Dam builders to learn from earlier blunders

Press, 28 March 1981, Page 14

Dam builders to learn from earlier blunders

By

THOMAS LAND

in London

Tanzania is planning ai vast new dam on the Rufiji River — but before work starts it is taking steps to avoid, the ecological blunders made by other African dam-builders. It has commissioned an environment impact study whose findings are an A-to-Z of everything that could go wrong. The Rufiji is Tanzania’s largest river, its basin covering about one-fifth of the country with perhaps a tenth of the national population living there. Construction of the dam is expected to begin next year. The main aim is to provide electricity, but the dam will also decrease agriculture’s dependence on seasonal flooding and will create facilities for year-round water transport in the basin.

“Hydro-electric dams are becoming essential development projects in the face of dwindling fossil fuels,” says a specialist from the United Nations Environment Programme, which carried out the study for the Rufiji River Basin Development. Authority. “But when man superimposes water over extensive terrestrial systems, he creates new and unfamiliar systems and biological associations oyer which he has little or no control.”

To begin with, the dam is likely to affect the animal population of Tanzania’s biggest game reserve, Selous, where there are 90,000 elephants, 20,000 hippos and an abundance of lion, rhino, leopard, zebra, impala and crocodile. .They will have to be ’protected.

Declining soil fertility may ■ result from the greatly reduced flow of silt to the flood plain. There, is also the danger of •

spreading aquatic weeds. Many species of fish, whose life cycles include essential periods of migration, will be prevented from travelling downstream. The mangrove forests, which abound in the river valley and provide local timber supplies, may also be seriously affected by the drying of the delta. Finally, there is the socioeconomic effect of large-scale dam building in developing regions, covered at great length by another report prepared for the World Conference on Agrarian Reform and Rural Development, held recently in Rome. A special list of the U.N. Food and Agricultural Organisation says that “the idea of new agricultural communities on virgin or reclaimed land, often a by-product of huge new dam projects, has always had a tremendous appeal with Gov- f

ernments. in part because new lands offer an alternative to thorny problems of agrarian reform in settled areas.” Actual experience seldom justifies these hopes. Among the practical problems, described by the report were resentment among- local people to the wave of settlers attracted by development; lack of social amenities; lack of non-agricultural work in the new communities: and excessively rigid direction by central bureaucracies. Given the conflicts between the long-term needs of the environment and the shortterm needs of large populations for increased supplies of food and fuel, The Tanzanian compromise may well attract the attention of development planners everywhere. — Copyright, London Observer Sert vice. •<- j