managing water resources under scarcity and climate change, gloria abouzeid and amal bushara, ifad-...
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Managing water resources under
scarcity and climate change
Theib OweisDirector, Integrated water and Land Management program, ICARDA, Aleppo, Syria
For IFAD-ICARDA knowledge and technology exchange in NENA region, October 2009
Dry areas, water scarcity & Climate change
Southern Mediterranean
ICARDA
• Water scarcityProjections alarming
• Climate changeDrier Extreme eventsDrought
• Less water for agricultureMore food needed
• ConsequencesSocial, economical, conflicts
Globally: Retain diversions to agriculture at the year 2000 levels
Dry areas: Managing with less water
Increasing Efficiency / productivity
Scarcity coping strategies
Drought management
W&Lproductivityimprovement
W&L resources assessment
Combating land degradation
Policies & institutions
NARS training
Integrated Water and Land ManagementProgram
ICARDA new strategy
• Increasing agricultural water productivity
• Risk management, drought & climate change
• Integrated land & water management
• Diversification
Approaches
• Partnership with NARS
• Community-based
• Participatory
• Integrated
• Benchmarking and scaling out
Storage
Irrigation
Precipitation
Real vs. paper water losses
Runoffrecoverable
Transpiration
EvaporationLosses
To ground waterrecoverable
Deep percolationDrainagePartially recoverableQuality losses
Seepagerecoverable
Irrigation efficiencies: not enough
Reflects irrigation performance
Ignore recoverable losses
Does not reflect productivity
Water productivity: the concept
ReturnWP = --------------------------------- Unit of water consumed
What return ?? Biomass, grain, meat, milk (kg) Income ($) Environmental benefits (C) Social benefits (employment) Energy (Cal) Nutrition (protein,
carbohydrates, fat)
What water ?? Quality (EC) Location (GW depth) Time available
Consumed (depleted) Evaporation Transpiration Quality deterioration
Scales and drivers to increase WP
At the basin level: competition among uses (Env., Ag.,
Dom.) conflicts between countries Equity issues
At the national level: food security hard currency sociopolitics
At the farm level: maximizing economic return Nutrition in subsistence farming
At the field level: maximizing biological output
Tradeoffs between water & land productivity
Max WP
Max Yield
Range of WPs
Potential WP improvements
Reducing evaporation Improving
management Enhancing genetic
resources Great potential in
developing countries
Dependence on green and blue water
August 2006
114
654
1080
239
787
1505
1692
907
219
Areas in green: agriculture mainly under rainfed
Areas in blue: agriculture mainly under irrigation
Circles depict total crop depletion
Why rainfed systems?
Soil moisture deficit/yields
0
1
2
3
4
Gra
in y
ield
(t/h
a)
Ow
eis
9 4
Average rainfed grain yield of wheat in some WANA countries
Dec. Jan. Feb. March April May
Wheat growing season
0
20
40
60
80
100
120
140
160
Crit
ical
moi
stur
e in
root
zon
e (m
m) Required Available
Typical soil-moisture pattern over a Mediterranean-type wheat growing season
Yield gaps in rainfed areas
• Rainfed yields globally
• Global yield gaps
• Yield gap in wheat in Syria 1994-2005
Constraints in rainfed areas
• Physical Constraints– Water scarcity– Loss of organic matter– Soil erosion– Nutrients depletion
• Socioeconomic constraints– Small holdings– Capacity for investment– Policies– Markets
Supplemental irrigation
Irrigating basically rainfed crops,normally produce without irrigation,to improve and stabilize production
Impact of supplemental irrigation on rainfed wheat in northern Syria
234 mm 316 mm 504 mm
Total annual rainfall (mm)
0
1
2
3
4
5
6
7
Gra
in y
ield
(t/h
a)
Rainfed SI
183mm
120mm
75mm
Outstanding opportunities in highlands
3.1
5.35.9
6.2
4.4
2
0.8 1
0
1
2
3
4
5
6
7
rainfed Sowing SI Deficit SI Full SI
Grain yield (t/ha) Water productivity (Kg/m3)
Turkey highlands /bread wheat
Rain usually late for good crop stand before winter frost dormant
SI for early germination Further gains in spring SI
0
5
10
15
20
25
30
35
40
45
50
21-Sep 26-Sep 01-Oct 06-Oct 11-Oct 16-Oct 21-Oct 26-Oct 31-Oct
Sowing period for wheat
Pro
bab
ilit
y o
f cu
mu
lati
ve r
ain
fall
in
% 30 mm rainfall40 mm rainfall50 mm rainfall
Advantage over full irrigation
Impact on wheat production in Syria
Contribution of inputs to rainfed yield increases
Badia: Rain is mostly lost
in evaporation in salt sinks
Water harvesting
WH System Components
• The catchment• The target• The storage facilities
Macrocatchments
Catchment
Target
Storage runoff
Cisterns
Small water harvesting reservoirs
Jessour - Tunisia
Micro-catchments
Small runoff basins (negarim)
Contour ridges
Runoff strips for field crops
Semicircular bunds
Mechanization
Water harvesting from greenhouses
Rooftop water harvesting
Roaded catchments
Contour bench terraces
Tunisia Yemen
Thank you
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