Global debate on irrigation water use

INCREASING or REDUCING IRRIGATION WATER
Global debate on irrigation water use
Increasing by 15-20% for food security
or
R d i b
Reducing
by 10% ffor eco-environment
i
t
What to do ?
Global issues on the water saving in rice paddy
WWF-2 focused on irrigation efficiency for food production:
Through improving irrigation efficiency !
Saving irrigation water and diverting to drinking, ecosystem water !
Conserving water than developing as pressure on environment !
WWF-3 focused on multi-function of paddy irrigation :
Possible to increase food production without increasing irrigation water ?
Multi-function of paddy farming should be preserved for culture and ecology.
H to
How
t reduce
d
the
th water
t use while
hil preserving
i the
th currentt eco-system
t ?
WWF-4 focused on integrated water resources management :
Still irrigation water is most responsible for the over-consuming water.
Integrated water resources management was recommended.
O & M cost should be covered by private sector than by public sector
1
Foundation of INWEPF and PAWEES
Irrigated rice farming in the paddy has been developed in the Asian monsoon
region not only to provide stable food security, but also to maintain the multifunctionality such as culture, ecology, and environment in the rural society.
But, the social effects of irrigated paddy and the economic values of
multifunctionality are not clearly defined,
defined because of a lack of reliable data
and suitable evaluation techniques. After having the multifunctionality session
in WWF-3 in Kyoto 2003, the INWEPF and PAWEES were officially founded.
The purpose of PAWEES is to study
multi functionality
multi-functionality
of
irrigated
paddy fields in acadedmic way and
propagate its importance to the
Western countries where cultivating
dry crops and not being familiar with
rice farming. PAWEES has annual
conference and publishes quarterly
academic jounal PWE.
The purpose of INWEPF is to study the
food security and poverty alleviation,
alleviation
sustainable water use and share the
partnership. Its activities affect the
decision makers of national policy to
allot a proper amount of budget for
agriculture and reflect the facts to the
world trade negotiation of agricultural
products.
6th PAWEES Conference and Agenda meeting
Agenda 1 :
Engineering Accreditation system
for Agricultural Engg. Education in
paddy farming regions.
Agenda 2 :
Establishment of new agricultural
engineering category in the APEC
engineering system.
Agenda 3 :
Upgrading the PWE (Paddy and
Water Environment) journal.
Agenda 4 :
Textbook for Agricultural Engineer
Ethics and Ecological Engineering
in Paddy farming.
2
Connect
Connect,
http://pawees/net/
Contact,
Tai Cheol, Kim (2011-2012)
6th INWEPF Steering meeting and symposium
• Date:16-18 November 2009
• Venue: JICA Research Institute, Tokyo
• Participant:16 member countries,
2 int’l organization with 100 person
Steering meeting
WG1: multiple role of paddy fields
(by Malaysia)
WG2: Vision, policy and informatio
n dissemination (by Korea)
WG3: Contribution to technical coo
peration (by Japan)
3
Bangladesh, Cambodia, China, India, Indonesia, Japan, Korea, Laos, Malaysia,
Myanmar, Nepal, Pakistan, Philippines, Sri Lanka, Taiwan, Thailand, Vietnam
Report in the WG-CROP, ICID
Saving irrigation water and/or
C
Conserving
i eco-system in
i rice
i paddy
dd
2011 Oct. 18
Tai Cheol, Kim
Professor, Chungnam National University, Korea
4
WATER BALANCE IN THE PADDY
Watershed area : 376 sq. km
Benefit area : 8,788 ha
Storage capacity : 47MCM
to investigate how much water is applied, wasted, and can be saved.
In the district of Yedang reservoir for 30yrs (Kim, 2004)
Run
off
Amount of irrigation
water (8,788ha)
Rain
fall
Inflow
Unit
㎜
103 ㎥
%
103 ㎥
㎜
%
1966
1,289
254,000
52.8
83,508
950
1967
952
182,452
51.3
71,105
810
1968
917
186,030
54.3
69,152
1969
1,740
506,851
78.0
1970
1,285
318,436
66.4
Year
ratio
Percola
-tion
Net
duty
of
water
(㎜)
Water
applied
(㎜)
492
540
1,475
492
744
1,198
576
492
680
1,175
536
591
492
547
2,311
854
691
525
492
326
1,636
Rain
in irri.
season
(㎜)
Eff.
rain
fall
(㎜)
ET
(㎜)
181
763
525
573
154
548
388
640
787
150
492
388
155,998
1,775
339
950
83,037
945
180
(㎜)
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
1991
1,224
.
.
277,523
60.7
95,217
1,083
207
862
488
595
492
599
1,571
1992
1,111
217,511
52.4
67,042
764
146
677
375
625
492
742
1,139
1993
1,094
243,908
69.7
69,315
789
150
729
455
579
492
616
1,244
1994
1,191
225,474
50.7
105,438
1,528
229
712
346
707
492
853
1,874
1995
1,383
388,096
75.2
107,966
1,565
234
1,173
226
633
492
899
1,794
Mean
1,180
258,586
57.6
80,203
935
174
761
448
597
492
641
1,383
5
Average annual water balance in the paddy field
Evapo-transpiration
659㎜
Precipitation
946㎜
(Eff.581)
Irrigation
1,565㎜
Surface runoff
365㎜
Percolation
1,487mm
Return flow
995㎜
Deep Percolation
492㎜
?
Target to save or
conserve
Intake
ET
Rain
1,565mm
946
659
R
i
Total amount of water = 2,146 (100%)
v
Eff. rainfall (581) = Rainfall(946) – Flood flow(365)
e
Total amount of water 2,146 = 1,565 + 581
r
Cropping & facilities
995
Return flow
995 (46%)
Percolation
492
Flood flow
365
Ground
water
Target to save : Managing water of 995mm for cropping and facilities circulated as
returned flow is blamed as wasted water, but it is functioning to improve the ecosystem services.
6
Inlet of irrigation canal
Outlet of drainage canal
Waste of water or sound circulation for eco-system?
Managing water of 995mm is circulating the paddy fields
continuously and functioning to purify water quality, conserve
ecosystem, and recharge groundwater in watershed scale.
7
Waste of water or Sound circulation for eco-system (100mil㎥)
Safe
freq.
Area
Evapo-
10,000 transpirat
Perco-
water
Eff.
Net water
Facility
Supplied by
lation
in plot
rainfall
required
managing
facility
Total
irrigation
water
water
ha
ion
10 yr
42.1
23.8
20.7
44.5
16.1
28.4
37.6
66.0
82.1
32.9
49.2
7 yr
6.2
4.2
3.1
7.3
2.4
4.9
2.7
7.6
10.0
4.0
6.0
5 yr
5.0
3.1
2.5
5.6
2.9
2.7
3.1
5.8
8.7
3.4
5.2
3 yr
12.2
6.8
6.0
12.8
6.1
6.7
5.4
12.1
18.2
7.3
10.9
2 yr
22.5
12.9
11.1
24.0
11.8
12.2
6.6
18.8
30.6
12.2
18.4
Total
88
50.8
43.4
94.2
39.3
54.9
55.4
110.3
149.6
59.8
89.7
Non-irrigated
g
26.9
17.7
13.2
30.9
15.6
15.3
-
((15.3))*
30.9
12.4
18.5
Sub-total
114.9
68.5
56.6
125.1
55
70.2
35.4
110
180
72
108
Irrigated upland
9.2
5
5
Non-irrigated
83.8
Sub-total
93
35
5
40
Total
207.9
90
115
220
72
148
Irrigated
5
35
water use
Broad
Return
required
ALTERNTIVES for WATER SAVING or MULTIFUNCTION
In the case 1, it is currently to supply water with ET of 659mm, percolation of
492mm, and management of 995mm which has a function of return flow and
conserve the present sound eco-system.
(more water, more rice & eco-system and to avoid the damage of repeated
cultivation))
In the case 2, it is enough to supply water with ET and percolation of 492mm
essential to rice paddy farming. But, there is no return flow and so no water is
available to conserve the present sound eco-system.
(less water, poor rice taste & poor eco-system)
In the case 3 of most extreme, it is enough to supply water only with ET of
y consumed by
y the rice pplant. In this case,, sprinkler
p
659mm which is actually
irrigation is available for upland rice and/or dry crops.
(less water, less rice and poor taste & eco-system)
In case of 4, to find out the amount of target to save ranging from max. 995mm
to a certain optimal amount.
(less water, more rice & eco-system and to avoid the damage of repeated
cultivation)
8
Case 1 Case 2
Case 3 Case 4
We are afraid paddy is converted into upland & the eco-system is totally changed.
Wisdom based on “Land & Water” (JIID, 2003)
After WTO, cultivated paddy has been reduced by half in Taiwan, drastic change of the eco-system such
as loss of scenery & landscape and groundwater level & land subsidence.
1,600 species of insect inhabit a paddy field
near the Omiya suburbs in Japan.
Wisdom based on “Land & Water” (JIID, 2002)
1,600 species of insect inhabited in paddy field
100 or more species of insect inhabited in dry field
near the Omiya suburbs in Japan.
near the Omiya suburbs in Japan
9
Response on the water balance from agricultural sector
It is true that continuous flooding irrigation in paddy
fields consumes lot of water much more than it needs.
But, it is also true that only irrigation techniques that
farmers have adapted to the local conditions through a
long process of trial and error in the history have been
succeeded to the descendants.
Supplied water is not wasted, but circulate and reuse
repeatedl It contrib
repeatedly.
contributes
tes a lot to conser
conservee eco
eco-system
s stem
services in the watershed.
Consequently, farmers are maintaining the continuous
flooding irrigation adapted to environments in the history.
Values of the eco-system services in paddy
The 21st century is called “Water century” or “Century of
ecology”. Paddy irrigation have multiple roles not only
food production,
production but also flood control,
control ground recharge,
recharge
soil erosion mitigation, landscape, air & water
purification, and regional water supply such as fire
fighting or waterway.
Furthermore, paddy irrigation has played a significant
role for sound hydrological cycle and wide range of
amenities related to community, culture and environment.
Water for eco-system services increase its importance in
water management related to tackling climate change,
conserving biodiversity and other issues.
10
Improving the eco-system services
Natural environment and rural culture in Asian monsoon
region are closely related to paddy irrigation agriculture.
Seasonal irrigation
g
practices not only
p
y determine the
hydrologic regime, but also form the aquatic environment
affluent in biodiversity, the beautiful landscape in seasons,
and the history and culture of the society in the watershed.
Especially under the recent changes of the situations, i.e.
urbanization
b i ti
b rapid
by
id economic
i growth,
th and
d increase
i
off
extreme drought and flood risks by the climate change, it
is important for all the stake holders including farmers to
make necessary actions for enhancing the environment, the
eco-system services, and the traditional cultures.
Table Valuation on Multi-functionality of Paddy Farming in Korea
: physical and conservation functions only (unit: 100 million KRW)
Items of multifunctionality
Eom
(1993)
RDA
(1994)
Oh
(1995)
Yoon
(1996)
KREI
(2001)
Park
(2003)
Flood control
15,824
16,000
8,655
-
13,305
14,057
g
Water storage
-
-
9,839
,
10,073
,
11,427
,
23,857
,
Improving water quality
59,615
59,611
12,325
-
11,946
3,887
Soil erosion control
667~
2,061
2,173
-
19,047
4,532
1,648
Waste disposal
-
-
391
-
882
-
p
p
purification
Atmosphere
27,979~
56 869
56,869
56,773
,
46,246
,
3,076
,
22,118
,
113,705
,
Reducing temperature
-
2,208
-
-
-
2,062
Keeping nature scenery
-
3,000
-
-
-
-
Total (billion US$)
10.4~13.4
14.0
7.8
3.2
6.4
15.9
11
How much and how to save irrigation water?
The issue to debate is how much water could be reduced
out of managing water without reducing yield and how
much agricultural water can be saved while conserving
the sound eco-system
eco system services and rural amenity?
Paddy field irrigation has the “Multifunctional roles" of
recharging groundwater, mitigating floods, providing a domestic
water supply and water for fish farming, passing on traditional
culture, protecting biodiversity, forming aquatic landscapes,
environmental services and other socio-economic effects.
Since paddies consume only some of the water withdrawn, it is
important to improve recycling so that seepage from paddies can
be reused downstream.
Deliberate research and discussion should be carried out.
SUMMARY and RECOMMENDATION
1) Irrigation in paddy field has the “Multifunctional roles" of recharging
groundwater, mitigating floods, providing domestic water supply, water for fish
farming passing on traditional culture,
farming,
culture protecting biodiversity
biodiversity, forming aquatic
landscapes, environmental services, and other socio-economic effects.
2) Vitalizing the Rural Improvement Act to keep the agricultural water right and
to develop the rural water for more amenity.
3) What is the optimal amount of irrigation water for saving and rural water for
conservation of eco-system?
4) Practical strategy and incentives system for farmers voluntarily to save water.
5) Conserving the eco-system by the irrigation networks to boost up green tourism.
6) How much irrigation water in rice paddy can be saved
while conserving/improving the eco-system services should be investigated.
12
CONSERVING ECO-SYSTEM
Agriculture +
Water
?
+ Eco-system = Amenity
Prof. Kim’s equation
13