainfall – Sep to Nov
Page 5
2.1.3
Issued 19 September 2012 for October to December 2012
Drier conditions likely in the southeast
The national outlook for October 2012 to December 2012 indicates that:

a drier than normal season is likely for large parts of southeast Australia

a wetter than normal season is likely for western Western Australia and southwest Queensland
This outlook is a result of warmer than normal waters in the tropical Pacific Ocean and warmer than normal
waters in the Indian Ocean.
Figure 2-2 – Seasonal Outlook and Median Rainfall – Oct to Dec
2.1.4
Issued 24 October 2012 for November 2012 to January 2013
A wetter season more likely for much of northern and central Australia
The national outlook for November 2012 to January 2013 indicates that:

a wetter than normal season is more likely for large parts of northern and central Australia
This outlook is a mostly a result of warmer than normal waters in the Indian Ocean; warmer than normal
waters in the Pacific Ocean had a lesser impact.
Figure 2-3 – Seasonal Outlook and Median Rainfall – Nov to Jan
Page 6
2.1.5
Issued 21 November 2012 for December 2012 to February 2013
A wetter summer favoured for parts of western and eastern Australia
The national outlook for December 2012 to February 2013 indicates that:

a wetter than normal season is more likely for parts of Western Australia, southeast Queensland and
eastern New South Wales

a drier than normal season is more likely for the northern half of Queensland
This outlook is mostly a result of warmer than normal waters in the Indian Ocean; warmer than normal waters
in the Pacific Ocean had less of an impact.
Figure 2-4 – Seasonal Outlook and Median Rainfall – Dec to Feb
2.1.6
Issued 21 November 2012 for December 2012 to February 2013
A drier summer favoured for parts of eastern Australia
The national outlook for January 2013 to March 2013 indicates that:

a drier than normal season is more likely for parts of eastern Australia
This outlook is a result of warmer than normal waters in the Indian and Pacific Oceans.
Page 7
Figure 2-5 – Seasonal Outlook and Median Rainfall – Jan to Mar
2.1.7
Summary
In summary, with the exception of the seasonal outlooks issued in November 2012, the three-monthly rainfall
outlooks indicated that median rainfall was most likely for the wet season in 2012/2013. The outlook issued in
November 2012 was inconsistent with those issued prior to and after but not did not indicate significantly
higher seasonal rainfall.
Outlooks are summarised in Table 2.1.
Table 2.1 – Summary of Rainfall Outlooks
Issued
Outlook Period
Chance of Exceeding
Median Rainfall
Median Rainfall
in SE Qld
(%)
in Outlook Period
(mm)
Aug 2012
Sep to Nov 2012
50-55
100-200
Sep 2012
Oct to Dec 2012
50
200-300
Oct 2012
Nov 2012 to Jan 2013
55-60
300-400
Nov 2012
Dec 2012 to Feb 2013
70
400-600
Dec 2013
Jan to Mar 2013
45
400-600
Page 8
2.2
Catchment and Dam Status at Event Start
The Antecedent Precipitation Index (API) is an indirect measure of catchment “wetness” and was used at the
start of the Flood Event to derive an estimate of initial loss, which is the amount of rain required before run-off
commences. A relationship derived and used by BoM was used to estimate initial loss, using the following
equation:
IL = 62.5 - 0.4386*API
where:
•
IL = Initial Loss (mm)
•
API = Antecedent Precipitation Index based upon preceding rainfall in the previous 30 days (mm)
•
Minimum API = 5 mm
•
Maximum API = 150 mm
The amount of rain required to fill the dams is added to the estimate of initial loss to estimate the depth of rain
required to operate the dams.
At the start of the week, when the dam status report in Figure 2-6 was compiled by Seqwater, the available
weather forecasts did not indicate the likelihood of the heavy rainfall.
Figure 2-6 – Calculated Antecedent Conditions and Dams Levels at Event Start
At the start of the Event, the North Pine Dam level was about 8% below normal full supply level and it was
estimated that average catchment rainfall of about 110 to 130 mm was required before gate operations were
required.
2.3
Forecasts Preceding Event
Rainfall forecasts developed during the week preceding the Flood Event as a result of the predicted path of
ex-Tropical Cyclone Oswald.
Page 9
In the week preceding the Event,
“Oswald formed in the Gulf of Carpentaria on 21 January, and made landfall that night near
Kowanyama, on the west coast of Cape York Peninsula, as a category 1 system.
It rapidly weakened after landfall and was downgraded to a tropical low on the morning of
22 January. The low then moved near the east coast, being centred off Cooktown on 23 January
and then tracked slowly to the south-southeast just inland from the coast. It was centred near
Townsville on the 24th, became slow-moving in the St. Lawrence-Rockhampton area on the
25th and 26th, and then resumed a southwards track to be centred near Dalby on the 28th. It then
accelerated southwards and moved offshore near Sydney on the 29th before moving out to sea.
Throughout its lifespan, the system brought heavy rainfall, especially in moist easterly to
northeasterly flow on its southern flank. The system was also associated with strong winds, with
numerous sites experiencing gusts in excess of 100 km/h, and coastal storm surges and high
waves, as well as a number of tornadoes, particularly in the Bundaberg area. A storm surge of
around 0.5 metres above normal tide levels was observed at several points along the Queensland
and New South Wales coast, with 0.59 metres above normal tide levels observed at Tweed
Heads, while offshore waves exceeding 12 metres were observed off Coffs Harbour. Significant
coastal erosion and some inundation of foreshore areas were experienced.
There are few close precedents in the last 50 years for the track of Oswald. While a number of
former tropical cyclones have moved far enough south to have significant impacts on New South
Wales, most such systems have either originated over the Coral Sea and not approached the
Queensland coast until south of the Tropic of Capricorn (e.g. Zoe 1974, Nancy 1990), or moved
south from the Gulf of Carpentaria and tracked through western Queensland (e.g. Audrey 1964).”
(Source: Bureau of Meteorology Special Climate Statement 44 – extreme rainfall and flooding in coastal
Queensland and New South Wales).
The persistent southerly track of ex-Tropical Cyclone Oswald contributed to the predictability of the rainfall
which eventuated. In response to this, the Bureau of Meteorology provided the following rainfall forecast on
Thursday, 24/1/2013 at 18:24:
============================
All NWP models are taking the Low further inland than previous model runs, esp
over the southern half of Qld.
Presently the Low lies in the Townsville area tracking S-SE. As the low tracks
further south into the Fitzroy basin, expecting 24-hr rainfall totals of
100-150mm till 4pm Fri. During Sat-Sun the heavy rainfall will extend further
south into the Condamine and Border River areas, with estimates of up to
200-300mm (48-hr total). The Meteorologists have moderate confidence in the NWP
models for Sat-Sun.
SEQ: During Friday increasing rain periods. During Sat-Sun event totals of
200-300mm in the coastal regions (ie: Sunshine Coast), and 150-200mm to areas
west of the range (ie: upper Brisbane Valley) & extending as far south as the NSW
border and into NSW. Bureau flood model run for the Brisbane River using
catchment-wide 250mm over 72 hrs produces areas of minor to moderate flooding in
the Bremer River, although below minor flooding along the Brisbane River. The
hydrological model makes no allowance for dam releases from Wivenhoe, nor any
allowance for the distributed nature of the rainfall.
============================
These forecast rainfall depths formed the basis of scenario runs discussed later.
Page 10
2.4
Lowering of FSL
The Queensland Government issued a gazette under the Water Supply (Safety and Reliability) Act 2008 on
25/1/2013, nominated as the Temporary Full Supply Level (North Pine Dam) Declaration Notice (No 01) 2013.
This declaration was received by the Seqwater Flood Operations Centre at 14:15 on 25/1/2013.
The notice declared a temporary full supply level of EL 38.4 m AHD, which corresponds to approximately 88%
of the permanent full supply volume for North Pine Dam. The temporary full supply level was identified to take
effect from the day of issue and to cease on 31/3/2013.
Seqwater provided contributions to the considerations of temporary full supply level, prior to the issuance of
the above noted declaration. This contribution was in the form of a Departmental Briefing Note prepared on
24/1/2013 and subsequent meetings with Government. This briefing note identified the current dam status,
together with scenario analysis of dam release volumes required based on BoM forecast rainfall estimates
and release rates necessary to achieve the temporary full supply volume.
The current Manual for North Pine Dam does not provide for the operating to meet a declaration of a
temporary full supply level. As a result, operation of North Pine Dam to achieve the temporary full supply level
and to operate the dam while lake levels were less than 39.6 m AHD was enabled by a Revised Interim
Program of the Moreton Resource Operations Plan, revised 25/1/2013.
This interim program included, within the Pine Valleys Water Supply Schemes – Operating Levels for
Infrastructure, the following details, including methodology:
B. Where the Minister declares by gazette notice a temporary full supply level for North Pine Dam
under the Water Supply (Safety and Reliability) Act 2008 and the NPD Manual does not contain
operational procedures that apply to releases of water to achieve a declared temporary full supply
level, Seqwater will, subject to the operational constraints specified below, make releases from
North Pine Dam necessary to:
(a) initially reduce the lake level to the temporary full supply level from the date specified in the
gazette notice; and
(b) operationally maintain storage levels, in the absence of a flood event, at or close to the
temporary full supply level during the period of operation of the temporary full supply level.
The releases specified in (a) and (b) will only be made:
(i) after Local Authorities have been notified by Seqwater of the proposed releases and
Seqwater has confirmed that Youngs Crossing has been closed to traffic; and
(ii) other than in exceptional circumstances, the releases from North Pine Dam shall:
•
not exceed a peak rate of 300m³/s; and
•
not cause the flow at Youngs Crossing to exceed an estimated flow rate of 900m³/s.
If, after releases have commenced, a flood event (within the meaning of the NPD Manual) is
declared, the North Pine Dam will be operated in accordance with the NPD Manual. Once the
flood event has ended, the operational releases referred to in paragraph (b) above shall be made.
2.5
Forecast Flows at Event Commencement
In compliance with the reporting requirements of the Water Supply (Safety and Reliability) Act 2008, forecast
inflows to the dams and outflows from the dams are detailed in this part. With the high uncertainty of rainfall
estimates, the forecasting of flow conditions at event commencement should be taken to represent the flow
conditions based on the corresponding rainfall scenario only.
Section 5 of this report details the model runs performed during the Flood Event and Appendix D contains full
details of the model runs. Of these, model scenarios one to eight inclusive represent the modeling of a range
Page 11
of rainfall depths and intensities and considering a range of initial catchment conditions. The forecast peak
inflow, total inflow volume and peak outflow are listed in Table 2.2. Factors such as realised rainfall, spatial
and temporal variability and catchment conditions strongly influence a flood event as it occurs; hence, forecast
flows at event commencement provide indicative guidance of possible flood conditions.
Table 2.2 – Inflow and Outflow Scenarios at Event Commencement
Model Scenario
Inflow
Outflow
1
87 m3/s
0 m3/s
18,150 ML
2
87 m3/s
0 m3/s
14,650 ML
3
222 m3/s
278 m3/s
49,040 ML
4
222 m3/s
278 m3/s
42,160 ML
5
356 m3/s
412 m3/s
81,870 ML
6
356 m3/s
412 m3/s
73,500 ML
7
423 m3/s
466 m3/s
62,140 ML
8
423 m3/s
466 m3/s
53,290 ML
Page 12
3.
EVENT READINESS
3.1
Preparedness
3.1.1
Statement of Preparedness
In accordance with Section 2.3 of the Manual of Operational Procedures for Flood Mitigation at North Pine
Dam (Revision 7), Seqwater must provide a detailed report to the Chief Executive by 30 September each year
identifying the state of preparedness of the Dams, the Flood Operations Centre and the Flood Forecasting
System to manage flood events in accordance with the Manual.
This statement was provided to the Director General of DEWS by the Chief Executive Officer of Seqwater on
28/9/2012 (Seqwater, 2012). This statement included, in accordance with Section of the Manual:

The training of personnel responsible for dam operations, in accordance with Section 2.8 of the Manual

The state of the flood forecasting system, in accordance with Section 2.9 of the Manual

The state of communications equipment between the Flood Operations Centre and the dams, in
accordance with Section 2.11 of the Manual.
3.1.2
Approved Engineers
The Statement of Preparedness discussed in the above section contains the Schedule of Authority (1 October
2012 to 1 October 2013) listing authorised Senior Flood Operations Engineers and Flood Operations
Engineers. Subsequent to this statement, on 24/12/2012 the General Manager Office of Water Supply
Regulator (delegate of the Chief Executive) authorised the following changes to the Schedule of Authority:

Inclusion of two additional Flood Operations Engineers and one Senior Flood Operations Engineer

Promotion of one Flood Operations Engineer to Senior Flood Operations Engineer.
Following these changes, the authority comprised five Senior Flood Operations Engineers and five Flood
Operations Engineers. Senior Flood Engineers were registered professional engineers (RPEQ) at the time of
the event and held an appropriate engineering qualification. Personnel responsible for flood operations
undertook training prior to the Flood Event as required by the Chief Executive.
3.1.3
Communications Equipment
The following methods of communication between dam sites and the Flood Operation Centre were confirmed
as working prior to the flood event:

Landline telephone

Mobile telephones

Facsimile

Email

Radio network

Satellite phones
3.1.4
Confirmed Dam Release Infrastructure Status
All five radial gates at North Pine Dam were operational prior to the commencement of the Flood Event.
3.2
Mobilisation
As discussed in Section 2.3 of this report, rainfall forecasts associated with ex-Tropical Cyclone Oswald were
provided to the Flood Operations Centre on 24/1/2013. In response to these forecasts and the declaration of
a temporary full supply level for North Pine Dam of immediate effect, the Flood Operations Centre was
mobilised on 25/1/2013 at 12:00.
Page 13
3.3
Staffing at the Flood Operations Centre
As soon as mobilisation occurred, full-time staffing commenced at the Flood Operations Centre, with at least
one Senior Flood Operations Engineer, one Flood Operations Engineer and at least one Flood Officer
present.
Staffing of the Flood Operations Centre continued on this basis until event de-mobilisation at 16:00 on
4/2/2013.
3.4
Staffing at Dams
Staffing at North Pine Dam commenced at 7:00 on 25/1/2013, prior to releases commencing to achieve the
temporary full supply level.
Page 14
4.
FLOOD EVENT DATA
4.1
Introduction
This section of the report describes the data collected during the Flood Event and provides summaries of
relevant information.
4.2
Monitoring Network
Seqwater maintains a real-time network to monitor rainfall and water levels in the dams’ catchments and to
provide sufficient information that is both accurate and timely to allow informed decision making.
Field stations consisting of rainfall and water level sensors communicate data to the Flood Operations Centre
on an event reporting basis via radio. More than one sensor may be located at an individual field station.
Water level gauges are often located at Department of Natural Resources and Mines (DNRM) gauging
stations. DRNM is responsible for the maintenance of their water level gauges and Seqwater for the
communications equipment.
The Seqwater network is part of a larger network in South East Queensland which consists of stations
operated by other agencies such as Councils and BoM. Data from stations in the network is shared freely
between co-operating agencies which use the Bureau’s freely supplied software package, Enviromon, to
collect, display and archive data from the network.
Rainfall gauges consist of a standard tipping bucket varying in bucket size from 0.2 to 1 mm. At a rainfall
gauge, an event is defined as the tip of the bucket, with bucket volumes calibrated to 1 mm per tip.
Water level or river gauges vary in type and model but include shaft encoders, wet and dry pressure
transducers and radars. At water level gauges, an event
is defined as an incremental increase or decrease in
water level, the increment being 10, 20 or 50 mm
depending on site characteristics such as tidal influence
and the absolute measurement range of the sensor.
When an event is triggered at a gauge, data is
transmitted via VHF radio through a series of radio
repeaters to the Flood Operations Centre and other data
collection centres. Each signal has a unique
identification number which is relayed to a computer
hardware platform serial port via a decoder when it
arrives at the Flood Operations Centre base station. The
data is then time stamped, read, decoded, filtered and
validated before being stored in the Flood Operations
Centre’s Enviromon database. The same data is also fed
into Enviromon via IP directly from BoM as a backup.
Figure 4-1 – Enviromon
The Enviromon software allows filtered gauge data to be viewed in maps, tables or graphical format.
Erroneous data can be identified and marked as suspect. This means that it is not used in modelling but
retained in the database.
The combination of field stations, rainfall gauges and water level gauges, radio network and data collection
software is referred to as an ALERT system. ALERT has become a standard for flood warning systems in
Australia and the United States of America, and is widely used by BoM and other flood warning agencies
throughout the world.
The ALERT system is the primary source of data for real time modelling of flows in Seqwater catchments.
Page 15
4.3
Seqwater’s ALERT Network
The ALERT network currently consists of 355 rain sensors and 245 water level sensors at field stations
throughout South East Queensland. Of this network, Seqwater operates 112 rainfall sensors and 80 water
level sensors.
Manual gauge board readings, taken at most dams including Wivenhoe, Somerset and North Pine dams to
confirm the ALERT data, form the basis for gate operations.
Table 4.1 – Seqwater ALERT Stations
Rain
River
Rain
River
ALERT
ALERT
ID
ID
Name
ALERT
ALERT
ID
ID
Name
6580
6581
ADAMS BRIDGE ALERT
6633
6634
LYONS BRIDGE ALERT-P
6654
AMBERLEY (DEWS) AL
6626
6627
MAROON DAM ALERT
6651
6652
GREENS RD
6449
6450
6555
6558
ATKINSON DAM ALERT
6754
6755
BAROON BOAT RAMP ALERT
6609
5569
BAROON DAM INTAKE ALERT
6624
5571
5572
BAROON DAM TW ALERT
6601
MT BINGA ALERT
6711
6712
BAXTERS CREEK ALERT
6619
MT CASTLE ALERT
6660
BERRYS LAGOON ALERT-B
1911
MT COTTON WEST ALERT
6657
BILL GUNN DAM ALERT
6751
BLACKBUTT ALERT
6680
5566
6656
6603
MAROOCHY INTAKE WEIR
ALERT
MOGGILL ALERT-P
MONSILDALE ALERT
6625
6752
MOOGERAH DAM HW ALERT
MT CROSBY ALERT
MT GLORIOUS ALERT-P
6520
6521
BOAT MOUNTAIN ALERT
6663
6664
BORUMBA DAM HW ALERT
6701
MT MEE ALERT-B
6748
6749
BRISBANE CITY ALERT
6690
MT MEE ALERT-P
5363
5364
BROMELTON DAM ALERT
6620
MT NEBO ALERT
6616
BRYDEN ALERT
6612
MT STANLEY ALERT
1913
BURBANK ALERT
5360
5361
NINDOOINBAH DAM ALERT
BURTONS BRIDGE ALERT
6760
6761
NORTH PINE DAM ALERT
CABOONBAH ALERT
6759
6762
NORTH PINE DAM ALERT-B
6756
6574
6720
MT KILCOY WEIR ALERT
6940
6941
CEDAR POCKET DAM ALERT
6621
5580
5581
COOLOOLABIN DAM ALERT
6568
6569
O'REILLY'S WEIR ALERT
6542
6543
COOYAR CREEK ALERT
6775
6776
PEACHESTER ALERT
6523
6524
CRESSBROOK DAM ALERT
5583
5584
POONA DAM AL
CROWS NEST ALERT
1909
PRIESTDALE ALERT
6596
NUKINENDA ALERT
6946
6947
DAGUN POCKET ALERT
6622
RAYNBIRD CREEK ALERT
1987
1988
DAYBORO WWTP ALERT
6611
REDBANK CREEK ALERT
6708
6709
DEVON HILLS ALERT
6631
Page 16
RIFLE RANGE ROAD ALERT
Rain
River
ALERT
ALERT
ID
ID
Name
6769
6770
DRAPERS CROSSING ALERT
1907
1533
1534
ENOGGERA DAM ALERT
6553
6554
ROSENTRETERS BRIDGE AL
ESKDALE ALERT
6733
6734
ROSEWOOD ALERT
EWEN MADDOCK DAM ALERT
6778
FERRIS KNOB ALERT
6559
6560
SAVAGES CROSSING ALERT
GATTON ALERT
6583
6584
SHOWGROUND WEIR ALERT
GLEN ESK ALERT
6590
6591
SOMERSET DAM HW ALERT-B
6593
6594
SOMERSET DAM HW ALERT-P
6605
5404
5405
6714
6577
6578
6618
Rain
River
ALERT
ALERT
ID
ID
Name
ROCHEDALE SOUTH ALERT
SAMFORD ALERT
6556
6557
GLENORE GROVE ALERT
1718
1717
GOLD CK RESERVOIR ALERT
6595
SOMERSET DAM HW ALERT-P2
6517
6518
GREGOR CK ALERT-B
6645
SPLITYARD CREEK DAM AL
6514
6515
GREGOR CK ALERT-P
6529
ST AUBYNS ALERT
6571
6572
HARRISVILLE ALERT
6669
SUNDAY CREEK ALERT
HAZELDEAN ALERT
6623
TAROME ALERT-P
6527
HELIDON ALERT
6565
2226
HINZE DAM ALERT-B
6615
THORNTON ALERT
JIMNA ALERT
6604
TOOGOOLAWAH ALERT
6613
6526
6608
6566
6730
6731
JINDALEE ALERT
6661
6562
6563
KALBAR WEIR ALERT
6598
TOOWOOMBA ALERT
6757
KHOLO BRIDGE ALERT
6602
TOP OF BRISBANE ALERT
KILCOY ALERT
6550
6600
6720
KILCOY CK ALERT
6662
TENTHILL ALERT
TOOHILLS CROSSING ALERT
6551
FIVE MILE BR ALERT
6743
WALLOON DEWS AL
5587
WAPPA DAM ALERT
6671
KINGHAM AKERT
5586
6610
KLUVERS LOOKOUT ALERT
6739
WASHPOOL ALERT
1991
KOBBLE CK ALERT
6716
WEST BELLTHORPE ALERT
6736
6737
KUSS ROAD ALERT
6606
WEST WOODBINE ALERT
6658
6659
6614
WESTVALE ALERT
6766
6767
6937
6938
1730
1729
LAKE MANCHESTER ALERT
1902
1903
LESLIE HARRISON DAM AL
6607
6717
6617
6718
LAKE CLARENDON DAM
ALERT
LAKE KURWONGBAH ALERT
LAKE MACDONALD DAM
ALERT
6747
6774
6636
WHYTE ISLAND ALERT
WILSONS PEAK ALERT-P
6637
WIVENHOE DAM HW ALERT-B
6638
WIVENHOE DAM HW ALERT-B2
LINDFIELD ALERT
6643
6644
WIVENHOE DAM TW ALERT-P
LINVILLE ALERT
6702
6703
WOODFORD ALERT-B
LITTLE EGYPT ALERT
6705
6706
WOODFORD ALERT-P
Page 17
Rain
River
Rain
River
ALERT
ALERT
ID
ID
Name
ALERT
ALERT
ID
ID
Name
2220
2223
LITTLE NERANG DAM ALERT
5366
5367
WYARALONG DAM ALERT
6646
6647
LOWOOD PUMP STN ALERT-B
6540
YARRAMAN ALERT
All available ALERT rainfall stations are shown in Figure 4-2 and Seqwater owned water river level stations
shown in Figure 4-3.
Page 18
Figure 4-2 – ALERT Rainfall Network in SE Qld
Page 19
Figure 4-3 – Seqwater ALERT River Network in SE Qld
Page 20
4.4
Seqwater’s ALERT Network Performance
At the start of the Flood Event, six ALERT rain sensors and three ALERT water level sensors were Out of
Action (OOA).
Table 4.2 – Sensors OOA at Event Start
Rain
River
ALERT ID
ALERT ID
Name
6555
6558
ATKINSON DAM ALERT
6562
KALBAR WEIR ALERT
6617
LITTLE EGYPT ALERT
1907
ROCHEDALE SOUTH ALERT
6702
WOODFORD ALERT-B
5571
BAROON DAM TW ALERT
6767
LAKE KURWONGBAH ALERT
6938
LAKE MACDONALD DAM ALERT
In the week prior to the Flood Event, effort was made to repair some of these sensors. Kalbar Weir rain
gauge was serviced, the tail water river sensor was replaced and gauge boards were installed at the head
water. Lake Kurwongbah (Sideling Creek Dam) was visited and the radio communications were repaired so
that the data could once again transmit. In addition, the batteries at Leslie Harrison Dam were sending out
low voltage warnings. This was rectified before it created any faults for the site.
When Lake Macdonald failed on 26/1/2013, the site was visited and a new river sensor was installed.
On 26/1/2013, Lowood was also visited, as communications with Lowood Pump Station failed and the site
was visited. It is suspected that that the solar panel was not receiving enough light for a period of time that
flattened the battery. The site came back online, possibly after the sun recharged the battery. The station
was switched to mains to prevent further issues.
On 31/1/2013, sites in the Logan and Warrill catchments were investigated for flood damage. On site repairs
were carried out at:
1.
Bromelton Dam – cables in rain gauge had come loose, possibly due to strong winds
2.
Warrill Ck at Greens Rd – power failure, connected new power pack
At the conclusion of the Flood Event, six rain sensors and 11 river sensors were not operating correctly.
Some rain gauges appeared to under report. They all seemed to be elevated exposed gauges. It is
suspected that either the wind played a factor or there was less rainfall in these areas.
Table 4.3 – Failed Sensors during Event
Rain
River
ALERT ID
ALERT ID
Name
Issue
6748
BRISBANE CITY ALERT
Stopped working
6714
FERRIS KNOB ALERT
Stopped working
LOWOOD PUMP STN ALERT-B
Stopped working
6646
6647
Page 21
Rain
River
ALERT ID
ALERT ID
Name
Issue
6760
NORTH PINE DAM ALERT
Under reported but since serviced
1730
LAKE MANCHESTER ALERT
Under reported
6610
KLUVERS LOOKOUT ALERT
Under reported
5367
WYARALONG DAM ALERT
Erroneous water levels
6662
TOOHILLS CROSSING ALERT
6563
KALBAR WEIR ALERT
6566
TENTHILL ALERT
6518
GREGOR CK ALERT-B
1988
DAYBORO WWTP ALERT
6569
O'REILLY'S WEIR ALERT
6659
LAKE CLARENDON DAM ALERT
6652
GREENS RD ALERT
6634
LYONS BRIDGE ALERT
Erroneous reports on rising limb
Overall, the level of available gauges and the number which failed during the Flood Event is considered
reasonable and sensors which were OOA at the start of the Flood Event or which failed during the Flood
Event had no measurable impact on dam operations.
4.5
Forecast Rainfall
Forecast rainfall is sourced from BoM for consideration in estimating the potential timing and magnitude of
flood flows in various catchments.
Seqwater and BoM have clear understanding of the uncertainty of forecast rainfall in terms of spatial and
temporal distributions. Section 4.3 of the Manual also recognises this uncertainty and advises that
predictability of forecast rainfall will vary from event to event and may depend upon the nature of the
underlying synoptic conditions causing or likely to cause the rainfall.
Generally, the longer the forecast lead times, the higher the degree of uncertainty in the forecast.
Forecast rainfall from BoM is primarily provided via:

24-hour Quantitative Precipitation Forecasts (QPF)

PME (Poor Man’s Ensemble) gridded rainfall.
Additional BoM information is also sourced from:

interactive weather and wave forecast rainfall maps (based on ACCESS Model)

weather warnings

weather radar

regular briefings between FOC and BoM staff during the Flood Event.
The QPFs are provided to the FOC by the senior duty meteorologist in the BoM’s Regional Forecasting
Centre twice daily at approximately 10:00 and 16:00 and provide rainfall depths for North Pine, Somerset and
Wivenhoe catchments only. They do not contain any information for other Seqwater catchments or for other
areas which may be impacted by heavy rainfall.
Page 22
Table 4.4 – QPF 24 Hour Forecasts
300
60
20
20
Lower
15
20
100
150
150
150
200
40
10
10
29/01/2013 16:00
250
29/01/2013 10:00
250
28/01/2013 16:00
250
28/01/2013 10:00
150
27/01/2013 16:00
20
27/01/2013 10:00
15
26/01/2013 16:00
Upper
26/01/2013 10:00
24 Hour QPF Forecast to
25/01/2013 16:00
Range
25/01/2013 10:00
Catchment
North Pine Dam
The Poor Man’s Ensemble (PME) provides three-hourly gridded rainfall forecast fields with an outlook to eight
days generated automatically by weather forecast models. Up to eight models are combined to produce the
rainfall forecasts using a weighting method. Seqwater subscribes to the BoM service and forecast rainfall
grids are downloaded in FEWS twice daily at approximately 9:00 and 21:00.
Further information about forecast rainfall can be found at:
http://www.bom.gov.au/watl/about/about-forecast-rainfall.shtml#models
Table 4.5 – PME 24 Hour Forecasts
4.6
69
139
98
17
29/01/2013 16:00
119
29/01/2013 10:00
113
28/01/2013 16:00
26/01/2013 16:00
26/01/2013 10:00
55
28/01/2013 10:00
24
27/01/2013 16:00
21
27/01/2013 10:00
North Pine Dam
25/01/2013 16:00
24 Hour PME Forecast to
25/01/2013 10:00
Catchment
10
Daily Rainfall
The following rainfall tables and maps show the daily rainfall recorded in the Brisbane River Basin during the
Flood Event. The tables are sources from the Enviromon system, while the maps are from the FEWS data
display and modelling system.
Page 23
Table 4.6 – Daily Totals for Pine Rivers Basin (Source: Enviromon)
24 Hours to 09:00 Ending
BoM
No
Station
540138
Mt Glorious AL-P
6
32
167
182
406
22
0
9
823
540444
Cedar Ck Rd AL
3
30
101
84
291
17
0
6
532
540060
Samford AL
1
30
75
81
257
13
0
9
465
540416
Samford Village AL
0
21
69
84
261
6
0
3
445
540418
Clear Mountain AL
1
30
67
44
104
7
0
17
270
540205
Drapers Xing AL
1
26
59
73
220
4
0
7
389
540415
Cash's Crossing AL
0
26
51
62
213
4
0
7
363
540414
Normanby Way AL
0
33
49
55
150
8
1
10
306
540168
Kluvers Lkt AL
0
20
100
97
137
5
1
23
383
540409
Laceys Ck AL
1
20
92
122
203
7
0
4
449
540545
Raynbird Ck AL
2
29
118
168
311
10
0
17
655
540189
Baxters Ck AL
0
22
88
120
264
5
0
5
504
540410
Dayboro AL
0
21
95
132
278
9
0
6
541
540484
Dayboro WWTP AL
0
29
71
118
261
6
0
4
489
540447
Mt Samson Rd AL
1
36
74
114
268
5
0
8
506
540202
North Pine Dam AL
1
46
17
20
36
1
0
0
121
540277
North Pine Dam AL-B
1
46
17
20
39
1
0
0
124
540411
Browns Ck AL
0
23
54
91
189
5
0
10
371
540204
Lake Kurwongbah AL
0
0
45
53
164
2
0
0
264
540412
Youngs Crossing AL
1
70
49
51
165
2
0
1
339
540439
Lawnton AL
1
59
45
45
142
4
1
2
299
540413
John Bray Park AL
1
39
44
60
165
6
2
13
330
540417
Murrumba Downs AL
0
36
48
57
160
3
0
8
312
540445
Lipscombe Rd AL
0
25
32
47
140
4
0
1
249
540246
Mt Mee AL-B
1
28
145
190
188
5
0
10
567
540185
Mt Mee AL-P
3
27
145
190
187
5
0
11
568
540358
Moorina AL
1
24
91
88
179
9
0
5
397
540242
Burpengary (Dale St)
0
17
53
76
144
2
0
6
299
540245
Burpengary (Rowley
Rd)
5
20
67
83
142
1
0
6
324
040980
Deception Bay AL
0
18
32
49
116
2
0
2
219
540241
Round Mt Res AL
1
20
54
85
134
5
0
9
308
Page 24
31/01
30/01
29/01
28/01
27/01
26/01
25/01
24/01
Total
24 Hours to 09:00 Ending
BoM
No
Station
540244
Wamuran AL
3
22
74
109
149
5
0
6
368
540357
Upper Caboolture AL
0
17
89
94
183
9
0
5
396
540243
Caboolture AL
0
18
72
111
148
3
0
7
360
040979
Morayfield AL
1
15
65
84
155
2
0
14
336
040978
Bribie Island AL
0
18
24
48
134
1
0
4
229
Page 25
31/01
30/01
29/01
28/01
27/01
26/01
25/01
24/01
Total
Figure 4-4 – Daily Rainfall (mm) 24 hours to 09:00 24/01/2013 (Source: FEWS)
In the 24 hours to 9:00 24/1/2013, only light rain was recorded in South East Queensland with the highest
totals around 25 mm in the headwaters of the Laidley Creek, Bremer River, Warrill Creek and Logan River.
Page 26
In the 24 hours to 9:00 25/1/2013, rainfall in South East Queensland was widespread with heavy rainfall, up to
120 mm, recorded in Sunshine Coast catchments. Totals were generally less than 10 mm in the Brisbane
River Basin with higher totals, up to 70 mm, in the Pine Rivers Basin.
Page 27
In the 24 hours to 9:00 26/1/2013, rainfall in South East Queensland was again widespread with heavy
rainfall, up to 170mm, recorded in elevated areas between Mt Mee and Mt Glorious, around Mt Castle and in
the headwaters of the Nerang River.
Totals in the Brisbane River Basin varied greatly from 15 to 167 mm while rain in the Pine Rivers Basin was
generally more uniform with totals from 67 to 118 mm.
Page 28
In the 24 hours to 9:00 27/1/2013, the influence of the southward movement of ex-Tropical Cyclone Oswald
became evident with heavy rainfall in South East Queensland widespread, with the highest totals again
recorded in ridge between the upper Brisbane, Stanley and Mary Rivers, around Mt Castle in the headwaters
of Laidley Ck, the Bremer River and Warrill Creek and in the headwaters of the Nerang River.
Totals in the Brisbane River Basin were reasonably uniform in the areas upstream of Somerset and Wivenhoe
Dams with totals up to 200 mm. The area immediately to the west of Mt Glorious received lower falls than the
rest of the catchment with totals only up to 50 mm. In catchments downstream of Wivenhoe rainfall, totals
varied from 40 to 170 mm. Rainfall in the Pine Rivers Basin was generally more uniform with totals from
100 to 170 mm.
Page 29
In the 24 hours to 9:00 28/1/2013, ex-Tropical Cyclone Oswald had largely moved past the Brisbane area and
the highest rainfall tended to be in coastal areas and in catchments downstream of Wivenhoe Dam. High
rainfall was recorded in elevated areas between the North Pine River and Mid Brisbane where 447 mm was
recorded at Mt Nebo, again around Mt Castle (709 mm) in the headwaters of Laidley Ck, the Bremer River
and Warrill Creek. Heavy rainfall was also widespread in the Logan and Nerang Rivers (Upper Springbrook
745 mm) with daily totals up to 350 mm.
Page 30
In the 24 hours to 9:00 29/01/2013, the highest rainfall was recorded in the headwaters of the Nerang River
where Upper Springbrook recorded another 377 mm. Elsewhere totals in the Brisbane and Pine River Basin
were generally less than 20 mm although isolated higher totals were recorded in elevated areas.
Page 31
Figure 4-10 – Rainfall (mm) 5 Days to 09:00 29/01/2013 (Source: FEWS)
The map presented in Figure 4.10 shows the rainfall totals in the five days to 9:00 29/1/2013. The different
scale from the previous maps should be noted.
There was a strong orographic influence on the recorded rainfalls during the period with the highest totals in
elevated areas. Highest totals include Cooloolabin Dam 793 mm, Baroon Dam 866 mm, Mt Glorious 808 mm,
Mt Castle 1,219 mm, Upper Springbrook 1,473 mm.
Page 32
4.7
Average Catchment Rainfall
In FEWS, the average rainfall for each sub-catchment is determined by fitting a gridded surface to the
recorded station rainfalls and using a polygon outline of each sub-catchment to determine the average rainfall
for the sub-catchment from the grid.
Figure 4-11 – Catchment Average Rainfall (mm) for 5 Days to 09:00 29/01/2013 (Source: FEWS)
Figure 4-11 shows the average catchment rainfall over the five days to 9:00 29/1/2013. Highest totals were
recorded in the Sunshine Coast catchments and in elevated catchments in the south and south-west.
Page 33
4.8
Catchment Temporal Patterns
The average hourly rainfall for the North Pine Dam catchment is determined by applying a weighting to the
rainfall depth at each available station within the sub-catchment. This is calculated during the modelling
process.
Figure 4-12 – Average Catchment Rainfall – Catchment to North Pine Dam
As indicated in Figure 4-12, the period of heaviest rain in the North Pine catchment commenced in the early
hours of 27/1/2013 and continued until that evening.
4.9
Gauging Station Hydrographs
The following figure presents the hydrographs of the water levels recorded at Seqwater owned ALERT
gauging stations upstream of North Pine Dam through the Event. Water level data available at other ALERT
stations in the basin operated by other agencies is not reported here. The four digit ALERT ID is shown as the
station identifier.
Page 34
Figure 4-13 – Hydrographs – Inflows to North Pine Dam
The primary water level station at Baxters Creek reported satisfactorily throughout the event but there were
problems with the water level sensors and/or communications systems at Dayboro WWTP and Kobble Creek
gauge sites.
4.10
Dam Water Levels, Gate Settings and Outflows
The water levels and outflows for North Pine Dam are presented in the Figure 4.14 and tabulated in
Appendix D.
Page 35
Figure 4-14 – North Pine Dam Water Level and Outflows
The maximum lake level in North Pine Dam was 39.80 m AHD at 21:00 on 27/1/2013 and the peak of the
outflow 834 m3/s occurred at 22:00 on 27/1/2013.
The ALERT water level sensors matched the manual gauge board readings throughout the Flood Event.
Page 36
5.
FLOOD MODELLING
5.1
Introduction
This section of the report describes the flood modelling systems used to estimate flows in the North Pine
catchment during the Event. It also details the model runs and results generated at strategic times throughout
the Event.
5.2
Modelling Systems
Three hydrologic modelling systems were available in the FOC to generate estimates of inflows:

System 1: The Enviromon data collection system is linked directly to the URBS Control Centre which
contains URBS hydrological models of all Seqwater catchments. The URBS Control Centre software
allows the user to modify model parameters, add forecast rainfall and run the hydrologic models for the
North Pine Dam catchment. Output from the URBS models is then input into a Gate Operations Module.

System 2: Data from Enviromon is regularly fed into FEWS every 15 minutes. Within FEWS, URBS
hydrological models can be run. The implementation of FEWS as a modelling system at Seqwater is still
undergoing implementation, and this Flood Event provided an opportunity to test the system.

System 3: A legacy modelling system FLOOD, consisting of a data collection module Flood-Col and a
modelling module Flood-Ops, was also available but was not required for the duration of the Flood
Event.
The FEWS modelling system is a system currently under development for application by Seqwater. Further
information on the testing of the FEWS system is contained in the Wivenhoe Somerset Flood Event Report.
FEWS was only used for data display for the North Pine Flood Event.
5.2.1
The URBS Hydrologic Model
The conceptual run-off routing model URBS (Carroll 2004) was used to estimate inflows into the dams and in
rivers and streams in downstream areas. URBS is a computer based, hydrologic modelling program that
enables the simulation of catchment storage and run-off response by a network of conceptual storages
representing the stream network and reservoirs.
The URBS split model mode, used during the Flood Event, simulates the catchment and channel routing in
each sub-area and calculates their affects separately. First, the excess rainfall on a sub-area is routed to the
creek channel. The inflow from the sub-area into the channel is assumed to occur at the centroid of the subarea. The lag of the sub-area storage is assumed proportional to the square root of the sub-area area. Next,
the inflow is routed along a channel reach using a linear Muskingum method, whose lag time is assumed
proportional to the length (or derivative) of the reach.
The influence of drowned reaches within reservoirs is taken into account by reducing the relative travel time in
the affected reaches. In the URBS model, this is achieved by using a reach length factor; in this case 0.5,
effectively halving the travel in drowned reaches. In addition, reservoir areas are represented as impervious,
increasing the volume of run-off from those parts of the catchment.
Page 37
Figure 5-1 – URBS Model of North Pine catchment
The URBS model is widely used by BoM for flood forecasting throughout Australia.
In its current operational form, the URBS model only generates surface run-off and does not include any
allowance for baseflow. However, allowances for baseflow can be included in the Gate Operations Module.
5.2.2
URBS Control Centre
The URBS Control Centre facilitates the extraction of data from Enviromon, processing of this data and
running of the URBS hydrologic models. Rainfall and water level data is extracted from Enviromon and
produced in URBS compatible format. A virtual rainfall time series is generated for each sub-area in the
model using a triangulation technique similar to Thiessen polygons. The process is interactive and allows
users to ignore any erroneous or suspect rainfall data.
URBS hydrologic models are run via the URBS Control Centre which allows users to interactively modify loss
and routing parameters to match the recorded gauge height data with user defined allowances for forecast
rainfall.
Figure 5-2 depicts the URBS Control Centre interface used during this Flood Event.
Page 38
Figure 5-2 – URBS Control Centre
5.2.3
FLOOD Modelling System
The FLOOD modelling system is a legacy system that was developed in the mid-1990s specifically for flood
operations at Somerset Dam, Wivenhoe Dam and North Pine Dam. The system contains a data collection
system, Flood-Col, based on an early, pre-windows version of Enviromon, and a modelling system, FloodOps, that uses a suite of WT42 hydrologic models. This system has been retained as a backup modelling
system; however it was not used during this Flood Event.
5.2.4
The Gate Operations Module
The modelled flows derived using the URBS models are imported into a Gate Operations Module, a
customised spreadsheet, to determine appropriate gate settings at North Pine Dam and to estimate the
downstream flows resulting from releases from the dam. The Gate Operations Module performs many
functions including:

automated importation of modelling inflows

routing of inflows through the storage using level pool routing techniques

comparison of modelled water level verses recorded water levels at North Pine Dam

adjustments to baseflow parameters

displaying a host of useful statistics and information for the Duty Flood Engineers.
Within the Gate Operations Module, inflows can be scaled and allowances for baseflow are made to ensure
that the volume of run-off into dams matches the recorded water levels.
Users are able to check the performance of the models through a series of graphs and tables and make
adjustments to strategy to cater for the forecast rainfall assumptions made in the hydrologic modelling
process.
Instances of the Gate Operations Module are saved regularly during the Flood Event, especially when there
are significant changes in forecast rainfall, inflows and/or operating strategies.
Page 39
5.3
Model Runs With and Without Forecast Rainfall
Of the modelling systems available during the Flood Event, System 1 was adopted as the primary modelling
system; that is, data was collected via Enviromon, inflows were modelled using the URBS Control Centre and
the Gate Operations Module was used to make decisions on releases from North Pine Dam.
Seventy (70) model runs were archived preceding and throughout the Flood Event that either included or
excluded forecast rainfall. Of these, the following breakdown of scenarios applied:

Eleven scenarios were assessed prior to the Flood Event. These are all forecast rainfall (FR) scenarios.

Fifty-six scenarios were run during the Flood Event with no forecast rainfall (NR). These model runs
consider rainfall once it has been recorded (i.e. actual rainfall that has occurred).

One mid-event forecast rainfall scenario was run including forecast rainfall, at 16:00 on 27/1/2013.

Two operational scenarios were maintained during the Flood Event; an operational case with no forecast
case (NR) and an operational case with forecast rainfall (FR).
The forecast rainfall scenarios (FR) represent the ‘what if’ scenarios, whereas the no additional rainfall
scenarios (NR) represent the ‘rain on the ground’ scenario. Together, the two rainfall scenarios help inform the
Duty Engineer of the possible evolution of the Flood Event and provide assistance in selecting a strategy.
Although only 70 runs were archived throughout this Flood Event, a model run was generally undertaken
every hour while rainfall was occurring, high rainfall forecasts were issued and/or prior to inflows peaking.
Archiving of a model run was only undertaken when any of the Duty Engineers deemed the situation to have
changed significantly since the last archived model run, or to capture a particular scenario for reference. The
frequency of model archiving throughout this Flood Event increased during periods of high rainfall and when
high rainfall forecasts were provided.
5.3.1
Presentation of a Selection of Modelled Scenarios
Due to the relatively small catchment size, the model performance of the North Pine Dam system is highly
dependent on rainfall as it occurs within the catchment. Model scenarios are generally run on an hourly basis
during periods of rainfall, with forecast rainfall scenarios assessed at key decision points within the Flood
Event to inform future operating strategies.
For the Flood Event, the key decision point in time that directed flood operations occurred at 16:00 on
27/1/2013. The dam operating scenarios at this time are discussed in detail in Section 6 of this report. At this
time, BoM rainfall forecasts received verbally were for 100 mm of additional rainfall in the near coastal over
the next 12 hours. Using this information, a forecast rainfall scenario was developed with results compared to
the comparable scenario with no forecast rainfall.
A comparison is shown in Figure 5-3, showing this no rain scenario and the forecast rainfall scenario
modelled inflow hydrographs to North Pine Dam at this time. Also shown on this figure is the final URBS
inflow series derived at the conclusion of the Flood Event.
Page 40
Figure 5-3 – Modelled Inflow to North Pine Dam as at approximately 17:00 27/1/2013
An operating plan for North Pine Dam was developed at 16:00 27/1/2013 considering the dam inflows
predicted by both the forecast and no forecast rainfall scenarios.
Page 41
Blank page
Page 42
6.
DAM OPERATIONS
This section details the operations conducted at North Pine Dam in the Flood Event. Information presented is
as it was established at the time in the event with rounding of values applied to reflect the uncertainty of
estimates, particularly estimates of dam inflow rates. Changes in release rates from the dam occur
progressively dependent on the magnitude of release rate change, lake level and other flood conditions. At
their most rapid, gate movements were conducted as per the minimum intervals for radial gate operations
outlined in the Manual.
6.1
Strategy Timeline and Selection
The progression of North Pine Dam operating strategies as applied during the Flood Event is summarised in
Table 6.1. The information timeline summarised in Table 6.1 is discussed in further details in the following
sub-sections. Note the listed timing of situation reports in this table is generalised to 7:00 and 19:00 to
capture event chronology and is not intended to account for the specific timing of each report.
The Flood Event for the North Pine Dam system can be broadly grouped into the following three phases to
assist in event operational commentary. These groupings were assigned after the Flood Event to aid in the
reporting discussion.

Phase 1: Reduction to Temporary Full Supply Level 23/1/2013 9:00 to 26/1/2013 8:15 – Dam
releases to enact the Temporary Full Supply Level (North Pine Dam) Declaration Notice (No 01) 2013.

Phase 2: Operational Releases 26/1/2013 20:00 to 27/1/2013 12:15 – Operational releases from North
Pine Dam to maintain lake levels near temporary Full Supply Level.

Phase 3: Flood Releases 27/1/2013 12:15 to 29/1/2013 6:00 – Flood operations under a declared Flood
Event.
Details of the dam operations, lake levels and release rates are included in a tabular in Appendix C.
Page 43
Table 6.1 – North Pine Dam Operating Summary
Dam Lake
Level
Modelled
Inflow*
Dam Gate
Releases
Event Details
(m AHD)
(m3/s)
(m3/s)
23/01 9:00
Event modelling start time
38.73
0
No gated releases
25/01 14:15
Temporary FSL advised for North
Pine Dam
38.76
10
No gated releases
25/01 20:00
Releases commence to draw lake
to temporary FSL. Youngs
Crossing closed. Releases
ramped up to a peak rate of
300 m3/s during overnight draw
down
38.77
10
First commenced at
20:00, increased up
to 300m3/s during
release period
26/01 7:00
Situation Report
38.38
10
95
26/01 8:15
Releases from North Pine Dam to
achieve temporary FSL complete,
Youngs Crossing re-opened
38.37
10
Overnight releases
concluded
26/01 19:00
Situation Report
38.42
40
None
26/01 20:00
Operational releases commence
to maintain dam near temporary
FSL, Youngs Crossing closed
38.43
40
Initial release rate of
75 adopted
27/01 2:45
Operational release rate
increased to maintain dam near
temporary FSL
38.44
150
Release rate
increased to 185
27/01 7:00
Situation Report
38.44
270
185
27/01 10:00
Operational release rate
increased to maintain dam near
temporary FSL
Current peak modelled inflow to
North Pine Dam of 430 m3/s (no
forecast rain)
38.48
430
Release rate
increased to 300
38.55
540
300
39.09
1,400
300
Date & Time
PHASE 1
PHASE 2
PHASE 3
27/01 12:15
27/01 16:00
Flood Event declared in North
Pine Dam catchment.
Lake level below 39.6 m AHD,
releases maintained at 300 m3/s
Peak inflow rate estimated to be
greater than 500 m3/s. Hence
North Pine Dam operating under
Large Flood Event strategy
Discussions with MBRC to advise
of possible dam operating
strategy. Advised that, with
forecast rainfall scenario, peak
outflows from North Pine Dam
Page 44
Date & Time
Event Details
Dam Lake
Level
Modelled
Inflow*
Dam Gate
Releases
(m AHD)
(m3/s)
(m3/s)
39.30
1,460#
420
may be up to 1,300 m3/s
27/01 17:00
Commenced increasing release
rate; increased from 300 m3/s to
600 m3/s. See discussion below
for basis
Modelled peak inflow rate to North
Pine Dam
27/01 19:00
Situation Report
39.66
1,300
610
27/01 21:00
Peak North Pine Dam lake level
39.80
1,000
730
27/01 22:00
Peak North Pine Dam release
rate
39.78
830
830
28/01 2:30
North Pine Dam release rate
reduced progressively to 600 m3/s
and maintained at this flow rate
39.74
640
620
28/01 7:00
Situation Report
39.69
490
620
28/01 19:00
Situation Report
39.20
150
600
28/01 22:15
Commenced progressive gate
closing sequence
39.00
120
600
29/01 6:00
Gates closed at North Pine Dam
to allow for re-opening of Youngs
Crossing. Fish recovery
conducted
38.80
75
0
* - these flows are based on the URBS hydrologic model run at the Flood Event conclusion. Some variability in these
estimates occurred at the given event time as model parameters varied during event calibration.
#
- a post event analysis was undertaken whereby an inflow time series was estimated by back calculation using observed
3
release rates and lake levels. This approach established a peak inflow rate of approximately 1,650 m /s; a value which is
considered to be a more accurate estimate of event peak inflow.
Phase 1: Reduction to Temporary Full Supply Level
Gated releases commenced from North Pine Dam at 20:00 on 25/1/2013 in response to the declared
temporary Full Supply Level gazetted by Government earlier that day. These releases were progressively
increased to a rate of approximately 300 m3/s by 26/1/2013 at 1:00. This release rate was maintained up to
6:00 on the same day, at which time gates were progressively closed. Gates were fully closed at 8:15 on
26/1/2013 with the North Pine Dam lake level 38.37 m AHD.
Phase 2: Operational Releases from North Pine Dam to maintain lake levels near temporary Full
Supply Level
Following gate closure the lake level at North Pine Dam rose slowly to a level of 38.43 m AHD by 20:00 on the
same day. In response to this, operational releases were commenced from the dam via gates to maintain the
lake level near the temporary Full Supply Level of 38.4 m AHD. To achieve this, releases were commenced
at a rate of 75 m3/s and maintained at this rate until 2:45 on 27/1/2013 at which time the dam lake level was
38.44 m AHD.
Page 45
In response to the rising lake level, operational releases were increased to 185 m3/s between 2:45 and 10:00
on 27/1/2013. Over this period, the dam lake level rose from 38.44 m AHD to 38.48 m AHD. At 9:45 a gate
operations directive was issued to North Pine Dam to open additional gates to achieve a release rate of
300 m3/s, which was reached at 11:00.
Phase 3: Flood Releases under a declared Flood Event
At 12:15 on 27/1/2013 a Flood Event was declared for the North Pine Dam system. This declaration was
made as the lake level was predicted to exceed 39.6 m AHD (at the time of declaration the North Pine Dam
lake level was 38.55 m AHD and rising). A model run with no forecast rainfall performed at the same time
identified a peak inflow to North Pine Dam in excess of 500 m3/s, resulting in the Flood Event being declared a
large flood event as per the Manual definition.
Releases from North Pine Dam were maintained at 300 m3/s from Flood Event declaration until 17:00 on
27/1/2013. During this time, discussions were held with BoM as to the likely forecast rainfall for the remainder
of the Flood Event. Arising from these discussions, a forecast rain scenario was modelled where the North
Pine Dam catchment received an additional 100 mm of rainfall in the following 12 hours. This scenario was
predicted to result in a peak inflow to North Pine Dam of 1,500m3/s, a peak lake water level of 40.1 m AHD
and a peak outflow rate of 1,500 m3/s (as per Appendix C of the Manual). The concurrent model scenario with
no consideration for forecast rainfall predicted a peak inflow to North Pine Dam of 1,300 m3/s, a peak lake
water level of 39.74 m AHD and a peak outflow rate of 620 m3/s. Given the vulnerability of downstream
infrastructure to flows in excess of 900 m3/s, an operating plan was developed that increased release rates
from 17:00 on 27/1/2013 in advancement of the gate settings established in Appendix C of the Manual. This
approach was developed so as to prevent where possible peak dam releases greater than 900 m3/s at the
time of the peak of dam lake level.
Directing dam operations to this plan, releases from North Pine Dam were progressively increased from
300 m3/s at 17:00 up to 830 m3/s at 22:00. During this period, dam lake levels peaked for the Flood Event at
39.80 m AHD.
In response to slowly dropping dam lake levels and reduced ongoing rainfall, release rates from North Pine
Dam were progressively reduced from 830 m3/s at 00:00 on 28/1/2013 to 620 m3/s at 2:30 on the same day.
The dam gate setting at this point, comprising a total of 26 gate opening increments, was maintained for the
following 19 hours as the dam lake level receded and release rates dropped to 600 m3/s. Gate closure
commenced at 22:15 on 28/1/2013, and gates were closed at 6:00 on 29/1/2013 when the dam lake level was
38.80 m AHD. The operational plan at this stage was to allow Youngs Crossing to be open to traffic during
daylight hours of 29/1/2013, with a then planned final gated release from North Pine Dam to return the lake to
the temporary full supply level during the following night.
At 14:30 on 29/1/2013, the Flood Operations Centre was notified that the temporary Full Supply Level for
North Pine Dam was revoked effective immediately. At this time, the dam lake level was 38.85 m AHD and
0.75 m below the permanent full supply level. Further releases were not necessary and consequently, the
Flood Event for North Pine Dam was declared complete.
6.2
Compliance with Operating Manual
This Flood Event was managed under Revision 7 (October 2012) of the Manual of Operational Procedures at
North Pine Dam. The operating strategies applied during the management of the Flood Event were compliant
with the Manual. The applicable operating strategies were established, reviewed and documented as the
Flood Event occurred. The Senior Flood Operations Engineers had agreement of who was in charge of
operations following declaration of the Flood Event, and flood operations were undertaken in accordance with
the directions of the Senior Flood Operations Engineers.
Assessment of the operational compliance for North Pine Dam for this Flood Event is complicated by the
declaration of a temporary full supply level. At the time of the event declaration, the Manual did not include
any provisions for the reduction in the full supply level.
Page 46
To allow for the releases required to draw the dam lake level to the declared temporary full supply level, a
Revised Interim Program to the Moreton Resource Operation Plan (ROP) was made on 25/1/2013. The
conditions of this are contained in Section 2 of this report.
These conditions direct that, prior to the declaration of a Flood Event, releases at North Pine Dam were
operational releases under the ROP. This covers the two report periods of Phase 1 and Phase 2 (from
23/1/2013 at 9:00 to 27/1/2013 at 12:15).
A Flood Event was declared at 12:15 on 27/1/2013. For the North Pine Dam system, a Flood Event is to be
declared when it is judged likely that:

the predicted lake level in the dam will exceed FSL (39.6 m AHD), and

a release of water from the radial gates will be required.
Such a declaration can be made prior to the lake level exceeding FSL.
While a temporary full supply level of 38.4 m AHD was declared and ROP amendments made to facilitate
operation at lake levels between this elevation and the permanent full supply level of 39.6 m AHD, the Manual
defines the FSL for North Pine Dam as 39.6 m AHD with no provision for a temporary FSL measure. For
compliance with the Manual, a Flood Event was declared for the North Pine Dam system at 12:15 27/1/2013
on the basis that the predicted lake level would exceed 39.6 m AHD, recognising that a temporary full supply
level enabled releases for lesser predicted lake levels earlier in the Flood Event.
At the time of the Flood Event declaration, the estimated peak inflow to North Pine Dam was greater than 500
m3/s and the operating strategy of a Large Flood Event was applied as per the Manual.
The flood mitigation objectives of North Pine Dam operations are listed in the Manual in descending order of
importance as follows:

Ensure the structural safety of the dam

Minimise disruption to the community in areas downstream of the dam

Retain the dam near FSL at the conclusion of the Flood Event

Minimise impacts to riparian flora and fauna during the drain-down phase of the Flood Event.
From the time of event declaration to 17:00 on the same day, release rates from North Pine Dam were
3
maintained at 300 m /s, consistent with that applied under the ROP operating conditions.
As discussed in Section 6.1 of this report, a model scenario performed at 16:00 on the same day with no
forecast rainfall predicted a peak inflow to the dam of 1,300 m3/s and the forecast rainfall scenario predicted a
peak inflow of 1,500 m3/s. A gate release strategy for North Pine Dam was implemented from 17:00 on
27/1/2013 that directed more gate openings for a given lake level than is prescribed in Appendix C of the
Manual. This approach was adopted as it resulted in a lower peak lake level (ensuring the structural safety of
the dam) and a corresponding lower peak release rate (minimising disruption to the community in areas
downstream of the dam, and specifically maintaining release rates below the estimated capacity of AJ Wylie
Bridge). The peak release rate from North Pine Dam from this strategy was 840 m3/s with a peak inflow to the
dam from the event of approximately 1,650 m3/s (based on post event analysis).
For the remaining objectives for North Pine Dam operations, the dam lake level at the conclusion of the Flood
Event was 38.80 m AHD (0.4m above the temporary FSL and 0.8m below FSL). This outcome was a
consequence of the revocation of the temporary full supply level declaration prior to the event completion.
The finally adopted gate closure strategy allowed for fish recovery.
Page 47
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Page 48
7.
COMMUNICATIONS
7.1
Overview
7.1.1
Summary Types of Communication
Key forms of communication internally and with stakeholders during the Flood Event included:

Situation Reports

external agencies providing key information to inform dam operations, and for information flow to the
public

gated dam summary status reports

communication with dam operators.
Key aspects of the communications are described herein.
7.1.2
Statement of Basis of Reporting
For the purpose of this Flood Event report, the description of communications was prepared from original
documents of sent or received communications, and reference to the Flood Operations Centre email database
and Flood Event Log for time references or miscellaneous communications.
7.1.3
Communications Protocol
Important formal communications regarding the dam flood operations were undertaken in accordance with the
2012-13 Dam Release Communications Protocol for the Brisbane River and North Pine River Catchments,
Final Draft V2.
The communication protocol was initiated by the Queensland Government and has the purpose of ensuring
communication arrangements between local and State Government and stakeholders are effective, coherent,
and timely. The protocol is directed towards respective stakeholder responsibilities to distribute information to:

ensure public safety

keep stakeholders engaged and informed

support Queensland Government disaster management activities.
The respective agency and stakeholder responsibilities are described in the communication protocol and are
not discussed further in this report.
For the Seqwater role in dam flood operations, the protocol is specifically relevant to issuing of Situation
Reports, and notification of actual and projected dam outflows to relevant agencies.
7.2
Situation Reports
7.2.1
Content and Preparation
The Situation Reports were prepared with the intent to communicate key information regarding the current
status of the dams, strategies and associated dam operations. The Situation Reports also described a
forward outlook based on information and trends known at the time of each report. A generic report structure
and indicative content guidance for the Situation Reports had been agreed prior to the wet season and
included with the Communications protocol.
Each Situation Report summarised the operations of all four gated dams operated by Seqwater. The relevant
aspects of the North Pine Dam operations described in the Situation Reports included:

forecast rainfall

overall strategy
Page 49

key measures of the current situation which varied depending on the significance for the particular phase
of the Flood Event:
o
dam level (current and peak) and where relevant volumes
o
inflows and trends
o
gate status, releases (current and peak)
o
operating strategy (as defined by the Manual)
o
status and/or predictions for bridges

discussions held with councils and State agencies

possible developments and relevant discussion.
The Situation Reports included appropriately worded limitations regarding reliance on such reports, with a
cautionary note that circumstances can change quickly and reference should always be made to the most
recent report.
The Situation Reports were prepared by the Senior Flood Operations Engineer for each shift using live
operational data relevant at the time of issue. It is important to note that in real-time operations forecast
predictions evolve as the event unfolds, as more data is collected and, as improved forecasting system model
calibration is achieved, with the benefit of more complete data. The accuracy of reported forecast predictions
improved through the event. No attempts were made to retrospectively document reasoning in each current
Situation Report for significant shifts in predictions relative to earlier Situation Reports.
7.2.2
Distribution of Situation Reports
Situation reports were distributed to the agencies or groups listed in Table 7.1.
Table 7.1 – Distribution of Situation Reports
State Government
Local Government
Other Agencies / Stakeholders
Queensland Department of Energy
and Water Supply
Brisbane City Council
Commonwealth Government
Bureau of Meteorology
(Flood Warning Centre, and
Regional Forecasting Centre)
Department of Transport and Main
Roads (including Maritime Safety)
Ipswich City Council
Queensland Urban Utilities
Department of Premier and Cabinet
(Ministerial Representatives)
Somerset Regional Council
CS Energy
Department of Community Services
Moreton Bay Regional Council
Emergency Management
Queensland including State Disaster
Coordination Centre
Redland City Council
Internally within Seqwater
including all FOC and Dam
Operations personnel, executive
management, media and
communications personnel
Queensland Police Service
7.2.3
Situation Reports Issued
Over the duration of the Flood Event, 25 situation reports were issued. Situation Reports with information
relating to North Pine Dam operations were limited to the first 12 Reports up until the flood releases for North
Pine dam ceased in the early morning on 29/1/2013, and the temporary full supply level declaration for North
Pine dam was revoked later that day.
Copies of the issued Situation Reports are presented in Appendix D.
Page 50
A list of the Situation Reports and succinct summary of contents relevant to North Pine Dam operations is
presented Table 7.2. The summarised tabulation is not intended to describe the detailed actual or forecast
data for levels and flows for the dam; rather, the purpose of the Situation Report tabulation is to summarise
the information that was communicated to stakeholders. For detailed information on dam levels and flows
refer to description of dam operations in Section 6.
It is noted that Situation Reports 8 and shortly thereafter list the event declaration time of 16:00 27/1/2013.
The event log and event notes list the event declaration earlier at 12:15 on 27/1/2013, and this earlier time is
the correct time of declaration.
Table 7.2 – Situation Reports
No.
Date Time
Summary
1
Fri 25/01/2013 15:30
Seqwater Flood Operations Centre mobilised.
Summarised rainfall forecast. No gate releases at this time.
Initial notification prior to commencement of release for drawdown in
response to Ministerial direction of temporary reduction in FSL.
Advice on potential impacts on bridges and notifications to councils.
2
Fri 25/01/2013 20:00
Updated rainfall forecast as received from BOM.
Notified FSL drawdown releases using gates occurring at North Pine Dam.
Advised potential bridge closures.
3
Sat 26/01/2013 07:30
Advised FSL drawdown releases from North Pine Dam completed – dam at
88% of normal FSL capacity (lake level 38.38 m AHD).
Advised releases expected to recommence later in the day as rain occurs.
Youngs Crossing likely to be opened during the day and if releases
recommence crossing will again be closed.
4
Sat 26/01/2013 22:00
Updated rainfall forecast as received from BOM.
Releases at North Pine Dam recommenced to maintain lake level at about
the declared FSL. Current release approximately 80 m3/s.
Youngs Crossing currently closed. May open tomorrow depending on dam
levels and actual and anticipated rainfall.
5
Sun 27/01/2013 06:00
Updated rainfall forecast and flood warning as received from BOM.
3
Current release approximately 180 m /s, and releases expected to continue
into the afternoon when heavy rainfall is expected. Overall strategy to
maintain lake level near the declared FSL in preparation for expected heavy
rainfall.
Youngs Crossing currently closed and not expected to reopen today.
6
Sun 27/01/2013 12:00
Updated rainfall forecast as received from BoM.
Current release approximately 300 m3/s, and releases expected to continue
to tomorrow. Lake level currently 38.5 m AHD. Overall strategy to minimise
downstream disruption.
Youngs Crossing currently closed and not expected to reopen today.
7
Sun 27/01/2013 16:00
Updated rainfall forecast as received from BoM indicated easing off of
predicted rainfall.
Current lake level 38.9 m AHD and releasing 300 m3/s. Lake level is rising
rapidly and release rates expected to increase substantially over six to 12
hours. Strategy is to minimise downstream disruption.
Youngs Crossing closed and not expected to reopen today.
8
Sun 27/01/2013 21:30
No change in forecast rainfall. Update mainly focussed on dam strategy and
operations.
Page 51
No.
Date Time
Summary
Flood Event for North Pine dam declared at 16:00 today#. Flood is classified
as large in accordance with Manual with dam inflows approaching
1,300 m3/s. Lake level is 38.9 m AHD and releases are 840 m3/s. Releases
expected to increase over next six hours. Strategy is to minimise
downstream disruption.
Youngs Crossing closed and not expected to re-open today.
9
Mon 28/01/2013 06:00
No change in forecast rainfall. Update mainly focused on dam strategy and
operations.
Lake level is 39.72 mAHD and falling slowly after peaking at 23:00 previous
evening. Current releases at 620 m3/s and releases to drain dam back to full
supply level will continue for rest of day, provided no further significant
rainfall occurs. Strategy is to minimise downstream disruption.
Youngs Crossing closed and not expected to re-open today. Noted also that
Sideling Creek Dam is spilling.
10
&
10A
Mon 28/01/2013 19:00
& correction issued
Mon 28/01/2013 21:30
Updated rainfall forecast – easing off.
Lake level is 39.35 mAHD and falling slowing. Current releases at 600 m3/s
and releases to drain dam back to full supply level will continue overnight.
Strategy is to drain dam to FSL while minimising downstream disruption.
Youngs Crossing closed. Advised some possibility to shut down release
next morning to allow traffic over Youngs Crossing subject to reassessment
tomorrow morning. Potential Youngs Crossing re-opening also subject to
spillway flows from Sideling Creek Dam.
Advised release may then need to recommence tomorrow night to complete
drain-down to FSL.
Note no change in corrected Situation Report (10A) issued at 21:30 as this
correction related to Wivenhoe Dam-Somerset Dam status.
11
Tue 29/01/2013 07:00
No change in 24 hour forecast rainfall. One-week outlook indicated no
significant rainfall.
Lake level is 38.8 mAHD and steady. Releases temporarily ceased (at
05:30) to allow re-opening of Youngs Crossing during the day.
Releases may recommence tonight to drain the lake level to the declared
temporary FSL, and likely to again close Youngs Crossing.
Strategy is to drain dam to FSL while minimising downstream disruption.
Sideling Creek dam spillway flow continuing to recede.
12
Tue 29/01/2013 18:00
Updated forecast rainfall – no significant rain expected.
The temporary full supply level for North Pine Dam was revoked today.
No further releases required from North Pine Dam. Lake level is 38.8 m
AHD.
13
to
25
#
Wed 30/01/2013 06:00
to
Tue 05/02/2013 10:15
Subsequent Situation Reports issued by Seqwater did not provide further
information reports for North Pine dam following the completion of Flood
Releases on 29/1/2013.
- noted to be incorrect time, refer to discussion in text preceding table
7.3
External Agencies
7.3.1
General Communications
Communications were undertaken between Seqwater and relevant external agencies to:

inform assessments, strategy selection and decision making for the dam operations
Page 52

provide advice to stakeholders to support their activities in response to flooding and actual or potential
road closures.
The majority of communications were directly with the rostered Seqwater Flood Operations Centre personnel.
Some communications were directly between external agencies and the Seqwater Dam Operations Manager
or General Manager Water Delivery, and these communications were relayed to the Flood Operations Centre.
All communications relevant to the dam flood operations were recorded in the Event Log. A combined Event
Log was used to record the operations of the Wivenhoe-Somerset Dam operations and the North Pine Dam
operations. Telephone calls to and from the Flood Operations Centre were recorded.
The types of matters and situations when communication was undertaken with external agencies included:

participating in teleconferences that were led by Emergency Management Queensland

contact with BoM for briefing of forecasts and obtaining updates on trends

initial and then ongoing discussions with Moreton Bay Regional Council regarding potential inundation of
bridges, actual bridge closures, and re-opening of bridges

discussions with Transport and Main Roads representatives (including consultants on behalf of contract
repair works underway at A J Wylie Bridge) regarding potential inundation of A J Wylie bridge and other
flood matters at this bridge related to construction works underway

discussions with Moreton Bay Regional Council advising of strategy generally and potential releases
from North Pine Dam

discussion with Department of Energy and Water Supply regarding declaring a Flood Event

discussions with Energex to arrange and follow-up with power restoration at North Pine Dam.
Details of specific communications were recorded in the Flood Event Log.
7.3.2
Ministerial Briefing Advice
Ministerial briefing was prepared for the Queensland Government in the lead up to the Flood Event. The
briefing information relevant to North Pine Dam is presented in Table 7.3.
Table 7.3 – Ministerial Briefing Advice
No.
Date
Summary
1
Thu 24/01/2013
Assessment based on data and forecast available 24/01/2013 19:00.
Catchment status (potential rainfall loss), forecast rainfall, dam status
(current levels), potential dam inflows, potential dam releases for a range of
potential rainfall scenarios.
Advice that as rain systems moves closer and BoM forecasts become more
certain, the potential for early releases should be reassessed the next day.
7.3.3
Information to the Public
Seqwater provided several communication pathways to inform the public of dam operations. These included
access to a 1800 telephone recorded message, website updates, email/SMS notification via the Early
Warning Network and media releases. Information was prepared and regularly updated by the Seqwater
communications personnel from Situation Reports. The duty engineer reviewed the final drafts of the public
communication information before it was issued.
7.4
Gated Dam Reports
Summary reports for four Seqwater dams with spillways that release floodwater via gates (gated dam reports)
were prepared by the Seqwater Flood Operations Centre for internal distribution. The reports were distributed
Page 53
to key Seqwater managers and personnel for their activities in communications with State Government,
councils and the Department of Energy and Water Supply to ensure consistency of information.
The contents of the reports included dam level, dam volume (as % of full supply volume), catchment rainfall
since event start, current inflows and release flow, and volume of inflow and outflow since event start for each
gated dam.
7.5
Dam Operators
Regular communications were maintained between the Seqwater FOC and dam operators from mobilisation
of the FOC on 25/1/2013 until the Flood Event was declared complete on 29/1/2013.
There was no loss of communications between the FOC and dam operators during the Flood Event. There
was a temporary loss of fax communication at the dam office around 16:00 27/1/2013 and an alternate fax at
the dam was used. This did not hinder operations, as alternative means (phone, email) were used to transmit
the Gate Directive.
The relevant matters and situations regarding the subject of communications between the Flood Operation
Centre and Dam Operators included:

confirming preparedness (checklists) upon mobilisation and identifying any concerns

instructing and confirming Gate Directives

instructing or receiving observations taken, when, what, why and changes in frequency to suit
circumstances at the time (for example dam level gauge board readings)

instructing dam safety checks and receiving observations

receiving information from personnel supporting the dam operators regarding status of bridges and roads
downstream of Wivenhoe Dam

information regarding gate operations strategy, outlook and trends, including updates on likely duration
of gate operations at each dam to ensure roster requirements could be fulfilled

relay of relevant communications or any concerns between the dam operators and external stakeholders

planning of fish recovery activities upon completion of flood releases.
Page 54
8.
FLOOD EVENT MAGNITUDE
8.1
Introduction
This section of the report provides an assessment of the magnitude of the Flood Event by comparing it with
previous flood records and design rainfall information.
The significance of this Flood Event can be determined by comparing rainfall, water levels and flood volumes
measured during the period with historical records, and then undertaking a statistical analysis of this
information. Australian Rainfall and Runoff (AR&R) categorises events according to their Annual Exceedance
Probability (AEP), as illustrated in Figure 8-1. BoM adopts a flood classification system based on minor,
moderate and major flood levels which are defined by the BoM in conjunction with local councils.
Figure 8-1 – Annual Exceedance Probability of Flood (Source: AR&R)
Rainfall totals and intensities can be compared with those recorded during other significant events to
determine the significance of the Flood Event. Rainfall stations in South East Queensland have good record
lengths that, in some cases, are greater than 100 years and, therefore, provide an effective basis for analysis.
The analysis of rainfall intensity rather than depth provides a good indicator of the magnitude of floods in
terms of peak flows and volumes.
Water level stations generally have shorter record lengths than rainfall stations, leading to a greater level of
uncertainty when comparing recorded and historic water level data to determine event significance. Automatic
stations have only been in widespread use since the 1960s, so continuous water level records are generally
only available for maximum periods of approximately 50 years.
8.2
Rainfall Intensity
Intensity Frequency Duration (IFD) analysis refers to the statistical probability of rainfall intensities for specific
durations. Rainfall is typically described as depth in millimetres (mm) falling over a specified duration or period
in hours. The rainfall rate or intensity is usually defined as the depth of rainfall per hour.
To determine the severity of a particular rainfall event, the intensity over particular periods of interest is
compared with historical records to determine its frequency of occurrence. The Annual Exceedance
Probability (AEP) is used to define this frequency of occurrence and is defined by the BoM as “the probability
that a given rainfall total accumulated over a given duration will be exceeded in any one year”.
Depth and intensity may be used in IFD analysis; however, the BoM prefers to simply use rainfall intensity
(mm/h).
Page 55
There are two generally accepted methods generating IFD data:

Australian Rainfall and Runoff (AR&R) (IEAust 1987);

CRC-FORGE (Hargraves, 2004 & 2005).
In the North Pine River, the CRC-FORGE method and AR&R produce similar estimates for 1% AEP for
durations from 24 hours to 72 hours. The CRC-FORGE method is the only IFD method used in relation to
catchments that provides design rainfall estimates for durations up to 120 hours.
The CRC-FORGE method is based upon a regional rainfall frequency analysis that derives rainfall depth
estimates of large to rare flood events and uses the concept of an expanding region focused at the site of
interest. When using CRC-FORGE, design rainfall estimates for frequent events (1 in 50 and 1 in 100 AEP)
are based on pooled data from a few stations around the focal point, while design rainfall estimates at the
AEP limit of extrapolation (1 in 2,000) are based on pooled rainfall data from up to several hundred stations.
Before data from different sites can be pooled, maximum annual rainfalls from each site need to be
standardised by dividing by an index variable. The index variable may be the mean annual maximum for the
site, or rainfall of any specified AEP that is reasonable and accurately determined from a short record. An
Area Reduction Factor (ARF) is also introduced to correct the variation of rainfall intensity over a large
catchment area and to convert point rainfall estimates to areal estimates.
The CRC-FORGE method was developed using daily rainfall totals. It should be noted there is some
uncertainty in the AEP estimates of the recorded rainfall produced by the CRC-FORGE method for durations
less than 24 hours. The shorter durations are extrapolated using ratios calculated from AR&R.
It is important to note that rainfall of a particular AEP does not necessarily translate into a flood of the same
AEP. Other factors such as catchment and dam conditions must be taken into account when determining the
AEP of the resulting flood.
8.2.1
Point Rainfall Intensity
For the Flood Event, the AR&R method was used to derive point rainfall estimates for storm durations from 15
minutes to 72 hours.
Table 8.1 summarises the highest AEPs for selected stations in the North Pine Dam catchment. The table
shows that for durations of more than 24 hours, the highest AEPs of the recorded rainfall were up to 1 in 50
for longer durations.
Table 8.1 – Point IFD Analysis for Selected Stations
Duration
Station
Number
Name
(Hours)
1
3
6
12
24
48
72
540185
Mt Mee AL-P
<1
1
2-5
5-10
10-20
20-50
50
540189
Baxters Ck
<1
2-5
10
20
20-50
20-50
20-50
540409
Lacys Ck
<1
1
2-5
5
10
10-20
20
540545
Raynbird Ck AL
<1
2
10
20
50
50
50
Page 56
Figure 8-2 – Point IFD Analysis for Selected Stations
8.2.2
Catchment Rainfall Intensity
While Point IFD analysis demonstrates the rainfall intensity in the immediate vicinity of the station, it does not
indicate the significance of the rainfall over the entire catchment. The catchment average rainfall is
determined by applying a weighting to each station in the network, then adding up the weighted station rainfall
for each period of the analysis. Catchment IFD analysis derived using CRC-FORGE is based upon assumed
idealised spatial and temporal patterns, which can be quite different to the actual Event rainfall distributions.
By their nature, catchment average rainfall intensities tend to be lower than Point intensities, due to the spatial
variation of rainfall through the catchment, with some areas recording higher rainfall than others.
The figure below shows the catchment IFD analysis for the main catchments based on CRC-FORGE design
rainfalls. The AEPs for the North Pine River to North Pine Dam catchment were between the 1 in 20 and 1 in
50 for rainfall durations between 12 hours and 120 hours.
Page 57
Figure 8-3 – North Pine River to North Pine Dam IFD Analysis
8.3
Comparison with Historical Rainfalls
Table 8.2 shows a comparison between gross catchment rainfalls recorded in this Flood Event compared with
the floods of 1974 and 2011. Catchment rainfalls were less than the rainfalls recorded in the two previous
floods.
Table 8.2 – Historical Total Rainfall
Event
Parameter
1974
2011
2013
Event Total (mm)
760
569
529
Maximum Intensity (mm/hr)
58
49
25
While the 2013 event had a similar depth of rain to 2011, the maximum rainfall intensity of 2013 was only half
that of 2011.
Page 58
8.4
Comparison with Historical Flood Volumes
Table 8.3 – Comparison of Historical Flood Event Volumes
Peak Flows
Event
Flood Volumes
Inflow
Outflow
Inflow
Outflow
m3/s
m3/s
ML
ML
Jun-1983
760*
36,900
Apr-1988
790
630
178,000
75,900
Mar-1989
1,430
1,440
124,000
124,000
Apr-1989
1,150
980
94,700
96,000
Dec-1991
1,740*
70,100
0
91,000
0
May-1996
Feb-1999
1,180
0
117,000
0
Feb-2001
420
0
43,800
0
Mar-2004
460*
0
27,500
0
Nov-2008
220*
0
14,100
0
Apr-2009
790
0
45,600
0
May-2009
910
330
79,400
22,600
Feb-2010
380
360
57,700
57,500
Oct-2010
1,000
910
69,400
61,300
Jan-2011
3,480
2,850
202,000
206,000
Jan-2012
850
630
71,300
65,300
Jan-2013
1,650
840
101,000
97,000
* - these values are estimates
The January 2013 event was the third highest peak inflow, while the flood volume was fifth highest since the
dam was completed in 1975.
8.5
Conclusion
This Flood Event can be classified towards the lower end of a Large flood as classified by AR&R.
Page 59
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Page 60
9.
FLOOD ATTENUTATION
9.1
Flood Attenuation
North Pine Dam does not include any dedicated flood storage compartment with sufficient freeboard to
perform a flood mitigation function. Under normal flood operations, the Manual dictates that flood waters are
released at close to the same rate as the incoming flood. However, due to the normal operation of the dam
flood mitigation benefits may occur.
The circumstance under which North Pine Dam was operated during the Flood Event has been described in
Section 6. Of these circumstances, three factors were of particular influence on the ultimate release rates
from North Pine Dam during the Flood Event:

The temporary FSL provided an additional storage allowance within the dam prior to the lake level
reaching 39.6 m AHD where Manual directed operating rules to apply.

The ROP interim program allowed for releases from North Pine Dam up to 300 m3/s for lake levels below
39.6 m AHD outside of a declared Flood Event, providing the opportunity for further flood attenuation.

Following the declaration of a Flood Event, gate openings were adopted that were in advance of the
Gate Operating Tables of Appendix C of the Manual.
To quantify the flood attenuation of North Pine Dam during this Flood Event, a model scenario was developed
post-event whereby no temporary fully supply level was declared and the Gate Operating Tables of Appendix
C were adopted relative to dam lake level. This scenario reflects the operating conditions that would apply in
a loss of communications scenario.
Figure 9-1 shows a comparison between the actual releases and the releases that would have been made if
gate operations had followed prescriptive tables in the Manual without the interactive professional judgement
of the flood engineers.
This scenario of prescriptive operations relative to dam level would have resulted in a peak outflow from North
Pine Dam of approximately 1,550 m3/s. The actual peak release rate was approximately 830 m3/s.
It is difficult to establish the proportion of contribution of the three above listed influential factors on this
attenuation achieved by North Pine Dam for the Flood Event. This outcome was achievable specific to this
Flood Event due to factors such as a low intensity of rainfall after 00:00 on 28/1/2013. More rigorous
consideration of a range of conditions should be performed prior to any expectation that such an outcome can
be achieved in other events.
Page 61
Figure 9-1 – Comparison of North Pine Dam outflows; Event Recorded and Loss of Communications Case
Page 62
10. EVENT REVIEW
10.1
Forewarning of the Event
Section 2 of this report includes discussion of the seasonal outlooks produced by BoM. This discussion
highlights the uncertainty in these outlooks; noting both the changeability of the outlook from month to month
preceding the Flood Event and the potential for floods to occur during periods identified as climatically being
neutral.
Forewarning of the rainfall associated with ex-tropical cyclone Oswald developed early in the week prior to the
Flood Event. Such forewarning is generally available with higher certainty for rainfall events associated with
ex-tropical cyclones such as this event, and this warning time allowed for appropriate control measures to be
applied. Bureau of Meteorology short term (day-to-day) forecasts of the timing of the rainfall onset were
valuable in allowing dam preparations such as management of the temporary full supply level implementation.
The relationship used in API model significantly underestimated the Initial Loss. While this did not have a
significant impact on flood operations as Initial Loss is adjusted during the Flood Event to match recorded
water level rises, it is recommended that the API-IL relationship for Seqwater catchments be re-derived, taking
into account data from the latest Flood Event.
10.2
Monitoring Network
Overall, the performance of the Seqwater monitoring network is considered satisfactory.
Failure rate of Seqwater’s rainfall sensors was less than 1% and is below the level typically anticipated during
flood events. As rainfall is the primary input to the forecasting models, this had little impact on modelling.
However, the water level sensors at Dayboro Wastewater Treatment Plant and Kobble Creek both failed
during the recession of the flood and this requires further investigation to identify measures to improve
resilience of the gauges.
10.3
Forecast Rainfall during the Event
Verification of the 24 hour forecast rainfall provided by the PME model and the QPF as indicated in
Figure 10-1 shows that:

The PME consistently underestimated the average catchment rainfall.

The QPFs were initially high, probably based upon an expected early onset of the heavy rain. Initially on
27/1/2013, the QPF underestimated the catchment average rainfall for the next 24 hours but were within
the forecast range later that day and early the next. The QPF underestimated the rainfall that occurred
at the end of the Flood Event.
Note, Figure 10-1 advances the timing of the QPF forecast rainfall by 24 hours to coincide with the time of the
realised accumulated rainfall.
Page 63
Figure 10-1 – Forecast Rainfall Verification
10.4
Model Performance and Ratings
An evaluation of the flood forecasting systems models and associated ratings used during the Flood Event
has been conducted. These include the API model used to assess catchment conditions at the start of the
Flood Event, and the URBS model and ratings used to estimate flows in the catchment to North Pine Dam.
Post the Flood Event, the hydrograph at Baxters Creek and the inflow to North Pine Dam, estimated by
reverse routing methods, were compared with the modeled flows from the URBS as indicated in Figure 10-2
and Figure 10-3.
Page 64
Figure 10-2 – Model Verification
Figure 10-3 – Model Verification
It should be noted that the station at Baxters Creek, while important in identifying when initial loss is satisfied
and run-off commences, represents only 40% of the catchment to North Pine Dam and significant run-off into
the dam can occur downstream of this station.
The parameters adopted in verifying the model to the rated flow at Baxters Creek and the estimated inflow are
within the acceptable ranges of those derived during model calibration and close to those used during the
Page 65
Flood Event. The models produced peak flows within 15% of the estimated peak flows and to within 7% of the
estimated flood volumes.
10.5
Forecasting Systems
10.5.1
Enviromon, URBS and Gate Operations Module
The Enviromon system performed satisfactorily and was easy to use and correct data. Data editing and
correction in Enviromon did not cause any problems. Transfer of rainfall and water level data to FEWS
performed as required every 15 minutes throughout the Flood Event.
The use of the URBS Control Centre via the Citrix system (a remote access portal) was very slow at times.
The speed could be improved by installing the URBS Control Centre locally. This would improve the
application but would not improve the speed of data extraction from Enviromon.
The current version of the URBS model performed adequately and the rating at Baxters Creek appears to be
satisfactory. However, the ratings at Dayboro Wastewater Treatment Plant and Kobble Creek should be
reviewed.
10.6
Dam Operations
Operations at North Pine Dam significantly attenuated the peak flow rate in the downstream North Pine River
in this flood event, as discussed in Section 9 of this report. This outcome was achievable to the specific
circumstances of this Flood Event, including:

a lowered lake level due to a declared temporary Full Supply Level

releases from the dam for lake levels below Full Supply Level

adopted gate openings that were in advance of the Gate Operating Tables of Appendix C of the
Manual.
A more rigorous consideration of a range of flood conditions and variability of forecasts for event predictability
should be performed prior to any expectation that such an outcome can be achieved in other events.
No significant issues were experienced in the operation of North Pine Dam during the Flood Event. Mains
power supply was lost to parts of the site for short periods of time during the Flood Event and planned back up
contingencies were utilised with no interruption to flood management. Implementation of the contingencies
worked well as the dam operators are trained in contingency actions as art of the regular training exercises.
10.7
Review of the Manual
The Flood Event was managed under a declared temporary full supply level for North Pine Dam of 38.4 m
AHD. As discussed in Section 2 of this report, unlike for the Wivenhoe and Somerset Dam system, the
current version of the Manual does not provide for flood operations below the permanent FSL. In this context
spillway gate releases from North Pine Dam when this lake level was below the lake level trigger defined in
the manual for flood operations were facilitated through conditions within the Revised Interim Program.
This current regulatory operating arrangement is inconsistent with the flood operation conditions of the
Wivenhoe and Somerset Dam Manuals. It is possible that operational decision for flood management
spanning across Resource Operation Plan and the Manual may not optimally address the objectives of North
Pine Dam flood strategies. Current aspects of the North Pine Dam Manual that are ideally suitable for
temporary full supply level declarations are:

a glossary defined “permanent full supply level” for the dam with no provision for a temporary lowering

recommended dam gate settings that are dependent on a lake level, with no provision for a temporary
lowering of the FSL.
Manual updates should be considered at the end of the current wet season to better address temporary full
supply level declarations for North Pine Dam.
Page 66
A further opportunity for improvement to the Manual was identified from the Flood Event. The Manual
currently includes a provision under the Large Flood considerations that:
To protect the safety of the Dam, the radial gates settings should fall no more than three gate
operations behind the settings shown in Appendix C. It is permissible to fall more than three
gate operations behind the settings shown in Appendix C if the safety if the Dam is protected
There is no equivalent provision to allow for advancement of gate settings ahead of those shown in
Appendix C to achieve the objectives of the Manual, including dam safety and minimisation of disruptions to
downstream communities. Inclusion of such a provision will also better enable a transition from operations
under a temporary full supply level to operations as per the Manual.
10.8
Staffing
Staffing of both the FOC and dam sites was appropriate for the duration of the Flood Event and no issues
were encountered.
As new systems are implemented to assist in the management of flood events, ongoing training will be
required to maintain a high level of technical competence with these developing systems.
10.9
Communications
Protocols that govern the inter-agency communications are produced by EWS. Given the recent large
reviews to many departmental structures, rationalisation of these protocols is required to reflect these recent
changes.
Effective two-way communications between the FOC and Moreton Bay Regional Council were maintained
throughout the Flood Event. Duty engineers acknowledge the role of the Director of Engineering,
Construction and Maintenance at Council in these effective communications and resulting good flood
management outcomes.
10.10 Dam Damage Assessment
Dam operators undertook twice-daily inspections of the dams during the Flood Event. No signs of flood
induced damage were reported during or immediately after the Flood Event.
Page 67
Blank page
Page 68
11. RECOMMENDATIONS
In addition to the ongoing improvement processes that apply to the management of flood events in the North
Pine Dam catchment, the following recommendations are identified from the review of the Flood Event are
made:

Seqwater will revise the methods by which the preceding catchment condition is estimated by the API
(antecedent precipitation index) method. It is recommended that these revised methods be applied once
finalised to allow for more accurate prediction of initial loss conditions prior to a rainfall event.

Ratings at Dayboro and Kobble Creek will be reviewed using reliable data from this Flood Event.

It is recommended that the Flood-Col and Flood-Ops systems be decommissioned following the end of
this current wet season as they are no longer in use, are based on unsupported software platforms and
have been superseded by more advanced technology;.

It is recommended that consideration be given to update the Manual at the end of the current wet season
to incorporate provisions for flood operations with a declared temporary full supply level, consistent with
the arrangements in place for the Wivenhoe Somerset Dam Manual. The benefit and risk of updating the
Manual immediately after the wet season will need to be carefully considered in context of the North Pine
Dam Optimisation Study that is currently underway.
Page 69
Blank page
Page 70
12. REFERENCES
Institution of Engineers, Australia (1987 and 2000) Australian Rainfall and Runoff Volumes 1 and 2
Queensland Government (2013) Water Supply (Safety and Reliability) Act 2008, Reprinted as in Force on
1 January 2013, Reprint 2F.
Seqwater (2012) Manual of Operational Procedures for Flood Mitigation at North Pine Dam, Revision
7 October 2012.
Seqwater (2012b) Flood Operations Statement of Preparedness: Wivenhoe, Somerset and North Pine Dams.
Page 71
Blank page
Page 72
APPENDIX A. REPORTING PROCESS SUMMARY
This report was prepared to the Flood Event Report Writing Methodology. This process was developed to
address recommendation 16.2 in the Queensland Flood Commission of Inquiry Final Report, March 2012.
The Report Writing Methodology identifies:

the legislative and Manual requirements for Report Content

confirms that the target audience includes technical and non-technical stakeholders and reviewers

the important principles of the Flood Event Report

the report structure and content.
Finally, the Report Writing Methodology prescribes an appropriate workflow methodology for the preparation
of the Flood Event Report. This workflow identifies the relative timing of information collation, analysis, review
and the formulation of recommendations arising.
Page 73
Blank page
Page 74
APPENDIX B. MODEL SCENARIO SUMMARY
Table B.1 – Pre Event Forecast Scenarios
Case
Archive File Name
Time of Scenario Capture
201301242027FR_U_NPD-Ops v10.5.xlsm
1
Forecast: 200mm with initial loss of 60mm
24/01 20:27
2
24/01 20:29
3
24/01 20:31
4
24/01 20:33
5
Forecast: 400mm with an initial loss of 60mm
24/01 20:37
6
Forecast: 400mm with an initial loss of 100mm
24/01 20:39
7
Forecast: 300mm with an initial loss of 60mm over
two days
24/01 20:43
8
Forecast: 300mm with an initial loss of 100mm over
two days
24/01 20:49
9
Forecast of 200mm over 60 hours starting 2pm
260113 - planned releases to get to 88% as per Gov
Changes - start at 7pm 250113
25/01 13:55
10
Initial Loss of 60mm and the PME forecast rainfall
applied to the model for the next 48 hours
25/01 18:07
11
Initial Loss of 60mm and the PME forecast rainfall
applied to the model for the next 48 hours
Page 75
25/01 21:27
Table B.2 – Mid Event No Forecast Rain Scenarios
Case
Archive File Name
1
201301260027NR_U_NPD-Ops v10.5_NR.xlsm
26/01 00:27
2
26/01 02:09
3
26/01 03:10
4
26/01 04:03
5
26/01 09:52
6
26/01 11:09
7
26/01 11:32
8
26/01 14:38
9
26/01 15:24
10
26/01 16:36
11
26/01 17:16
12
26/01 18:15
13
26/01 20:53
14
26/01 21:01
15
26/01 23:26
16
27/01 00:48
17
27/01 03:59
18
27/01 05:14
19
27/01 06:13
20
27/01 09:27
21
27/01 11:32
22
27/01 13:07
23
27/01 14:17
24
27/01 15:27
25
27/01 15:28
26
27/01 15:41
27
27/01 16:05
Page 76
Case
Archive File Name
28
27/01 16:12
29
27/01 17:06
30
27/01 18:42
31
27/01 19:52
32
27/01 20:33
33
27/01 22:06
34
27/01 22:33
35
27/01 23:43
36
28/01 00:31
37
28/01 01:20
38
28/01 02:49
39
28/01 03:24
40
28/01 04:10
41
28/01 06:35
42
28/01 18:51
43
28/01 21:30
44
28/01 22:01
45
28/01 22:15
46
28/01 23:30
47
29/01 00:18
48
29/01 01:11
49
29/01 02:28
50
29/01 03:10
51
29/01 03:37
52
29/01 05:11
53
29/01 06:15
54
29/01 06:59
55
29/01 09:18
Page 77
Case
56
Archive File Name
29/01 13:07
Table B.3 – Mid Event Forecast Rain Scenarios
Case
1
Archive File Name
NPD-Ops v10.5_FR1.xlsm
27/01 16:00
Table B.4 – Mid Event Actively Updated Scenarios
Case
Archive File Name
1
NPD-Ops v10.5_FR.xlsm
Ongoing
2
NPD-Ops v10.5_NR.xlsm
Ongoing
Page 78
APPENDIX C. DAM GATE OPERATIONS TABLES
Table C.1 – North Pine Dam Gate Operations
Date/time
ALERT
Gauge
Gauge
Boards
Gate settings
Storage
Volume
A B C D
m AHD
m AHD
ML
E
Gate discharges
Total
Outflow
Total
Inflow
A
B
C
D
E
3
3
3
3
3
m /s
3
m /s
m m m m m m /s m /s m /s m /s m /s
3
25/01/2013 09:00
38.76
196,689
0
0
0
0
0
0
0
0
0
0
0
5
25/01/2013 10:00
38.76
196,689
0
0
0
0
0
0
0
0
0
0
0
0
25/01/2013 11:00
38.75
196,488
0
0
0
0
0
0
0
0
0
0
0
0
25/01/2013 12:00
38.75
196,488
0
0
0
0
0
0
0
0
0
0
0
0
25/01/2013 13:00
38.75
196,488
0
0
0
0
0
0
0
0
0
0
0
33
25/01/2013 14:00
38.76
196,689
0
0
0
0
0
0
0
0
0
0
0
28
25/01/2013 15:00
38.76
196,689
0
0
0
0
0
0
0
0
0
0
0
28
25/01/2013 16:00
38.77
196,890
0
0
0
0
0
0
0
0
0
0
0
38
25/01/2013 17:00
38.77
196,890
0
0
0
0
0
0
0
0
0
0
0
0
25/01/2013 18:00
38.76
196,689
0
0
0
0
0
0
0
0
0
0
0
0
25/01/2013 19:00
38.77
38.76
196,890
0
0
0
0
0
0
0
0
0
0
0
75
25/01/2013 20:00
38.78
38.77
197,091
1
1
1
1
1
15
15
15
15
15
76
76
25/01/2013 21:00
38.77
38.77
196,890
2
1
2
1
2
38
15
38
15
38
143
83
25/01/2013 22:00
38.76
38.77
196,689
2
2
2
2
2
38
38
38
38
38
188
109
25/01/2013 23:00
38.74
38.75
196,287
2
2
2
2
2
38
38
38
38
38
188
48
26/01/2013 00:00
38.71
38.72
195,683
2
2
2
2
2
37
37
37
37
37
187
0
26/01/2013 01:00
38.67
38.68
194,879
3
3
3
3
3
61
61
61
61
61
307
51
26/01/2013 02:00
38.62
38.63
193,873
3
3
3
3
3
61
61
61
61
61
306
22
26/01/2013 03:00
38.57
38.59
192,867
3
3
3
3
3
61
61
61
61
61
305
25
26/01/2013 04:00
38.52
38.54
191,861
3
3
3
3
3
61
61
61
61
61
303
29
26/01/2013 05:00
38.47
38.48
190,856
3
3
3
3
3
60
60
60
60
60
302
0
26/01/2013 06:00
38.41
38.42
189,649
3
1
3
1
3
60
15
60
15
60
210
0
26/01/2013 07:00
38.38
38.38
189,045
1
1
2
1
1
15
15
37
15
15
96
0
26/01/2013 08:00
38.36
38.37
188,643
1
0
1
0
1
15
0
15
0
15
44
21
26/01/2013 09:00
38.37
38.37
188,844
0
0
0
0
0
0
0
0
0
0
0
70
26/01/2013 10:00
38.38
38.38
189,045
0
0
0
0
0
0
0
0
0
0
0
65
26/01/2013 11:00
38.39
38.38
189,246
0
0
0
0
0
0
0
0
0
0
0
0
26/01/2013 12:00
38.38
38.38
189,045
0
0
0
0
0
0
0
0
0
0
0
0
26/01/2013 13:00
38.38
38.38
189,045
0
0
0
0
0
0
0
0
0
0
0
0
26/01/2013 14:00
38.38
38.39
189,045
0
0
0
0
0
0
0
0
0
0
0
28
26/01/2013 15:00
38.39
38.39
189,246
0
0
0
0
0
0
0
0
0
0
0
65
26/01/2013 16:00
38.40
38.40
189,447
0
0
0
0
0
0
0
0
0
0
0
19
26/01/2013 17:00
38.40
38.40
189,447
0
0
0
0
0
0
0
0
0
0
0
61
26/01/2013 18:00
38.42
38.41
189,850
0
0
0
0
0
0
0
0
0
0
0
65
26/01/2013 19:00
38.42
38.42
189,850
0
0
0
0
0
0
0
0
0
0
0
0
26/01/2013 20:00
38.42
38.43
189,850
1
1
1
1
1
15
15
15
15
15
74
65
26/01/2013 21:00
38.42
38.44
189,850
1
1
1
1
1
15
15
15
15
15
74
144
26/01/2013 22:00
38.44
38.43
190,252
1
1
1
1
1
15
15
15
15
15
74
112
26/01/2013 23:00
38.43
38.44
190,051
1
1
1
1
1
15
15
15
15
15
74
0
27/01/2013 00:00
38.42
38.42
189,850
1
1
1
1
1
15
15
15
15
15
74
74
27/01/2013 01:00
38.43
38.44
190,051
1
1
1
1
1
15
15
15
15
15
74
149
27/01/2013 02:00
38.44
38.44
190,252
1
1
1
1
1
15
15
15
15
15
74
74
27/01/2013 03:00
38.43
38.44
190,051
2
2
2
2
2
37
37
37
37
37
184
114
27/01/2013 04:00
38.42
38.43
189,850
2
2
2
2
2
37
37
37
37
37
183
151
27/01/2013 05:00
38.42
38.43
189,850
2
2
2
2
2
37
37
37
37
37
183
221
27/01/2013 06:00
38.43
38.44
190,051
2
2
2
2
2
37
37
37
37
37
184
212
27/01/2013 07:00
38.43
38.44
190,051
2
2
2
2
2
37
37
37
37
37
184
207
27/01/2013 08:00
38.44
38.44
190,252
2
2
2
2
2
37
37
37
37
37
184
235
27/01/2013 09:00
38.45
38.45
190,453
2
2
2
2
2
37
37
37
37
37
184
296
27/01/2013 10:00
38.48
38.48
191,057
3
3
3
3
3
60
60
60
60
60
302
470
Page 79
Date/time
ALERT
Gauge
Gauge
Boards
Gate settings
Storage
Volume
A B C D
27/01/2013 11:00
E
Gate discharges
Total
Outflow
Total
Inflow
A
B
C
D
E
3
3
3
3
3
m /s
3
m /s
3
m AHD
m AHD
ML
38.51
38.51
191,660
3
3
3
3
3
61
61
61
61
61
303
513
FLOOD EVENT DECLARED
27/01/2013 12:00
38.56
38.55
192,666
3
3
3
3
3
61
61
61
61
61
304
663
27/01/2013 13:00
38.64
38.63
194,275
3
3
3
3
3
61
61
61
61
61
306
837
27/01/2013 14:00
38.75
38.73
196,488
3
3
3
3
3
62
62
62
62
62
309
976
27/01/2013 15:00
38.89
38.90
199,304
3
3
3
3
3
62
62
62
62
62
312
1,387
27/01/2013 16:00
39.12
39.09
204,074
3
3
3
3
3
63
63
63
63
63
317
1,651
27/01/2013 17:00
39.33
39.30
208,549
4
3
4
4
4
91
64
91
91
91
427
1,662
27/01/2013 18:00
39.53
39.50
212,810
4
4
6
4
4
92
92
144
92
92
511
1,548
27/01/2013 19:00
39.67
39.66
215,836
6
4
6
4
6
145
93
145
93
145
621
1,281
27/01/2013 20:00
39.75
39.75
217,589
6
6
6
6
6
146
146
146
146
146
729
1,050
27/01/2013 21:00
39.78
39.80
218,247
6
6
6
6
6
146
146
146
146
146
731
797
27/01/2013 22:00
39.78
39.78
218,247
6
6
8
6
8
146
146
198
146
198
834
835
27/01/2013 23:00
39.78
39.78
218,247
6
6
8
6
8
146
146
198
146
198
834
733
28/01/2013 00:00
39.75
39.76
217,589
6
6
6
6
6
146
146
146
146
146
729
592
28/01/2013 01:00
39.74
39.75
217,370
6
6
6
6
6
146
146
146
146
146
729
668
28/01/2013 02:00
39.73
39.74
217,151
6
6
6
6
6
146
146
146
146
146
728
744
28/01/2013 03:00
39.74
39.74
217,370
6
4
6
4
6
146
93
146
93
146
624
599
28/01/2013 04:00
39.72
39.74
216,932
6
4
6
4
6
146
93
146
93
146
623
517
28/01/2013 05:00
39.71
39.72
216,713
6
4
6
4
6
145
93
145
93
145
622
567
28/01/2013 06:00
39.70
39.71
216,494
6
4
6
4
6
145
93
145
93
145
622
556
28/01/2013 07:00
39.69
39.69
216,274
6
4
6
4
6
145
93
145
93
145
621
591
28/01/2013 08:00
39.69
39.70
216,274
6
4
6
4
6
145
93
145
93
145
621
632
28/01/2013 09:00
39.69
39.70
216,274
6
4
6
4
6
145
93
145
93
145
621
601
28/01/2013 10:00
39.68
39.68
216,055
6
4
6
4
6
145
93
145
93
145
621
489
28/01/2013 11:00
39.65
39.66
215,398
6
4
6
4
6
145
93
145
93
145
620
482
28/01/2013 12:00
39.63
39.64
214,959
6
4
6
4
6
145
93
145
93
145
619
333
28/01/2013 13:00
39.56
39.59
213,450
6
4
6
4
6
144
92
144
92
144
616
307
28/01/2013 14:00
39.53
39.50
212,810
6
4
6
4
6
144
92
144
92
144
614
368
28/01/2013 15:00
39.47
39.48
211,532
6
4
6
4
6
143
92
143
92
143
612
247
28/01/2013 16:00
39.41
39.40
210,253
6
4
6
4
6
142
91
142
91
142
609
229
28/01/2013 17:00
39.34
39.35
208,762
6
4
6
4
6
141
91
141
91
141
606
152
28/01/2013 18:00
39.26
39.27
207,057
6
4
6
4
6
141
90
141
90
141
602
158
28/01/2013 19:00
39.19
39.20
205,566
6
4
6
4
6
140
90
140
90
140
599
155
28/01/2013 20:00
39.11
39.12
203,861
6
4
6
4
6
139
89
139
89
139
595
151
28/01/2013 21:00
39.04
39.04
202,369
6
4
6
4
6
138
89
138
89
138
592
154
28/01/2013 22:00
38.96
39.00
200,712
4
4
4
4
4
88
88
88
88
88
441
7
28/01/2013 23:00
38.89
38.90
199,304
4
3
4
3
4
88
62
88
62
88
388
17
29/01/2013 00:00
38.83
38.85
198,097
3
3
3
3
3
62
62
62
62
62
311
59
29/01/2013 01:00
38.80
38.80
197,494
2
2
3
2
2
38
38
62
38
38
213
78
29/01/2013 02:00
38.78
38.80
197,091
1
1
2
1
2
15
15
38
15
38
121
70
29/01/2013 03:00
38.78
38.80
197,091
1
1
1
1
1
15
15
15
15
15
76
85
29/01/2013 04:00
38.78
38.80
197,091
1
1
1
1
1
15
15
15
15
15
76
71
29/01/2013 05:00
38.78
38.80
197,091
0
0
1
0
0
0
0
15
0
0
15
39
29/01/2013 06:00
38.79
38.80
197,293
0
0
0
0
0
0
0
0
0
0
0
93
29/01/2013 07:00
38.81
38.81
197,695
0
0
0
0
0
0
0
0
0
0
0
93
29/01/2013 08:00
38.82
38.81
197,896
0
0
0
0
0
0
0
0
0
0
0
19
29/01/2013 09:00
38.82
38.82
197,896
0
0
0
0
0
0
0
0
0
0
0
24
29/01/2013 10:00
38.83
38.83
198,097
0
0
0
0
0
0
0
0
0
0
0
65
29/01/2013 11:00
38.84
38.84
198,298
0
0
0
0
0
0
0
0
0
0
0
24
29/01/2013 12:00
38.84
38.84
198,298
0
0
0
0
0
0
0
0
0
0
0
28
29/01/2013 13:00
38.85
38.85
198,500
0
0
0
0
0
0
0
0
0
0
0
28
29/01/2013 14:00
38.85
38.85
198,500
0
0
0
0
0
0
0
0
0
0
0
28
29/01/2013 15:00
38.86
198,701
0
0
0
0
0
0
0
0
0
0
0
28
29/01/2013 16:00
38.86
198,701
0
0
0
0
0
0
0
0
0
0
0
24
Page 80
Date/time
ALERT
Gauge
Gauge
Boards
Gate settings
Storage
Volume
A B C D
m AHD
m AHD
ML
E
Gate discharges
Total
Outflow
Total
Inflow
A
B
C
D
E
3
3
3
3
3
m /s
3
m /s
3
29/01/2013 17:00
38.87
198,902
0
0
0
0
0
0
0
0
0
0
0
61
29/01/2013 18:00
38.88
199,103
0
0
0
0
0
0
0
0
0
0
0
61
29/01/2013 19:00
38.89
199,304
0
0
0
0
0
0
0
0
0
0
0
28
29/01/2013 20:00
38.89
199,304
0
0
0
0
0
0
0
0
0
0
0
0
29/01/2013 21:00
38.89
199,304
0
0
0
0
0
0
0
0
0
0
0
0
29/01/2013 22:00
38.89
199,304
0
0
0
0
0
0
0
0
0
0
0
33
29/01/2013 23:00
38.90
199,505
0
0
0
0
0
0
0
0
0
0
0
33
30/01/2013 00:00
38.90
199,505
0
0
0
0
0
0
0
0
0
0
0
0
30/01/2013 01:00
38.90
199,505
0
0
0
0
0
0
0
0
0
0
0
33
30/01/2013 02:00
38.91
199,707
0
0
0
0
0
0
0
0
0
0
0
33
30/01/2013 03:00
38.91
199,707
0
0
0
0
0
0
0
0
0
0
0
0
30/01/2013 04:00
38.91
199,707
0
0
0
0
0
0
0
0
0
0
0
33
30/01/2013 05:00
38.92
199,908
0
0
0
0
0
0
0
0
0
0
0
33
30/01/2013 06:00
38.92
199,908
0
0
0
0
0
0
0
0
0
0
0
0
30/01/2013 07:00
38.92
199,908
0
0
0
0
0
0
0
0
0
0
0
33
30/01/2013 08:00
38.93
200,109
0
0
0
0
0
0
0
0
0
0
0
33
30/01/2013 09:00
38.93
200,109
0
0
0
0
0
0
0
0
0
0
0
0
Page 81
Blank page
Page 82
APPENDIX D. SITUATION REPORTS
Page 83
Flood Operations Centre
Situation Report (SitRep)
SEQWATER FLOOD OPERATIONS CENTRE
SITUATION REPORT NO 1
The information and analysis contained in this report is based on data and
forecasts available at the time of issue. As circumstances can change rapidly,
reference should always be made to the most recent Situation Report update.
Date
25 January 2013
Time
15:30
Duty
Engineer
The Flood Operations Centre was mobilised at 12:00 on 25 January 2013.
Current Operational Situation
No flood releases are occurring from Wivenhoe Dam.
No flood releases are occurring from Somerset Dam.
No flood releases are occurring from North Pine Dam.
No flood releases are occurring from Leslie Harrison Dam.
Rainfall (current, forecast, warnings)
QUANTITATIVE PRECIPITATION FORECAST FOR SEQWATER Issued at
10:40am EST on Friday the 25th of January 2013 by the BUREAU OF
METEOROLOGY.
SOMERSET DAM AND WIVENHOE DAM CATCHMENTS:
Forecast of estimated catchment average rainfall for the 24 hour period to 10
AM SATURDAY: 50 - 100 mm, with isolated heavier falls in excess of 100mm
through northern stretches of the catchment.
NORTH PINE DAM CATCHMENT Forecast of estimated catchment average
rainfall for the 24 hour period to 10 AM SATURDAY: 100 - 150 mm.
Three day forecasts for the catchment areas indicate rainfall totals in the order
of 200 mm to 300 mm.
The controlled version of this document is registered. All other versions are uncontrolled
Page: 1 of 5
North Pine Dam
Current Strategy
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Water will be drawn down from North Pine
Dam from today as a result of forecast heavy
rain associated with Ex Tropical Cyclone
Oswald that is expected to impact on southeast Queensland over the Australia Day long
weekend. A Temporary Full Supply Level has
been declared for North Pine Dam and the
dam is to be lowered to this level in preparation
for the anticipated heavy rain. The North Pine
Dam lake level is currently EL 38.76 metres
(91.7%). The temporary Full Supply Level is
EL 38.40 (88.0%). To achieve this reduced
level, releases from the dam will commence at
approximately 8:00pm tonight and continue
through to Saturday.
Changes to water
releases from the dam will depend on how
rainfall develops across the catchment over the
long weekend.
Impacts
Bridges
o Young’s Crossing
o A. J. Wylie
Other streams
o Sideling Creek Dam
Young’s Crossing will be closed for the
duration of the release.
Discussions with Councils and
State agencies
Moreton Bay Regional Council will close
Young’s Crossing prior to the commencement
of the release.
Possible Developments
Rain outlook
Strategies
At 10am EST, Ex Tropical Cyclone Oswald
was located over the central interior of
Queensland around 50km east of Moranbah
and moving south southeast at around 15
km/h. A trough extends from Ex Tropical
Cyclone Oswald to the southern Capricornia
coast. The trough and low are expected to
continue moving south, reaching southeast
districts on Sunday. Three day forecasts for
the catchment areas indicate rainfall totals in
the order of 200 mm to 300 mm.
Page: 2 of 5
Somerset/Wivenhoe Dams
Overall Strategy
Water will be drawn down from Wivenhoe Dam
today as a result of forecast heavy rain
associated with Ex Tropical Cyclone Oswald
that is expected to impact on south-east
Queensland over the Australia Day long
weekend. A Temporary Full Supply level has
been declared for Wivenhoe Dam and the dam
is to be lowered to this level in preparation for
the anticipated heavy rain. No change has
been made to the Somerset Dam Full Supply
level.
Somerset Dam - Current Situation
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating strategy
Somerset Dam lake level is currently EL 98.70
metres (96.7%). Releases from the dam will
not commence until the lake level exceeds EL
99.00 metres. Depending on rainfall, this may
not occur until sometime on Saturday.
Wivenhoe Dam - Current Situation
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and Peak)
Operating Strategy
Impacts
Bridges
o Mary Smokes Bridge
o Twin Bridges
o Fernvale Bridge
o Savages Crossing
o Burtons Bridge
o Kholo Bridge
o Mt Crosby Bridge
o Colleges Crossing
Other streams
o Lockyer Creek
o Bremer River
Threshold for damaging
flows
Tides
Wivenhoe Dam lake level is currently EL 66.06
metres (91.6%). The temporary Full Supply
Level is EL 65.60 (88.0%). To achieve this
reduced level, releases from the dam will
commence at approximately 4:00pm this
afternoon and continue through to Saturday.
Changes to water releases from the dam will
depend on how rainfall develops across the
dam catchments over the long weekend.
The releases will initially close Twin Bridges,
Savages Crossing and Colleges Crossing.
Further operational impacts will depend on
how rainfall develops across the dam
catchments over the long weekend.
Page: 3 of 5
State agencies
Somerset Regional Council will close Twin
Bridges and Savages Crossing prior to these
bridges being inundated by the release.
The Department of Main Roads will close
Colleges Crossing prior to this bridge being
inundated by the release.
The Brisbane City Council and the Ipswich City
Council have been notified of the release.
Rain outlook & forecasts
Strategies
At 10am EST, Ex Tropical Cyclone Oswald
was located over the central interior of
Queensland around 50km east of Moranbah
and moving south southeast at around 15
km/h. A trough extends from Ex Tropical
coast. The trough and low are expected to
continue moving south, reaching southeast
districts on Sunday. Three day forecasts for
the catchment areas indicate rainfall totals in
the order of 200 mm to 300 mm.
The predictions incorporated into this Situation Report
are based on Quantitative Precipitation Forecasts
(QPFs), produced by the Bureau of Meteorology, that
have then been varied by Seqwater to take account of
actual recorded rainfall for the forecast period.
Leslie Harrison Dam
Leslie Harrison Dam - Current
Situation
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating strategy
Leslie Harrison Dam lake level is currently
EL 17.34 metres (82.7%).
The potential
impacts of Ex Tropical Cyclone Oswald on the
dam are currently being assessed and a
decision will be made on the need to
commence releases later today.
This Situation Report has been provided to the following organisations:
Maritime Safety Queensland
Emergency Management Queensland and State Disaster Coordination Centre
Department of Energy and Water Supply
Department of Transport and Main Roads
Water Grid Manager
Queensland Police Service and the District Disaster Management Group
Page: 4 of 5
Next Situation Report Due
Before 8:00pm on 25 January 2013
Disclaimer: Seqwater has prepared this Situation Report using sources of information available to it at
the time and date of issue. Data available to Seqwater in real time may not have been independently
verified. Seqwater assumes no responsibility for any inaccuracies or omissions.
Parties who receive this Situation Report must make and rely on their own enquiries and professional
advice in relation to, and in evaluation of, anything contained in this Situation Report.
The information and analysis in this Situation Report, including estimates and forecasts, may be subject
to rapid change (whether or not material) without notice.
Page: 5 of 5
Date
25 January 2013
Time
20:00
Duty
Engineer
Flood releases are occurring from Wivenhoe Dam.
Flood releases are occurring from North Pine Dam.
4:00pm EST on Friday the 25th of January 2013 by the BUREAU OF
METEOROLOGY.
Forecast of estimated catchment average rainfall for the 24 hour period to 4pm
SATURDAY: 75 -150 mm, with isolated heavier falls in excess of 150mm
NORTH PINE DAM CATCHMENT:
SATURDAY: 150 -250 mm.
Page: 1 of 5
North Pine Dam
Current Strategy
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Water will be drawn down from North Pine
Dam from today as a result of forecast heavy
rain associated with Ex Tropical Cyclone
Oswald that is expected to impact on South
East Queensland over the Australia Day long
dam is to be lowered to this level in preparation
for the anticipated heavy rain. The North Pine
Dam lake level is currently EL 38.76 metres
(91.7%). The temporary Full Supply Level is
EL 38.40 (88.0%). To achieve this reduced
level, releases from the dam will commence at
approximately 8:00pm tonight and continue
through to Saturday.
Changes to water
releases from the dam will depend on how
rainfall develops across the catchment over the
long weekend.
Impacts
Bridges
o A. J. Wylie
Other streams
Young’s Crossing will be closed for the
duration of the release.
State agencies
Moreton Bay Regional Council will close
Young’s Crossing prior to the commencement
of the release.
Rain outlook
Strategies
At 4pm EST, Ex Tropical Cyclone Oswald was
located over the central interior of Queensland
around 100km north-east of Emerald and
160km west north-west of Rockhampton,
moving south south-east at around 15 km/h.
Heavy rainfall which may lead to flash flooding
is expected over areas of the Southeast Coast
district north of Brisbane for the remainder of
today, extending through remaining parts of
the Southeast Coast district late tonight or
early Saturday.
Page: 2 of 5
Overall Strategy
Water will be drawn down from Wivenhoe Dam
today as a result of forecast heavy rain
that is expected to impact on South East
weekend. A Temporary Full Supply level has
been declared for Wivenhoe Dam and the dam
is to be lowered to this level in preparation for
the anticipated heavy rain. No change has
been made to the Somerset Dam Full Supply
level.
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating strategy
not commence until the lake level exceeds at
least EL 99.00 metres. Depending on rainfall,
this may not occur until sometime on Saturday.
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and Peak)
Operating Strategy
Impacts
Bridges
o Twin Bridges
o Fernvale Bridge
o Savages Crossing
o Burtons Bridge
o Kholo Bridge
o Mt Crosby Bridge
o Colleges Crossing
Other streams
o Lockyer Creek
o Bremer River
flows
Tides
Level is EL 65.60 (88.0%). To achieve this
reduced level, releases from the dam
commenced at 4:00pm this afternoon and will
continue through to Saturday. Changes to
water releases from the dam will depend on
The releases will initially close Twin Bridges,
Savages Crossing and Colleges Crossing.
Further operational impacts will depend on
Page: 3 of 5
State agencies
Somerset Regional Council has closed Twin
Bridges and Savages Crossing.
Colleges Crossing tomorrow morning prior to
this bridge being inundated by the release.
Strategies
At 4pm EST, Ex Tropical Cyclone Oswald was
located over the central interior of Queensland
around 100km north-east of Emerald and
160km west north-west of Rockhampton,
moving south south-east at around 15 km/h.
Heavy rainfall which may lead to flash flooding
is expected over areas of the Southeast Coast
district north of Brisbane for the remainder of
today, extending through remaining parts of
the Southeast Coast district late tonight or
early Saturday.
Leslie Harrison Dam
Situation
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating strategy
EL 17.34 metres (82.7%).
The potential
dam are being assessed on an ongoing basis
releases from the dam will be initiated if
required.
Operational personnel are on site and ready to
commence operations if necessary.
The Bureau Of Meteorology have advised that
water levels on the high tide are likely to
exceed the highest tide of the year during
Saturday and Sunday which may cause
flooding of some low lying areas. The impact
of these tides will be considered when
formulating a release strategy from the dam.
Water Grid Manager
Page: 4 of 5
Before 8:00am on 26 January 2013
Page: 5 of 5
Date
26 January 2013
Time
07:30
Duty
Engineer
Flood releases are occurring from Wivenhoe Dam.
Flood releases are occurring from North Pine Dam.
4:00pm EST on Friday the 25th of January 2013 by the BUREAU OF
METEOROLOGY.
SATURDAY: 75 -150 mm, with isolated heavier falls in excess of 150mm
NORTH PINE DAM CATCHMENT:
SATURDAY: 150 -250 mm.
The BUREAU OF METEOROLOGY advised at 5:09am EST on Saturday the
26th of January 2013 that rainfall totals of 200mm (up to 350mm in elevated
areas), are forecast for coastal areas during Saturday with the heaviest rainfall
between Gladstone and Bundaberg. Rainfall totals of 50-100mm are forecast
for areas further inland. Similar rainfall totals are expected for the remainder of
the weekend as the system moves southward.
Page: 1 of 5
North Pine Dam
Current Strategy
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Water has been drawn down from North Pine
Dam in preparation for the forecast heavy rain
dam has been lowered to near this level. The
North Pine Dam lake level is currently
EL 38.38 metres (88.2%). Releases will cease
at 8:15am this morning to allow Young’s
Crossing to be opened during today. It is
expected that releases will need to
recommence later today or tonight as further
rail falls across the catchment.
Impacts
Bridges
o A. J. Wylie
Other streams
Young’s Crossing will be opened this morning
as soon as it is clear of water. This will occur
sometime after 8:15am when the current
release from the dam ceases. If releases
recommence, Young’s Crossing will reclose
and remain closed for the duration of the
release.
State agencies
Moreton Bay Regional Council will open
Young’s Crossing this morning as soon as it is
clear of water. The Council will reclose the
crossing if releases recommence.
Rain outlook
Strategies
At 4am EST today, Ex Tropical Cyclone
Oswald remains slow moving over the Central
Highlands, about 100km northeast of Emerald
and 160km west northwest of Rockhampton.
Ex Tropical Cyclone Oswald is expected to
begin moving towards the south southeast
later today. A trough extends from Ex Tropical
coast. Heavy rainfall which may lead to flash
flooding is expected over the Wide Bay and
Burnett district, extending through the
Southeast Coast and eastern parts of the
Darling Downs and Granite Belt districts
tonight. Six hour rainfall accumulations in
excess of 100mm are likely.
Page: 2 of 5
Overall Strategy
Water is being drawn down from Wivenhoe
Dam as a result of forecast heavy rain
been declared for Wivenhoe Dam. No change
has been made to the Somerset Dam Full
Supply level.
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating strategy
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and Peak)
Operating Strategy
Impacts
Bridges
o Twin Bridges
o Fernvale Bridge
o Savages Crossing
o Burtons Bridge
o Kholo Bridge
o Mt Crosby Bridge
o Colleges Crossing
Other streams
o Lockyer Creek
o Bremer River
flows
Tides
this may not occur until later today or
tomorrow.
Level is EL 65.60 (88.0%). Releases from the
dam commenced at 4:00pm yesterday
afternoon and are continuing. Changes to
water releases from the dam will depend on
The releases from Wivenhoe Dam have closed
Twin Bridges and Savages Crossing. Colleges
Crossing will be closed later this morning
(around 10:00am) as water from the release
that commenced yesterday reaches the
crossing.
Future operational impacts will
Page: 3 of 5
State agencies
Somerset Regional Council has closed Twin
Bridges and Savages Crossing.
Colleges Crossing this morning (around
10:00am) prior to this bridge being inundated
by the release.
Strategies
At 4am EST today, Ex Tropical Cyclone
Oswald remains slow moving over the Central
Highlands, about 100km northeast of Emerald
and 160km west northwest of Rockhampton.
Ex Tropical Cyclone Oswald is expected to
begin moving towards the south southeast
later today. A trough extends from Ex Tropical
coast. Heavy rainfall which may lead to flash
flooding is expected over the Wide Bay and
Burnett district, extending through the
Southeast Coast and eastern parts of the
Darling Downs and Granite Belt districts
tonight. Six hour rainfall accumulations in
excess of 100mm are likely.
Leslie Harrison Dam
Situation
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating strategy
EL 17.39 metres (83.5%).
The potential
dam are being assessed on an ongoing basis,
and releases from the dam will be initiated if
considered necessary. Catchment average
rainfall over the last 24 hours is 47 millimetres.
Runoff into the dam is minimal.
Page: 4 of 5
Water Grid Manager
Page: 5 of 5
Date
26 January 2013
Time
22:00
Duty
Engineer
• Releases are occurring from Wivenhoe Dam.
• No flood releases are occurring from Somerset Dam.
• Releases are occurring from North Pine Dam.
• No flood releases are occurring from Leslie Harrison Dam.
4:27pm EST on Saturday the 26th of January 2013
Forecast of estimated catchment average rainfall for the 24 hour period to
4pm SUNDAY: 100 to 200mm.
NORTH PINE DAM CATCHMENT
4pm SUNDAY: 150 - 250 mm.
Page: 1 of 5
North Pine Dam
Current Strategy
• Dam levels
(current and peak)
• Dam volumes
• Gate status
• Inflows
• Releases
(current and peak)
weekend. A Temporary Full Supply Level of
38.4m has been declared for North Pine Dam
and the dam has been lowered to near this
level.
The North Pine Dam lake level is currently
EL 38.44 metres (88.8%).
Releases have
recommenced this evening to maintain the
level at about the declared FSL, with a current
release of approximately 80 m3/s. Releases will
continue overnight, with an anticipated
maximum release of less than 300 m3/s. An
assessment will be made in the morning about
whether releases will continue tomorrow
depending on dam levels and actual and
anticipated rainfall.
Impacts
• Bridges
o A. J. Wylie
• Other streams
Young’s Crossing is closed at present. Young’s
Crossing may open tomorrow morning
depending on dam levels and actual and
anticipated rainfall.
State agencies
Discussions have been held with Moreton Bay
Regional Council regarding the closure of
Young’s Crossing.
• Rain outlook
• Strategies
The Bureau advised late this afternoon that the
current steady rainfall over North Pine Dam
would likely continue overnight and tomorrow
morning, with the heavy rainfall starting
tomorrow afternoon. The overall strategy at
this stage is to maintain the dam near the
declared temporary FSL in preparation for the
expected heavy rainfall.
Page: 2 of 5
Overall Strategy
The level in Wivenhoe Dam is being drawn
down as a result of forecast heavy rain
been declared for Wivenhoe Dam. No change
has been made to the Somerset Dam Full
Supply level.
• Dam levels
(current and peak)
• Dam volumes
• Gate status
• Inflows
• Releases
(current and peak)
• Operating strategy
• Dam levels
(current and peak)
• Dam volumes
• Gate status
• Inflows
• Releases
(current and Peak)
• Operating Strategy
this may not occur until tomorrow afternoon.
Impacts
• Bridges
o Twin Bridges
o Fernvale Bridge
o Savages Crossing
o Burtons Bridge
o Kholo Bridge
o Mt Crosby Bridge
o Colleges Crossing
• Other streams
o Lockyer Creek
o Bremer River
Level is EL 65.6 (88.0%). Releases from the
dam commenced at 4:00pm on 24/1/13 and
are
continuing.
Current
releases
are
approximately 400 m3/s. Releases are planned
to be increased overnight with the aim of
reducing the dam level to approximately the
declared temporary full supply level at around
midday tomorrow, in preparation for the heavy
rainfall expected tomorrow afternoon. The
maximum release is expected to be less than
about 1500 m3/s. The situation will continue to
be monitored and the actual releases will
depend on dam levels, actual and anticipated
rainfall and streamflow above and below the
dams.
Twin Bridges, Savages Crossing and Colleges
Crossing. Increasing releases overnight will
inundate Burtons and Kholo Bridge tomorrow
morning. Future operational impacts will
Page: 3 of 5
•
flows
• Tides
State agencies
• Rain outlook & forecasts
• Strategies
Discussions have been held with Somerset
Burtons Bridge. SRC have advised that
affected residents have been contacted.
Discussions have been held with Ipswich City
Council and Brisbane City Council regarding
the closure of Kholo Bridge early tomorrow
morning.
The Bureau advised late this afternoon that the
current steady rainfall over Somerset and
Wivenhoe Dams would likely continue
overnight and tomorrow morning, with the
heavy rainfall starting tomorrow afternoon. The
overall strategy at this stage is to increase
releases from Wivenhoe to reduce the dam
level to near the declared temporary FSL in
preparation for the expected heavy rainfall
tomorrow afternoon, with releases below
around 1500 m3/s which keeps Mt Crosby
Bridge and Fernvale Bridge open and is below
the rate that causes significant property
damage.
Leslie Harrison Dam
Situation
• Dam levels
(current and peak)
• Dam volumes
• Gate status
• Inflows
• Releases
(current and peak)
EL 17.16 metres (79.7%).
The potential
considered necessary. Dam levels over the
past 6 hours have been steady. Runoff into
the dam is minimal.
Page: 4 of 5
• Somerset Regional Council
• Ipswich City Council
• Moreton Bay Regional Council
• Brisbane City Council
• Redland City Council
• Maritime Safety Queensland
• Emergency Management Queensland and State Disaster Coordination Centre
• Department of Energy and Water Supply
• Department of Transport and Main Roads
• Bureau of Meteorology
• Water Grid Manager
• Queensland Police Service and the District Disaster Management Group
~7:00am on 27 January 2013
Page: 5 of 5
Date
27 January 2013
Time
06:00
Duty
Engineer
• No flood releases are occurring from Somerset Dam.
• No flood releases are occurring from Leslie Harrison Dam.
QUANTITATIVE PRECIPITATION FORECAST FOR SEQWATER Issued at 4:27pm EST on
Saturday the 26th of January 2013
4pm SUNDAY: 100 to 200mm.
4pm SUNDAY: 150 - 250 mm.
FLOOD WARNING FOR COASTAL RIVERS AND ADJACENT INLAND CATCHMENTS
FROM ROCKHAMPTON TO THE NSW BORDER Issued at 5:36 am EST on Sunday 27
January 2013 by the Bureau of Meteorology, Brisbane
Widespread moderate to heavy rainfall continues in the coastal catchments from Rockhampton
down to the Gold Coast area during early Sunday, with the heaviest rainfall between
Bundaberg and Brisbane.
Moderate to heavy rainfall is forecast to continue in the warning area till late Monday, with 24
hour rainfall totals in excess of 250mm likely.
Fast river and creek rises are occurring or expected in the coastal rivers and streams within the
warning area over the weekend.
Flood warnings remain current for the Boyne, Calliope, Baffle and Kolan River catchments, the
Burnett, the Connors, Isaac, Don, Lower Dawson and Fitzroy Rivers within the Fitzroy
catchment, the Cherwell-Burrum Rivers, and the Mary River.
Flooding is possible the Noosa River, Maroochy and Mooloolaba Rivers, Pine and Caboolture
Rivers, Brisbane River, and the Brisbane Metropolitan Creeks.
Warnings for these catchments will be issued if required.
A severe weather warning for heavy rainfall is current for the warning area.
Page: 1 of 5
North Pine Dam
Current Strategy
• Dam levels
(current and peak)
• Dam volumes
• Gate status
• Inflows
• Releases
(current and peak)
weekend. A Temporary Full Supply Level of
38.4m has been declared for North Pine Dam
and the dam has been lowered to near this
level.
EL 38.43 metres (88.7%). Current releases are
approximately 180 m3/s. Releases are
expected to continue into the afternoon today,
when heavy rainfall is expected.
Impacts
• Bridges
o A. J. Wylie
• Other streams
Young’s Crossing is closed at present and is
not expected to open today owing to the heavy
rainfall expected this afternoon.
State agencies
Young’s Crossing.
• Rain outlook
• Strategies
The Bureau advised late afternoon yesterday
that the light steady rainfall over North Pine
Dam would likely continue this morning, with
the heavy rainfall starting in the afternoon
today. The overall strategy at this stage is to
maintain the dam near the declared temporary
FSL in preparation for the expected heavy
rainfall.
Page: 2 of 5
Overall Strategy
The level in Wivenhoe Dam is being drawn
down as a result of forecast heavy rain
been declared for Wivenhoe Dam at EL 65.6
(88.0%). No change has been made to the
Somerset Dam Full Supply level.
• Dam levels
(current and peak)
• Dam volumes
• Gate status
• Inflows
• Releases
(current and peak)
metres (99.8%). Current inflows are estimated
at 300 m3/s. No releases are currently being
made. Minor releases may be made through
the regulators later this morning to maintain the
dam near FSL.
The situation will continue to be monitored and
the actual releases will depend on dam levels,
actual and anticipated rainfall and streamflow
above and below the dams.
• Dam levels
(current and peak)
• Dam volumes
• Gate status
• Inflows
• Releases
(current and peak)
metres (88.2%). Releases from the dam
commenced at 4:00pm on 24/1/13 and are
continuing. Current releases are approximately
900 m3/s. Releases will be managed to
maintain the dam at about the declared
temporary FSL in preparation for the heavy
rainfall expected tomorrow afternoon.
The situation will continue to be monitored and
the actual releases will depend on dam levels,
actual and anticipated rainfall and streamflow
above and below the dams.
Impacts
• Bridges
o Twin Bridges
o Fernvale Bridge
o Savages Crossing
o Burtons Bridge
o Kholo Bridge
o Mt Crosby Bridge
o Colleges Crossing
• Other streams
o Lockyer Creek
o Bremer River
• Threshold for damaging
flows
• Tides
Twin Bridges, Savages Crossing, Colleges
Crossing, Burtons Bridge and Kholo Bridge. All
bridges are expected to remain closed until the
afternoon, when heavy rainfall is expected.
Should the prospect of heavy rainfall diminish
or be delayed, it may be possible to re-open
some bridges later today.
Conditions will continue to be monitored and
updates will be provided as the situation
becomes clear.
Page: 3 of 5
State agencies
Somerset Regional Council has confirmed that
Burtons Bridge is closed.
Brisbane City Council have advised their side
of Kholo Bridge has been closed, and similar
advice from Ipswich City Council is expected
this morning.
• Strategies
The Bureau advised late afternoon yesterday
that the light steady rainfall over Somerset and
Wivenhoe Dams would likely continue this
morning, with the heavy rainfall starting this
afternoon. The overall strategy at this stage is
to maintain Wivenhoe and Somerset near their
current FSLs in preparation for the expected
heavy rainfall this afternoon.
Leslie Harrison Dam
Situation
• Dam levels
(current and peak)
• Dam volumes
• Gate status
• Inflows
• Releases
(current and peak)
EL 17.43 metres (84.2%). The potential
considered necessary. Runoff into the dam in
this event so far has been minimal.
Page: 4 of 5
~7:00pm on 27 January 2013
Page: 5 of 5
Date
27 January 2013
Time
12:00
Duty
Engineer
Releases are occurring from Wivenhoe Dam.
Releases are occurring from Somerset Dam.
Releases are occurring from North Pine Dam.
Releases are occurring from Leslie Harrison Dam.
QUANTITATIVE PRECIPITATION FORECAST FOR SEQWATER Issued at 10:03am EST
on Sunday the 27th of January 2013
Forecast of estimated catchment average rainfall for the 24 hour period
to
10am MONDAY: 100 - 200mm.
to
10am MONDAY: 200 - 300 mm.
Page: 1 of 5
North Pine Dam
Current Strategy
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Releases are being made from North Pine
that is currently impacting South East
Queensland. A Temporary Full Supply Level
of 38.4m has been declared for North Pine
Dam and the dam has been lowered to near
this level.
EL 38.51 metres. Current releases are
expected to continue through to at least
tomorrow.
Impacts
Bridges
o A. J. Wylie
Other streams
State agencies
not expected to open today.
Rain outlook
Strategies
The overall strategy is to minimise downstream
disruption caused by the releases.
Young’s Crossing.
Page: 2 of 5
Overall Strategy
Releases are being made from Wivenhoe Dam
as a result of forecast heavy rain associated
with Ex Tropical Cyclone Oswald that is
currently impacting South East Queensland. A
Temporary Full Supply Level has been
declared for Wivenhoe Dam of EL 65.6 metres.
No change has been made to the Somerset
Dam Full Supply level.
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating strategy
metres and rising rapidly. Releases through
the regulators have commenced and further
releases are likely later today.
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating Strategy
Wivenhoe Dam lake level is currently
EL 65.63. Releases from the dam commenced
at 4:00pm on 25/1/13 and are continuing.
Releases are currently being increased and
are now approximately 1100 m3/s.
Impacts
Bridges
o Twin Bridges
o Fernvale Bridge
o Savages Crossing
o Burtons Bridge
o Kholo Bridge
o Mt Crosby Bridge
o Colleges Crossing
Other streams
o Lockyer Creek
o Bremer River
flows
Tides
Crossing, Burtons Bridge and Kholo Bridge.
Consideration is currently being given to
closing Mt Crosby Weir Bridge and Fernvale
Bridge.
The projected peak inflow into Wivenhoe Dam
(excluding Somerset Dam outflows) is currently
5200 m3/s based only on the rainfall observed
on the ground. With the rainfall on the ground,
the Wivenhoe lake level should approach
EL 70. Higher levels are possible, depending
upon the rainfall.
Page: 3 of 5
State agencies
Closures for the inundated bridges have been
confirmed with Councils. Discussions are to
commence in relation to the possible closure of
Mt Crosby Weir Bridge and Fernvale Bridge.
Strategies
Further heavy rain is expected and the focus is
changing from lowering the lake level towards
the Temporary Full Supply Level to managing
the flood inflow. A suitable transition strategy
for this change has been approved by DEWS
and a Flood Event has been declared in
accordance with the provisions of Section 8 of
the Manual.
Leslie Harrison Dam
Situation
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating strategy
Seqwater advises that controlled gate releases
from Leslie Harrison Dam have now
commenced through one gate at a rate of four
(4) cubic metres per second. Releases are
expected to continue throughout today, and
may increase depending on rainfall.
Page: 4 of 5
Page: 5 of 5
Date
27 January 2013
Time
16:00
Duty
Engineer
No releases are occurring from Somerset Dam.
Sunday the 27th of January 2013
to 4pm MONDAY: 35 mm.
to 4pm MONDAY: 40 - 60 mm.
Page: 1 of 5
North Pine Dam
Current Strategy
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
A Temporary Full Supply Level of 38.4m was
declared for North Pine Dam and the dam was
lowered to that level in preparation for the
forecast heavy rain associated with Ex Tropical
Cyclone Oswald that is currently impacting
South East Queensland.
EL 38.90 metres. Current releases are
expected to continue through to at least
tomorrow. The lake level is currently rising
rapidly and releases rates are expected to
increase substantially over the next 6 to 12
hours.
Impacts
Bridges
o A. J. Wylie
Other streams
State agencies
Rain outlook
Strategies
Young’s Crossing.
Page: 2 of 5
Overall Strategy
declared for Wivenhoe Dam and the dam was
South East Queensland. No change has been
made to the Somerset Dam Full Supply level.
A Flood Event was declared at 12:00 today in
the Manual. A transition strategy to move from
dam lowering operations to flood operations
was approved by DEWS.
The current strategy in use is W2. Releases
from Wivenhoe Dam will be decreased to allow
flood peaks emanating from Lockyer Creek
and the Bremer River to pass through
Brisbane. Once the peaks have passed,
releases from Wivenhoe Dam will be increased
to allow the flood waters stored in the dams to
be drained.
The rapid southward movement of the rainfall
system that has been observed in recent hours
has caused this revised strategy to be
adopted.
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating strategy
Somerset Dam lake level is currently
EL 100.34 metres and rising rapidly. Water is
currently being held in Somerset Dam,
however releases will recommence later today
as the lake level increases.
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating Strategy
Releases are now being steadily decreased
and are currently 850 m3/s.
(excluding Somerset Dam outflows) is currently
5500 m3/s based only on the rainfall observed
on the ground. With the rainfall on the ground,
the Wivenhoe lake level should approach
EL 70. Higher levels are possible, depending
upon the rainfall.
Page: 3 of 5
Impacts
Bridges
o Twin Bridges
o Fernvale Bridge
o Savages Crossing
o Burtons Bridge
o Kholo Bridge
o Mt Crosby Bridge
o Colleges Crossing
Other streams
o Lockyer Creek
o Bremer River
flows
Tides
Mt Crosby Weir Bridge and Fernvale Bridge
may be closed tomorrow due to flows into the
Brisbane River from Lockyer Creek and
catchments below the dam. Whether these
bridges close will depend on rainfall over the
next 12 hours, particularly in the Lockyer
catchment.
State agencies
confirmed with Councils.
Strategies
The most recent advice from BoM is for
catchment averages of 35mm above Wivenhoe
Dam and 100mm below Wivenhoe Dam over
the next 24 hours. The rainfall system appears
to be moving southwards and is forecast to
substantially clear the dam catchment areas by
Tuesday.
Leslie Harrison Dam
Situation
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating strategy
commenced through two gates at a rate of
eight cubic metres per second. Releases are
expected to continue throughout today, and
may increase further depending on rainfall.
Page: 4 of 5
Page: 5 of 5
Date
27 January 2013
Time
21:30
Duty
Engineer
Page: 1 of 5
North Pine Dam
Current Strategy
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
accordance with the provisions of the Manual.
The flood is classified as large under the
Manual, with dam inflows approaching
1300m3/s.
EL 39.80 metres and rising. Current releases
are approximately 840m3/s. Releases are
expected to increase further over the next six
hours due to rainfall currently being
experienced in the catchment. Releases will
continue through to at least tomorrow.
Impacts
Bridges
o A. J. Wylie
Other streams
State agencies
Rain outlook
Strategies
Young’s Crossing.
Page: 2 of 5
Overall Strategy
South East Queensland. No change has been
made to the Somerset Dam Full Supply level.
the Manual. A transition strategy to move from
dam lowering operations to flood operations
was approved by DEWS.
from Wivenhoe Dam are being decreased to
allow flood peaks emanating from Lockyer
Creek and the Bremer River to pass through
be drained.
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating strategy
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating Strategy
EL 100.96 metres and rising. Three sluice
gates are currently open and water is being
released into Wivenhoe Dam.
Releases are currently 468 m3/s.
(excluding Somerset Dam outflows) is
5500 m3/s based on rainfall observed on the
ground. The Wivenhoe Dam lake level should
approach EL 71 under the current strategy.
Page: 3 of 5
Impacts
Bridges
o Twin Bridges
o Fernvale Bridge
o Savages Crossing
o Burtons Bridge
o Kholo Bridge
o Mt Crosby Bridge
o Colleges Crossing
Other streams
o Lockyer Creek
o Bremer River
flows
Tides
may be closed tomorrow due to flows into the
catchments below the dam. Whether these
bridges close will depend on rainfall over the
next 12 hours, particularly in the Lockyer
catchment.
State agencies
Strategies
catchment averages of 35mm above Wivenhoe
Dam and 100mm below Wivenhoe Dam until
the system clears the catchment areas. The
rainfall system appears to be moving
southwards and is forecast to substantially
clear the dam catchment areas by Tuesday.
Leslie Harrison Dam
Situation
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating strategy
commenced through all four gates. Releases
are expected to continue throughout today,
and may increase further depending on rainfall.
Page: 4 of 5
Page: 5 of 5
Date
28 January 2013
Time
06:00
Duty
Engineer
Page: 1 of 5
North Pine Dam
Current Strategy
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
A Flood Event was declared at 16:00 on the
Sunday 27th January in accordance with the
provisions of the Manual.
The flood is
classified as large under the Manual, with dam
inflows reaching 1350m3/s.
EL 39.72 metres and falling slowly. Current
releases are approximately 620m3/s. The dam
peaked at 23:00 hours on the 27th of January.
Releases to drain the dam back to full supply
will continue for the rest of the day, provided
that no further significant rainfall occurs.
Impacts
Bridges
o A. J. Wylie
Other streams
Sidling Creek Dam is currently releasing flood
inflows through the spillway. Peak inflow into
Sidling Creek Dam is estimated to be
approximately 180m3/s with a flood volume of
8,000ML.
State agencies
Young’s Crossing.
Rain outlook
Strategies
Page: 2 of 5
Overall Strategy
Cyclone Oswald. No change has been made to
the Somerset Dam Full Supply level.
A Flood Event was declared at 12:00 on
Sunday the 27th of January in accordance with
the provisions of Section 8 of the Manual. A
transition strategy to move from dam lowering
operations to flood operations was approved
by DEWS.
from Wivenhoe Dam are being decreased to
Brisbane.
Once the peaks have passed,
be drained.
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating strategy
Somerset Dam is being operated under
Strategy S2.
EL 101.45 metres and rising. The peak inflow
into the dam was approximately 3,500m3/s on
Sunday afternoon. The total inflow volume to
4:00am on Monday the 28th of January is
212,000ML. Inflows will continue over the next
Three sluice gates are currently open and
discharging approximately 570m3/s into
Wivenhoe Dam.
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating Strategy
Releases are currently 113m3/s and are being
reduced further over the next 2 hours. The
peak outflow from the dam to date was
1,230m3/s during Sunday afternoon.
Releases will be increased to drain the dam
after the flood peaks for Lockyer Creek and the
Bremer River have passed.
The estimated peak inflow into Wivenhoe Dam
(excluding Somerset Dam outflows) is
approximately 5,600m3/s based on the
recorded rainfall across the catchment.
The Wivenhoe Dam lake level is estimated to
reach EL 70 under the current strategy.
Page: 3 of 5
Impacts
Bridges
o Twin Bridges
o Fernvale Bridge
o Savages Crossing
o Burtons Bridge
o Kholo Bridge
o Mt Crosby Bridge
o Colleges Crossing
Other streams
o Lockyer Creek
o Bremer River
flows
Tides
may be closed later today due to flows into the
catchments below the dam.
Whether these bridges close will depend on
flows over the next 12 hours, particularly in the
Lockyer catchment.
The adopted gate strategy has been provided
to the Bureau of Meteorology.
State agencies
Strategies
catchment averages of between 10 and 20mm
are possible above Wivenhoe Dam and 20 to
30mm below Wivenhoe Dam until the system
clears the catchment areas. The rainfall
system is moving southwards and is forecast
to clear the dam catchment areas by Tuesday.
Leslie Harrison Dam
Situation
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating strategy
Seqwater are currently releasing 29m3/s from
Leslie Harrison Dam.
The total flood volume for Leslie Harrison Dam
to date is approximately 5,500ML with
approximately 1,900m3/s being released to
date.
Releases are expected to continue throughout
today, and may increase depending on rainfall.
Page: 4 of 5
Page: 5 of 5
Date
28 January 2013
Time
19:00
Duty
Engineer
• Releases are occurring from Somerset Dam.
• Releases are occurring from Leslie Harrison Dam.
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Page: 1 of 5
North Pine Dam
Current Strategy
• Dam levels
(current and peak)
• Dam volumes
• Gate status
• Inflows
• Releases
(current and peak)
provisions of the Manual. The flood is
inflows reaching approximately 1500m3/s.
Maximum release from the dam to date is
800m3/s. The dam peaked at approximately EL
39.80m at 21:00 hours on the 27th of January.
releases are approximately 600m3/s.
will continue overnight. At this stage it is
expected that releases will be shut down in the
morning to allow traffic over Young’s Crossing,
however this will be reassessed in the
morning. It is likely that releases will need to
recommence the following night to return the
storage to FSL.
Impacts
• Bridges
o A. J. Wylie
• Other streams
Young’s Crossing will remain closed overnight.
At this stage it is expected that releases will be
shut down in the morning to allow traffic over
Young’s Crossing, however this will be
reassessed in the morning.
Sidling Creek Dam level is falling and releasing
flood inflows through the spillway. Releases
are decreasing and, barring further rain, are
expected to be low enough to allow Young’s
Crossing to open tomorrow.
State agencies
Young’s Crossing.
• Rain outlook
• Strategies
The BOM have advised that there is unlikely to
be further significant rain. The overall strategy
is to return the dam to FSL while minimising
downstream disruption caused by the releases.
Page: 2 of 5
Overall Strategy
by DEWS.
Strategy S2, and Wivenhoe Dam under
Strategy W2.
• Dam levels
(current and peak)
• Dam volumes
• Gate status
• Inflows
• Releases
(current and peak)
EL 101.60 metres and steady. The peak inflow
Sunday afternoon.
Wivenhoe Dam.
• Dam levels
(current and peak)
• Dam volumes
• Gate status
• Inflows
• Releases
(current and peak)
at 4:00pm on 25/1/13 and are continuing. All
gates are currently closed. The peak inflow into
the dam was approximately 6,000m3/s
(excluding Somerset Dam outflows) on
Monday morning. The peak outflow from the
dam to date was approximately 1,200m3/s
during Sunday afternoon.
All gates at Wivenhoe Dam have been shut to
be drained.
Releases from the dams will likely continue for
about a week to return the dams to their FSLs.
reach approximately EL 71.5m on Tuesday
night under the current strategy.
Page: 3 of 5
Impacts
• Bridges
o Twin Bridges
o Fernvale Bridge
o Savages Crossing
o Burtons Bridge
o Kholo Bridge
o Mt Crosby Bridge
o Colleges Crossing
• Other streams
o Lockyer Creek
o Bremer River
• Threshold for damaging
flows
• Tides
Crossing, Burtons Bridge and Kholo Bridge are
closed. Mt Crosby Weir Bridge and Fernvale
Bridge may be closed overnight due to flows
into the Brisbane River from Lockyer Creek
and the catchments below the dam.
Once the peaks from Lockyer Creek and other
catchments below the dam have passed,
be drained. Releases from Wivenhoe will likely
mean that Twin Bridges, Savages Crossing,
Colleges Crossing, Burtons Bridge and Kholo
Bridge will be closed for the next week. At this
stage it is thought that releases will be able to
targeted to keep Mt Crosby Weir Bridge and
Fernvale Bridge open, once downstream
catchment flows reduce sufficiently to allow
these bridges to be opened.
State agencies
• Strategies
be further significant rain.
The overall strategy is to keep Wivenhoe Dam
shut to allow flood peaks emanating from
Lockyer Creek and the Bremer River to pass
through Brisbane. Once the peaks have
passed, releases from Wivenhoe Dam will be
increased to allow the flood waters stored in
the dams to be drained. Releases from the
dams will likely continue for about a week to
return the dams to their FSLs.
Leslie Harrison Dam
Situation
• Dam levels
(current and peak)
• Dam volumes
• Gate status
• Inflows
• Releases
(current and peak)
Current releases from Leslie Harrison Dam are
approximately 30m3/s.
The current dam level is approximately EL
18.30m.
today and tomorrow.
Page: 4 of 5
Page: 5 of 5
SITUATION REPORT NO 10a
Date
28 January 2013
Time
21:30
Duty
Engineer
This report rescinds and replaces Situation Report 10 issued at 19.00
Gates are currently closed at Wivenhoe Dam.
Monday the 28th of January 2013
to
3pm TUESDAY: 10 - 20 mm.
to
Page: 1 of 6
North Pine Dam
Current Strategy
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
provisions of the Manual. The flood is
Maximum release from the dam to date is
800m3/s. The dam peaked at approximately EL
39.80m at 21:00 hours on the 27th of January.
releases are approximately 600m3/s.
will continue overnight. At this stage it is
expected that releases will be shut down in the
morning to allow traffic over Young’s Crossing,
however this will be reassessed in the
morning. It is likely that releases will need to
recommence the following night to return the
storage to FSL.
Impacts
Bridges
o A. J. Wylie
Other streams
Young’s Crossing will remain closed overnight.
At this stage it is expected that releases will be
shut down in the morning to allow traffic over
Young’s Crossing, however this will be
reassessed in the morning.
Sidling Creek Dam level is falling and releasing
flood inflows through the spillway. Releases
are decreasing and, barring further rain, are
expected to be low enough to allow Young’s
Crossing to open tomorrow.
State agencies
Young’s Crossing.
Rain outlook
Strategies
Page: 2 of 6
Overall Strategy
by DEWS.
Strategy W2.
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating strategy
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating Strategy
EL 101.52 metres and steady. The peak inflow
Sunday afternoon.
Wivenhoe Dam.
and rising slowly. Releases from the dam
commenced for this event at 4:00pm on
25/1/13. Presently all gates are closed (no
flood releases occurring) pending the passing
of Lockyer Creek and Bremer River flood
peaks into the Brisbane River.
The peak inflow into the dam was
approximately 6,000m3/s (excluding Somerset
Dam outflows) on Monday morning. The peak
outflow from the dam to date was
approximately 1,200m3/s during Sunday
afternoon.
All gates at Wivenhoe Dam are currently shut
with no flood releases, allowing for the flood
peaks emanating from Lockyer Creek and the
Bremer River to pass into the Brisbane River.
Once the peaks have passed, releases from
Wivenhoe Dam will be increased to allow the
flood waters stored in the dams to be drained.
When they recommence, releases from the
reach approximately EL 71.5m on Tuesday
Page: 3 of 6
night under the current strategy.
Impacts
Bridges
o Twin Bridges
o Fernvale Bridge
o Savages Crossing
o Burtons Bridge
o Kholo Bridge
o Mt Crosby Bridge
o Colleges Crossing
Other streams
o Lockyer Creek
o Bremer River
flows
Tides
Crossing, Burtons Bridge and Kholo Bridge are
closed. Mt Crosby Weir Bridge and Fernvale
Bridge may be closed overnight due to flows
into the Brisbane River from Lockyer Creek
and the catchments below the dam.
Once the peaks from Lockyer Creek and other
catchments below the dam have passed,
be drained. Releases from Wivenhoe will likely
Bridge will be closed for the next week. At this
stage it is thought that releases will be able to
targeted to keep Mt Crosby Weir Bridge and
Fernvale Bridge open, once downstream
catchment flows reduce sufficiently to allow
these bridges to be opened.
State agencies
Strategies
The overall strategy is to keep Wivenhoe Dam
shut to allow flood peaks emanating from
Lockyer Creek and the Bremer River to pass
into the Brisbane River. Once the peaks have
passed, releases from Wivenhoe Dam will be
increased to allow the flood waters stored in
Leslie Harrison Dam
Situation
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating strategy
18.30m.
today and tomorrow.
Page: 4 of 6
Page: 5 of 6
Page: 6 of 6
Date
29 January 2013
Time
07:00
Duty
Engineer
Gates are closed at Wivenhoe Dam (since 6:00am yesterday).
Gates are closed at North Pine Dam (since 5:30am today).
Monday the 28th of January 2013
to
to
Page: 1 of 5
North Pine Dam
Current Strategy
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Cyclone Oswald.
provisions of the Manual. The flood was
Maximum release from the dam to date was
approximately 800m3/s. The dam peaked at
EL 39.80m at 21:00 hours on the 27 January.
EL 38.8 metres and steady and gates are
currently closed.
Releases have been temporarily ceased to
allow for opening of Young’s Crossing during
the day. Releases will recommence tonight if it
is necessary to return the lake level to the
Temporary FSL of EL 38.4 metres.
Impacts
Bridges
o A. J. Wylie
Other streams
Gate releases from North Pine dam ceased at
5:30am this morning to allow Young’s Crossing
to be reopened today. If additional releases
are required from North Pine Dam tonight,
Young’s Crossing will be closed this evening
and night.
Sidling Creek Dam lake level has continued to
fall, with only small flows passing through the
spillway. These levels will continue to drop
today.
State agencies
Regional Council regarding the reopening and
subsequent re-closure of Young’s Crossing
tonight.
Rain outlook
Strategies
Page: 2 of 5
Overall Strategy
Sunday 27 January in accordance with the
provisions of Section 8 of the Manual. A
by DEWS.
Strategy W2.
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating strategy
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating Strategy
EL 101.34 metres and falling slowly. The peak
inflow into the dam was approximately
2,800m3/s on Sunday afternoon.
Wivenhoe Dam.
and rising slowly.
afternoon.
The gates at Wivenhoe Dam were closed at
6:00am yesterday and currently remain closed.
This approach allows the flood peaks
emanating from Lockyer Creek and the Bremer
River to pass into the Brisbane River. Once
these peaks have passed Brisbane City,
releases from Wivenhoe Dam will recommence
to allow the now substantial volume of flood
water stored in the dams to be drained in a
controlled manner that minimises flood
impacts.
When releases recommence, it will take
approximately seven days to drain the stored
floodwater and return the dams to their Full
Supply Levels.
Page: 3 of 5
Impacts
Bridges
o Twin Bridges
o Fernvale Bridge
o Savages Crossing
o Burtons Bridge
o Kholo Bridge
o Mt Crosby Bridge
o Colleges Crossing
Other streams
o Lockyer Creek
o Bremer River
flows
Tides
Fernvale, Mt Crosby, Twin Bridges, Savages
Crossing, Colleges Crossing, Burtons Bridge
and Kholo Bridge are closed.
Recommencement of releases from Wivenhoe
Dam will be timed to allow for prompt
reopening of the Brisbane Valley Highway
(Fernvale Bridge).
The drain down releases from Wivenhoe Dam,
combined with downstream inflows, will likely
Bridge will be closed for the next seven days.
Releases from the dam over this period will be
made so that Mt Crosby Weir Bridge and the
Brisbane Valley Highway (Fernvale Bridge)
remain open.
State agencies
to the Bureau of Meteorology (BOM).
Strategies
be further significant rain over the next seven
days.
Once the flood peaks emanating from Lockyer
Creek and the Bremer River pass Brisbane
City, releases from Wivenhoe Dam will
recommence to allow the flood waters stored in
dams will likely continue for about seven days.
Leslie Harrison Dam
Situation
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating strategy
18.05m.
at least today.
Page: 4 of 5
Page: 5 of 5
Date
29 January 2013
Time
18:00
Duty
Engineer
Gates are open at Wivenhoe Dam (since 12:00pm today).
Gates are closed at North Pine Dam (since 5:30am today).
Gates are closed at Leslie Harrison Dam (since 4:00pm today).
Tuesday the 29th of January 2013
to 4pm WEDNESDAY: 5mm.
to 4pm WEDNESDAY: 5mm.
Page: 1 of 6
North Pine Dam
Current Strategy
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
A Temporary Full Supply Level of 38.4m
previously declared for North Pine Dam was
revoked today by notification published in the
Queensland Government Gazette.
provisions of the Manual. The flood was
Maximum release from the dam to date was
approximately 800m3/s. The dam peaked at
EL 39.80m at 21:00 hours on the 27 January.
The North Pine Dam lake level was lowered to
EL 38.8 metres this morning and gates were
closed.
With the revocation of the temporary full supply
level declaration no further releases are
planned from North Pine Dam.
Impacts
Bridges
o A. J. Wylie
Other streams
State agencies
No gate releases have occurred at North Pine
Dam since the last Situation Report.
Rain outlook
Strategies
Moreton Bay Regional Council have been
advised that no further releases are planned.
Page: 2 of 6
Overall Strategy
Sunday 27 January in accordance with the
provisions of Section 8 of the Manual. A
by DEWS.
Strategy W2.
After gradual rises when Wivenhoe Dam gates
were closed, the Wivenhoe dam lake level is
starting to stabilise.
A change to drain down strategy is expected to
occur overnight.
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating strategy
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating Strategy
EL 101.34 metres and falling slowly. The peak
inflow into the dam was approximately
2,800m3/s on Sunday afternoon. The inflow as
at 1600 hrs today was approximately 270m3/s.
Wivenhoe Dam.
Wivenhoe Dam lake level at 1600hrs today
was EL 70.14m and rising very slowly. The
lake level is expected to peak at approximately
EL 70.30m around midnight tonight.
afternoon.
The flood flows from Lockyer Creek peaked at
approximately 00:00hrs this morning.
The gates at Wivenhoe Dam were opened at
1200hrs today after it was confirmed that
Brisbane Valley Highway bridge at Fernvale
was opened at 11:00hrs and clearly evident
that Lockyer Creek flood flows were receding.
Releases from Wivenhoe dam are being
increased gradually from approximately
Page: 3 of 6
125m3/s at 1200 hrs today to approximately
450m3/s at 1800 hrs.
Further gradual
increases in releases will occur overnight.
The releases rates are being targeted to:
keep Brisbane Valley Highway open
allow Mt Crosby Weir to be reopened:
ensure no increase in downstream
flows above peaks that have already
occurred, and
to meet the drain down requirements
of the Manual.
The river levels at Mt Crosby Weir have now
receded sufficiently to allow cleanup of the
Weir Crossing to commence. The Mt Crosby
Weir Crossing is not yet open for vehicle
access and is expected to open tomorrow
morning.
It will take approximately seven days to drain
the stored floodwater and return the dams to
their Full Supply Levels.
Impacts
Bridges
o Twin Bridges
o Fernvale Bridge
o Savages Crossing
o Burtons Bridge
o Kholo Bridge
o Mt Crosby Bridge
o Colleges Crossing
Other streams
o Lockyer Creek
o Bremer River
flows
Tides
State agencies
Mt Crosby Weir, Twin Bridges, Savages
Crossing, Colleges Crossing, Burtons Bridge
and Kholo Bridge are closed.
The drain down releases from Wivenhoe Dam,
combined with downstream inflows, will likely
Bridge will be closed for the next seven days.
Releases from Wivenhoe Dam will continue to
be set to allow the Brisbane Valley Highway
(Fernvale Bridge) to remain open and allow Mt
Crosby Weir to be reopened.
Strategies
be further significant rain over the next seven
days.
Releases from the dams will likely continue for
about seven days in accordance with drain
down requirements.
to the Bureau of Meteorology (BOM).
Page: 4 of 6
Leslie Harrison Dam
Situation
Dam levels
(current and peak)
Dam volumes
Gate status
Inflows
Releases
(current and peak)
Operating strategy
The gates at Leslie Harrison Dam were closed
at 1600 hrs today.
17.80m.
Page: 5 of 6

Report on the operation of North Pine Dam

Transcription

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