Engineers are constructing a reservoir bigger than Manhattan to restore some natural water flow to the Everglades in an effort to revive the region's ecosystem, which is near ecological collapse after decades of flood-control projects designed to make the Florida wetlands suitable for homes and farms left the region parched.

The Everglades once covered more than 6,250 square miles but are now less than half that size. An influx of development and a 2,000-mile grid of drainage canals have caused 90 percent of the region's wading birds to disappear. Other creatures have suffered, too -- including 68 species that are considered threatened or endangered.

So crews plan to build the world's largest above-ground man-made reservoir, estimated to cost up to $800 million. Unlike most man-made reservoirs, which are built in existing canyons or valleys, this one will be contained within earth and concrete walls.

When completed in 2010, the shorelines will be 6 miles apart at the widest point, and the reservoir will hold up to 62 billion gallons of water. Planners hope to eventually double the size.

Some environmentalists oppose the project. The Natural Resources Defense Council has sued over the reservoir, saying the state has not legally committed itself to dedicating the water primarily to restoring the Everglades.

The state insists that 80 percent of the water will be used for environmental purposes, but some critics worry that without a legally binding agreement, the water could be used for other purposes, like agriculture or development (Brian Skoloff, Associated Press, May 6). -- RB