The construction of dams can often have catastrophic consequences, according to a research paper from the environmental group World Wildlife Federation.GLAND, Switzerland, CH, 2001-08-07 [SolarAccess.com] The construction of dams can often have catastrophic consequences, according to a research paper from the environmental group World Wildlife Federation. Dams are often designed with a very poor knowledge of the potential for extreme flood events, says the report, ‘Dams and Floods.’ Where data do exist, they may fail to consider current risks, such as increased rainfall due to climate change or increased run-off of water due to deforestation or the drainage of wetlands. “Dams carve up landscape like a jigsaw puzzle in the name of providing benefits to people,” says WWF’s Biksham Gujja. “But the pieces often never fit again and fragmented nature can result in greater losses for generations to come.” The loss of natural sponges for floodwaters within river basins increases the risk of extreme floods, and WWF argues that many problems could be avoided if the recommendations of the World Commission on Dams were applied to future dam projects. Lack of adequate information means that dams are often built without adequate spillways to cope with extreme floods, according to author Fred Pearce. In a 1995 study of 25 dams in India, World Bank engineers calculated the amount of water that the dams should be able to release at the height of a flood. In each case, they found the expected floods were greater than those that the dams had been built to discharge over their spillways; two could cope with only one seventh of expected peak discharge. Dam managers often wait too long to make emergency releases of water above natural flooding levels, at times of high rainfall and during exceptional river flows. The report says the primary purpose of the dam is to generate electricity and provide water for cities, as well as preventing flooding downstream. Where dams must be built, WWF recommends that the storage and release of water be in tune with the natural river system and the needs of people who rely on the river, such as fishing communities and floodplain farmers.