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