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Anonymous (1978). Environmental issues in river basin development. Pages 1163- 1172 in U. Nations, ed. Water Management and Development, Proceedings of the United Nations Water Conference, Mar del Plata (Argentine), Pergamon Press.

Environmental effects of dam construction in river basins and methods of minimizing such effects are described. Large dams tend to have particularly significant and complex effects on aquatic ecosystem which must be carefully evaluated prior to construction. Rational development involves: (1) a comprehensive basinwide assesment of social, economic, and ecological characteristics and of the effects of development; (2) evaluation of development alternatives reflecting social, economic, and environmental factors to provide the basis for environmental management. Dam construction can provide the water supply, hydroelectric power, and flood control, and can greatly improve agriculture, forestry, and livestock management. Excessive use of water and agricultural chemicals can however, cause waterlogging and salinization, and can affect water quality and quantity. Dams produce a permanent physical transformation, inundating settled areas and destroying habitats , affecting the groundwater regime and water table, possibly increasing seismic tendencies, and often leading to explosive aquatic weed growth and the spread of schistosomiasis and other communicable diseases. Dams in tropical areas tend to favor weed propagation and vectors of parasitic diseases, while temperate-zone dams often interfere with fish migration. Resettlement of population displaced by dams often leads to housing, disease, and social problems. Loss of wetlands endangers many plant and animal species.