ccafs science meeting item 05 vladimir smakhtin - water storage

VLADIMIR SMAKHTIN

International Water Management Institute,

Colombo, Sri Lanka

WATER STORAGE FOR CLIMATE RISK

MANAGEMENT

Third Annual CCAFS Science Workshop

Copenhagen, Denmark, 1 May 2012

Water for a food-secure world

WATER SCARCITY AND CLIMATE CHANGE

1/3 of the world’s population live in basins that have to deal with water scarcity

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MANAGING VARIABILITY

• Climate Change impacts, in the water sector, manifest themselves

through increasing variability

• The best way to adapt for Tomorrow is to improve our ability to deal

with water resources variability - Today

• Managing Variability in river basins is largely about storing as much

water as possible, in as environmentally and socially acceptable

way as possible

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WATER STORAGE CONTINUUM

Water for a food-secure world Water for a food-secure world

RE-THINKING LARGE STORAGE

Ethiopia GDP vs Rain Storage per capita

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RE-THINKING LARGE STORAGE

Dams can be constructed and operated in ways that

optimize benefits for all, including riparian

communities and environment

• Incorporate livelihoods’ options into large reservoir

planning and operation

• Quantify and implement the required environmental

releases

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EVALUATING STORAGE OPTIONS

Basin scale analyses Evaluation of climate change impacts on storage at basin scale (Hydro and WR Models)

Site level analyses Understanding storage at the local (economic, socio-political aspects)

Evaluation metrics to assist in planning and management of storage

Water for a food-secure world

MAPPING THE NEED FOR STORAGE

Based on Poor rural population density,

Livestock density, amount of rainfall,

variability of rainfall

Livestock storage need

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FOCUSING ON GROUNDWATER

Water for a food-secure world

GROUNDWATER AS ADAPTATION OPTION –India

India

USA

W. Europe

China

VN, SL

Bang., Pak

Groundwater use in Asia

District-wise stage of GW development (%)

Source: CGWB, 2004

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GROUNDWATER AS ADAPTATION OPTION –India

Managed Aquifer Recharge vs other storage options

Measurable criteria Small

Surface

Storage

Large

Dams

Managed

Aquifers

Water where needed 3 2 5

Water when needed 1 2 5

Level of water control 1 2 5

Non-beneficial losses –e.g.

evaporation -4 -2 -1

Protection against a single

annual drought 1 2 5

Protection against

successive droughts -1 1 4

Ease of recovery during

monsoon 5 4 3

Other

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STORING FLOODS

Current Situation – Dry Season

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STORING FLOODS

Current Situation – Wet Season

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STORING FLOODS

Possible Future – Wet Season

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STORING FLOODS

Subsurface Solution

Water for a food-secure world

Harvest Floods Do Not Harvest

STORING FLOODS

Chao Phraya River Basin, Thailand

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STORING FLOODS

Chao Phraya River Basin, Thailand

• 5700 MCM/year - harvestable – around 15% of mean annual river

flow

• About 200 km2 dedicated area to Managed Aquifer Recharge

• Additional 270,000 ha can be irrigated

• $200 M+ /year income to smallholder farmers

• No precedents so far: detailed technical and institutional studies

needed

• Analyze this: if only 15% of India total flow is harvested similarly, it

could increase its national water supply by 285 km3 – half of India’s

total current water withdrawal

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THANK YOU

• Paul Pavelic (IWMI, India)

• Lisa-Maria Rebelo (IWMI-Laos)

• Matthew McCartney (IWMI-Ethiopia)

• Tushaar Shah (IWMI, India)

• Aditi Mukherji (IWMI, India)

• Nishadi Eriyagama (IWMI, Sri Lanka)

• Prathapar Sanmugam (IWMI, India)

IWMI CLIMATE CHANGE WEB SITE :

www.iwmi.cgiar.org/Topics/Climate_Change/default.aspx