The shortage of fresh water in the developing world is reaching critical levels. And a new dam in Brazil only serves to highlight the environmental problem...In many respects, the Castanhão dam exemplifies how a dam should be built. It involved detailed planning, and extensive consultation with the people whose homes in the nearby city of Jaguaribara were to be flooded. The planning also involved an assessment of the dam's environmental impact...As important as dams have been in the past, planners and politicians are now having to think of other ways to meet the problem of water shortages.