WATER STORAGE FOR CLIMATE RISK
MANAGEMENT
VLADIMIR SMAKHTIN
International Water Management Institute,
Colombo, Sri Lanka
Third Annual CCAFS Science Workshop
Copenhagen, Denmark, 1 May 2012

WATER SCARCITY AND CLIMATE CHANGE
1/3 of the world’s population live for basins that have to deal with water scarcity
Water in a food-secure world

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 STORAGE CONTINUUM
Water for a food-secure world

RE-THINKING LARGE STORAGE
Ethiopia GDP vs Rain Storage per capita
Water for a food-secure world

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

EVALUATING STORAGE OPTIONS
Basin scale analyses Site level analyses
Evaluation of climate change Understanding storage at the local
impacts on storage at basin scale (economic, socio-political aspects)
(Hydro and WR Models)
Evaluation metrics
to assist in planning and
management of storage
Water for a food-secure world

MAPPING THE NEED FOR STORAGE
Livestock storage need
Based on Poor rural population density,
Livestock density, amount of rainfall,
variability of rainfall
Water for a food-secure world

FOCUSING ON GROUNDWATER
Water for a food-secure world

GROUNDWATER AS ADAPTATION OPTION –India
Groundwater use in Asia District-wise stage of GW development (%)
India
USA
China
Bang., Pak
W. Europe
VN, SL
Source: CGWB, 2004
Water for a food-secure world

GROUNDWATER AS ADAPTATION OPTION –India
Managed Aquifer Recharge vs other storage options
Measurable criteria Small Large Managed
Surface Dams Aquifers
Storage
Water where needed 3 2 5
Water when needed 1 2 5
Level of water control 1 2 5
Non-beneficial losses –e.g. -4 -2 -1
evaporation
Protection against a single 1 2 5
annual drought
Protection against -1 1 4
successive droughts
Ease of recovery during 5 4 3
monsoon
Other
Water for a food-secure world

STORING FLOODS
Current Situation – Dry Season
Water for a food-secure world

STORING FLOODS
Current Situation – Wet Season
Water for a food-secure world

STORING FLOODS
Possible Future – Wet Season
Water for a food-secure world

STORING FLOODS
Subsurface Solution
Water for a food-secure world

STORING FLOODS
Chao Phraya River Basin, Thailand
Harvest Floods Do Not Harvest
Water for a food-secure world

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
Water for a food-secure world

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
18
Water for a food-secure world