Post on 25-May-2015
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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
Water for a food-secure world Water for a food-secure world
WATER STORAGE CONTINUUM
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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
Water for a food-secure world Water for a food-secure world
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