Session 2b: Hydropower, Irrigation and Multiple use: Experience from the Region

Mekong Forum on the Sustainable Development of Water, Food and EnergyPhnom Penh, Cambodia

7-9 December 2011

Environment as important water user for hydro-infrastructure’s

consideration

Great challenge on how to balance between water uses (development)

& protection of the poor’ s livelihood and integrity of

ecosystems

Ecosystem Services

Source: http://en.wikipedia.org/wiki/Ecosystem#Ecosystem_services

Ecosystem is a distinct ecological unit that includes both its living and non-living components that together function as a systemEcosystem services are “fundamental life-support services upon which human civilization depends,” and can be direct or indirect. The services and goods an ecosystem provides are often undervalued as many of them are without market value. Broad examples include:•Regulating (climate, floods, nutrient balance, water filtration)•Provisioning (food, medicine, fur, minerals)•Cultural (science, spiritual, ceremonial, recreation, aesthetic)•Supporting (nutrient cycling, photosynthesis, soil formation).

Adverse Environmental Impactsof Hydropower Development

Source: Adjusted from Good Dams and Bad Dams: Environmental Criteria for Site Selection of Hydroelectric Projects Working Paper (World Bank, 2003)

1. Flooding of Natural Habitats 2. Loss of Terrestrial Wildlife3. Involuntary Displacement4. Deterioration of Water Quality5. Change in D/S Hydrological Regime 6. Water-Related Diseases7. Fish and Other Aquatic Life8. Floating Aquatic Vegetation9. Loss of Cultural Property10. Reservoir Sedimentation11. Greenhouse Gases

Figure: http://www.xlhbw.net/en/xgcal.asp?pid=41

These can be minimized by good dam site selection!

http://mekong-tourism.com/1491-mekong-queen-cruise/

Change in Downstream Hydrological Regime Impacts: • Affect riparian ecosystems dependent on periodic natural flooding, increase saltwater

intrusion, increase river-edge and coastal erosion & damage the biological and economic productivity of rivers and estuaries.

• Damage agriculture and human water supplies

Mitigation measures: • Objectives to consider in optimizing water

releases include adequate downriver water supply for riparian ecosystems, reservoir and downriver fish survival, reservoir and downriver water quality, aquatic weed and disease vector control, irrigation and other human uses of water, downriver flood protection, recreation, and power generation.

• The ideal release pattern would closely mimic the natural flooding regime. Dams that generate baseload electricity are typically more capable of replicating near-natural downriver flows than those that produce peaking power.

• Environmental management plans for hydroelectric projects should specify environmental water releases.

Mitigation measures: • Management of water releases are needed for the

survival of certain fish species. Fish passage facilities are intended to help migratory fish move upriver past a dam but are usually of limited effectiveness. Fish hatcheries can be useful for maintaining populations of native species which can survive but not successfully reproduce within the reservoir. Fishing regulation is often essential to maintain viable populations of commercially valuable species, especially in the waters immediately below a dam where migratory fish species concentrate in high numbers and are unnaturally easy to catch.

Fish and Other Aquatic LifeImpacts: • Even reservoirs positively affect certain fish species by increasing the area of available

aquatic habitat but the net impacts are often negative because (a) the dam blocks fish migrations; (b) many river-adapted fish and other aquatic species cannot survive in artificial lakes; (c) changes in downriver flow patterns adversely affect many species, and (d) water quality deterioration in or below reservoirs kills fish and damages aquatic habitats. Freshwater molluscs, crustaceans, and other benthic organisms are even more sensitive to these changes than most fish species, due to their limited mobility.

Reservoir SedimentationImpact: • Live storage and power generation are reduced by reservoir sedimentation, such that

much of some projects’ hydroelectric energy might not be renewable over the long term.

Mitigation measures: • Watershed management can minimize

sedimentation and extend a reservoir’s useful physical life, through the control of forestry, road construction, mining, agriculture, and other land use in the upper catchment area. Protected areas are sometimes established in upper catchments to reduce sediment flows into reservoirs, as in the proposed Nam Theun II (Laos) project.

• Other sediment management techniques for hydroelectric reservoirs may at times be physically and economically feasible e.g. upstream check structures, protecting dam outlets, reservoir flushing, mechanical removal, and increasing the dam’s height.

Conclusions• Environment represents a viable and important user

of water resources, and needs to be built into hydropower planning, investment and coordination

• Multi-purpose potentials including water for environmental services should be taken into account in scheme design, investment and operation for maximum total benefits

• For planning phase, good site selection can minimize the potential environmental impacts

• Water should be managed with:– reservoir management rules to ensure minimum

environmental flows and maximum total benefits– Integration of hydro-infrastructures into IWRM/River

Basin Planning

Thank you for your attention!

Source: http://www.boston.com/bigpicture/2011/10/thailand_flood_reaches_bangkok.html

Difference between Ecosystem and Environment

The terms environment and ecosystem are often used interchangeably. However, the two terms differ dramatically in their ecological definitions. Generally, an ecosystem consists of different environments, whereas an environment is fleeting. The key lies in how the two function and their relationships with the plants and animals each contain.

Ecosystem Features: An ecosystem is a distinct ecological unit that includes both its living and non-living components that together function as a system.

Environment Definition: In ecological terms, an environment is defined as the total surroundings of an organism, but it does not imply any ecological relationships between members.

Permanency: An organism's immediate environment changes as it moves from one point to another, whereas the ecosystem remains the same no matter where the organism travels within it.

Function: An ecosystem depends upon essential life processes such as photosynthesis for its existence, while an environment is merely a place in time.

Differences: The components of an ecosystem as a whole define what an ecosystem is, whereas an organism determines its own environment.

Read more: Difference Between an Environment & an Ecosystem | eHow.com http://www.ehow.com/facts_5771440_difference-between-ecosystem environment.html#ixzz1fgHJ9goB