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MANAGING VARIABILITY OF WATER RESOURCES IN RIVER BASINS FOR ENHANCED FOOD AND LIVELIHOODS SECURITY

Smakhtin, V., Pavelic, P., McCartney, M., Amarnath, G., Eriyagama, N., Bharati, L., Cai, X.

 International Water Management Institute

Sri Lanka – Laos – Nepal –South Africa

GWSP Conference: Water in the Anthropocene. May 2013. Bonn, Germany

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TOO MUCH…TOO LITTLE…

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Variability increases with climate change

Source: Dartmouth Flood Observatory

Variability increases water scarcity

Variability has important positive implications

Variability determines flood risk and damages

FACETS OF WATER RESOURCES VARIABILITY

RRR

IrrigationRainfed

Basins

RRR

IrrigationRainfed

Information

Nile

Volta, Niger

Andes

Zambezi, Limpopo

Mekong

Ganges

Indus

Amu DaryaSyr Darya

Tigris, Euphrates

VARIABILITY MANAGEMENT AS A FOCAL RESEARCH AREA OF THE WLE PROGRAM

Research Areas:

• Variability Management• Resource Allocation and Benefit Sharing • Water-Energy-Food nexus in Basins• Water Accounting

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RESEARCH DIRECTIONS

• Technical and economic design and appraisal of diverse water storage “portfolios”

• Quantifying and considering ecosystem services of natural storage “infrastructure” in basin development

• Detailed characterization and mapping of flood and drought risks and hot spots

• Exploring underground solutions for conjunctive management of floods and droughts in a same basin

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WATER STORAGE CONTINUUM

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EVALUATING STORAGE OPTIONS

Storage – Drought Deficit Index (how much of the long-term annual hydrological drought deficit is satisfied by

the existing large storage capacity in a county) Livestock storage need (based on livestock density per cell, poverty levels, water availability, etc)

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EVALUATING REGULATING ROLE OF NATURAL STORAGE (example - wetlands in Zambezi basin)

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AGRICULTURE; PAGE (2005)

POPULATIONCIESIN - 2010

FLOOD EXPOSED GDPWB, 2010

• Globally - 90 grid cells of 100 km with catastrophic flood occurrence > 5, during 1900-2010

• Damage analysis

ANALYSING FLOOD HOT SPOTS AND FLOOD MAPPING

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ANALYSING FLOODING HOT SPOTS AND FLOOD MAPPING

Ganges Basin

ANALYSING FLOODING HOT SPOTS AND FLOOD MAPPING

Flooded area (2000 – 2011)

2010

2010

8-days maps of inundation extent

Annual maps of maximum inundation

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CONJUNCTIVE FLOOD AND DROUGHT MANAGEMENT

Current Situation – Dry Season

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CONJUNCTIVE FLOOD AND DROUGHT MANAGEMENT

Current Situation – Wet Season

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CONJUNCTIVE FLOOD AND DROUGHT MANAGEMENT

Underground Taming of Floods for Irrigation (UTF-I);

Wet season

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CONJUNCTIVE FLOOD AND DROUGHT MANAGEMENT

Underground Taming of Floods for Irrigation (UTF-I);

Dry season

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CONJUNCTIVE FLOOD AND DROUGHT MANAGEMENTUTF-I in plan view

CONJUNCTIVE FLOOD AND DROUGHT MANAGEMENT UTF-I desktop case study: Chao Phraya basin, Thailand

Source: DFO

Land Use Regular Flooding Alluvium aquifers

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CONJUNCTIVE FLOOD AND DROUGHT MANAGEMENTUTF-I desktop case study: Chao Phraya basin, Thailand

• Harvest water only exceptionally wet years. 25% of the MAR is harvestable

• 100 km2 dedicated land to flood harvesting needed (< 1% of the Basin area)

• Additional 270,000 ha of irrigation possible

• $150 mill / year - income to smallholder farmers

• Cost < $ 1 Bill. Payback time – under 7 years

• No analogs so far exist

• Scaling up this solution to SA and SEA; needs:– Detailed design (should be as clear as the current design of surface reservoirs)– Identification of areas in a larger region that are suitable for piloting (flood hot spots,

hydrogeology, etc)– Several pilot experiments

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CONCLUSIONS

• Water resources Variability is a primary issue in basin water resources planning and management globally

• Management of temporal Variability should consider a variety of storage options and their combinations, large and small, man-made and natural ones

• Understanding and characterization of Variability hot spots may help target related research and investments

• Subsurface solutions for water resources Variability management may have significant potential for flood and drought mitigation, increasing irrigation water availability and improving livelihoods. This potential is still to be realized

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