Dams

Few technologies have had more significant and persistent ecological impacts than dams. Almost every major river in the world has at least one large dam obstructing its flows. China alone has built over 22,000 large dams on rivers within its national territory, most of which have been constructed over the past three decades, and is nearing completion of the largest human-made structure in the world, the Three Gorges Dam. While varying in size and type, all dams share the goal of obstructing the flowing water of a river or stream in order to provide an array of perceived benefits to human communities. The most important of these include the conversion of flowing water into electricity (hydropower), the storage of water for irrigated agriculture, and the ...