Of all mankind's efforts to harness nature for the greater good, none - from the Lower Snake River in the Pacific Northwest to the ponderous Narmada running through central India - have proved so dangerously mixed a blessing as large dams.
The mighty symbols of modernity for some, harbingers of catastrophe for others, the huge dams that now block or divert more than half the world's rivers have brought with them far more than just the water and electricity they promised.
Often flooding poor peasants out of their homes so that wealthier town dwellers can have light and water, dams raise "issues of equity, governance, justice and power - issues that underlie the many intractable problems faced by humanity" in the words of a report issued Thursday.
The report, launched in London by former South African President Nelson Mandela, is the work of an international group of independent experts who have written a stinging indictment of the way large dams have been built over the past half century. But they also propose fairer and less disruptive ways of managing the planet's key resource - water - in the next century.
Mr. Mandela praised the World Commission on Dams report Thursday. "It is one thing to find fault with an existing system," he said. "It is another thing altogether, a more difficult task, to replace it with an approach that is better."
The report finds that although dams "have made an important and significant contribution to human development ... in too many cases an unacceptable and often unnecessary price has been paid to secure those benefits."
After two years of work around the world, the 12-member commission reached its conclusions unanimously - remarkable for a group that ranged from Goran Lindahl, head of the engineering giant ABB that has built many dams, to Mehda Patkar, a leading antidam activist.
Dam critics generally welcomed the report. "It vindicates a lot of the things we have been saying" says Patrick McCully, Campaigns Director for the International Rivers Network, who is part of the global movement that urged the commission's creation. "We are very pleased with the report, and we want its recommendations to be implemented."
Future dam projects, the report argues, must be governed by five core values: equity, efficiency, participatory decisionmaking, sustainability, and accountability. And better management of demand for water and electricity could reduce the need for new dams.
Suggestions include erecting more small-scale (micro-hydro) dams, bolstering conservation efforts, and expanding wind-and solar-power projects.
The reservoirs behind the 45,000 large dams built around the world so far have forced as many as 80 million people out of their homes, the commission estimates, more than half of them in India and China where titanic dams are still being built on the Narmada and Yangtze Rivers. Case studies showed that "the direct adverse impact of dams have fallen disproportionately on rural dwellers, subsistence farmers, indigenous peoples, ethnic minorities, and women."
Large dams also "have many, mostly negative impacts on ecosystems," the report finds. They have wiped out species and worsened global warming as rotting vegetation creates greenhouse gases.
At the same time, the $2 trillion invested worldwide in large dams over the past 50 years have not always proved even economically worthwhile. The report found that "a considerable portion [fell] short of physical and economic targets." Overall, dams contribute to 19 percent of the world's electricity and 16 percent of food production.
In the future, the commission urged, everybody who might be affected by a dam - from government officials and peasant farmers to funding agencies, fishermen, and engineers - must be part of the decisionmaking process.
That has been the commission's own experience in what its chairman, South African Education Minister Kader Asmal called "an extraordinary journey of learning and reflection" by people from a wide range of backgrounds and opinions.
"This impressive report shows that there is common ground that can be found among people of good faith coming from very diverse starting points" says James Wolfensohn, president of the World Bank, which was once a major funder of big dams, and which sponsored the commission along with the World Conservation Union (IUCN).
"It means nothing to build billion-dollar dams if your monuments alienate the weak," says Mr. Asmal. "It means nothing to stop all dams if your protests only entrench poverty. But show me a clear and sustainable way to provide food, energy, stability, and running water for those who need it most - that means something."
Some antidam activists are cautious. "All the agencies involved in funding dams have become masters at writing noble-sounding policies and humane-sounding declarations that have nothing to do with the situation on the ground," says Arundhati Roy, a popular Indian novelist who has been prominent in the campaign against dams on the Narmada.
"Whether the World Commission on Dams report remains on paper or if any part of it is implemented remains to be seen. I just hope it isn't just another document," she adds.
But, the commission has already had an effect, says Mr. McCully. The US Export-Import Bank, which has funded many large dams built by American firms in developing countries, and the African Development Bank have both said they will respect the commission's guidelines and not fund dams that do not follow them.
"With public pressure," McCully predicted, "things can happen."
(c) Copyright 2000. The Christian Science Publishing Society