Of the approximately 49,000 major dams operating in the world, two-thirds are located in developing countries in Africa, Asia, and Latin America. The World Commission on Dams has chronicled both the economic benefits and the pervasive environmental damage attributable to large dams. This project is the logical and constructive sequel.
With our Global Initiative partners, the NHI is investigating the feasibility of re-operating some of these dams in order to restore a substantial measure of the formerly productive floodplains, wetlands, deltas and estuaries located downstream in ways that do not significantly reduce – and can sometimes even enhance – the irrigation, power generation, and flood control benefits for which the dams were constructed.
The Global Initiative Program pursues two converging lines of analysis. We are identifying the major dams where re-operating flood flows to emulate the natural hydrograph would produce the greatest benefits downstream in terms of restored floodplain ecosystems and human livelihoods such as fisheries, recessional agricultural, grazing, and other land uses dependent upon natural groundwater recharge.
Simultaneously, we are investigating the extent to which a “toolkit” of improved water management techniques can provide the targeted major dams with the flexibility in reservoir storage and release patterns necessary to reestablish environmental flow regimes. These water management techniques includ
- Reoperating irrigation reservoirs in conjunction with groundwater banks to generate surplus water supply and increase the flexibility in storage and release patterns to enable environmental flows to be re-established;
- Changing the role that hydropower dams play in the mix of generators serving an electrical grid so that the dam can operate on a run-of-the-river basis – storing and releasing water in rhythm with inflow patterns rather than electricity demand patterns; and
- Addressing floodplain development patterns to enable flood control dams to pass through rather than control, the smaller flood events, thereby re-establishing seasonal inundation of the floodplain to restore its environmental functions.
The project will feature regional feasibility investigations and reoperation demonstration projects, starting with China and West Africa, and expanding subsequently into Brazil (with The Nature Conservancy), India & Pakistan, and Eastern and Southern Africa. There is also the possibility of building a component in the Mekong basin in Southeast Asia in due course.
