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COPING with EXTREMES The impact of Water Supply Infrastructure on floods and drought and the implications for food security Presentation from the International Centre for Environmental Management (ICEM) www.icem.com.au Mekong Challenge Programme on Water and Food: MK12: The impact of Water Supply Infrastructure on floods and drought in the Mekong region and the implications for food security MK12 is a project led by the International Center for Environmental Management (ICEM), working in partnership with the Institute of Water Resources Planning (IWRP – Vietnam), and the Enterprise Development Institute (EDI – Cambodia). This is a CPWF initiative funded with a grant from Australia through AusAID. The project runs from January 2012—December 2013. This presentation was from the CPWF 2013 Water, Energy and Food Forum bringing together the key stakeholders including regional water resource planners, WSI operators and downstream communities. This was an opportunity for the team to present their findings but also for the key stakeholders to discuss and debate the findings to reach a common consensus on recommendations for design and operation of WSI to enhance their contribution to food security. The hydrological regime of the Mekong Basin is characterised by variability. Between seasons, water availability varies by an order of magnitude; between years annual water availability can fluctuate by as much as +/- 30% from the average. While seasonal water variability driven by the monsoon has been instrumental in the productivity of the Mekong’s natural and human systems, the inter-annual variability expressed as droughts and extreme floods has had major adverse impacts on these systems and have even contributed to the demise of civilisations such as the Angkor of Cambodia. Water supply infrastructure (WSI) have been utilised for centuries in the Mekong Basin to regulate seasonal water availability and provide for consistent, year-round human use. For agriculture, water supply and more recently hydroelectricity, the storage of wet season flows for use in the dry season has led to tangible and significant improvements in livelihoods, agricultural productivity and energy security. However, having been designed and managed for regular climate, the performance of these WSI in managing extremes in hydro-climate is not well understood. Through research, modelling, surveys and case studies, this project will improve the understanding of the impact of WSI on managing floods and droughts and the downstream consequences for agricultural productivity and food security.
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COPING WITH EXTREMES THE IMPACT OF WATER SUPPLY INFRASTRUCTURE ON FLOODS AND DROUGHT AND THE IMPLICATIONS FOR FOOD SECURITY
Tarek Ketelsen, Simon Tilleard, Arun Parameswaran, Mai Ky Vinh
Assessing variability in the Angkor hydroclimate
Source: Buckley et al (2010)
• 1250-1450 extreme fluctuations in drought & storm conditions: mega-drought 1330s -1360s more severe but shorter drought
1400s -1420s Interspersed by high magnitude
monsoon years• Two severe droughts punctuated by heavy
monsoon rain weakened the kingdom by:– shrinking water supplies for drinking
and agriculture
– damaging Angkor's vast irrigation system which was central to it’s economy
Source: Day et al (2011)
“…the Khmer water management system is a vivid example of a sophisticated human technology that failed in the face of extreme (threshold) environmental conditions.”
Day et al, 2011
WSI expansion in the Mekong Basin
By 2030• Hydropower => quadruple• Irrigation command area => double• How will the Mekong’s current WSI handle extremes in
hydroclimate?
Key research questions1. Do WSI modulate the frequency and severity of droughts
and floods?2. How do descriptions of droughts and floods vary between
the various stakeholders and genders upstream and downstream of WSI infrastructure?
3. Have impacts of drought and floods diminished with dams and other WSI?
4. Through their effects on flood and drought, have WSI enhanced food security?
5. How can WSI design and management be improved to enhance their contribution to food security?
Main components of the study
1. Assessment of the Mekong flood & drought regime
2. GIS database of Mekong WSI and their capacity to regulate extremes
3. Regulating effects of WSI during hydroclimate extremes
4. Documentation of d/s community coping strategies during hydroclimate extremes
5. Implications for food security
Basin wide assessment• focus will be hydropower• regional review of floods and droughts and food security in
the Mekong Basin – Definitions of extreme hydro-climate conditions in the Mekong – Characterisation of their role in Mekong productivity
• develop a consolidated inventory of WSI in the basin. – Dam characteristics– Catchment characteristics– Downstream user characteristics.
Case study assessment• with Institute of Water Resource Planning (IWRP) and Enterprise
Development Institute (EDI)• selection based on preliminary findings of the basin-wide review &
consultations with key government agencies • select one WSI in Cambodia and one in Vietnam and conduct
computational modelling, community surveys and participatory consultations to understand how the downstream communities experience of floods and droughts have changed due to the introduction of WSI.
• develop an understanding of how WSI have impacted food security (both positive and negative) and scope implications of improvements to management.
Typical Reservoir Management for Electricity Generation:flood management considerations
1
2
3
4
Dry Season Wet Season
Full Supply Level
Low Supply Level
Live Storage
Dead Storage
Source: Räsänen et al, under publication
Allowance forFlood Storage??
1. Dry SeasonLow rainfall and plant operation begins to lower storage level
2. End of the Dry SeasonStorage level continues to drop towards Low Supply Level
3. Start of the Wet SeasonHigh rainfall causes storage level to rise
4. Dam at full capacityEarly wet season, Full Supply Level reached and maintained.
Storms
Storms and peak eventsAverage maximum daily
precipitation (1985-2005)
41%
25%
19%
15%
Source: MRC, 2010
Towards a flood control index….
1. Reservoir characteristics- Management and operational rules- Regulating Capacity (storage/MAF)- Spillway and plant discharge capacities- Freeboard capacity
2. Sub-catchment characteristics- Response time to storm events- Precipitation dynamics- Storm frequency and intensity- River flow and networks
3. Downstream considerations- Population Density- Land use characteristics- Infrastructure assets
Flood Control Index
Low capacity to regulate floods
High capacity to regulate floods
Towards a flood control index….
Thank you for your attention
