Engineers next month will begin building one of the world s largest manmade reservoirs -- the size of a small city -- as efforts continue to restore natural water flow to the Everglades. The reservoir, roughly 25 square miles in area, is set for completion in 2010. It will hold 62 billion gallons of water, equivalent to about 5.1 million residential swimming pools, and will be seven miles across at its widest point.

Most reservoirs are built amid mountains and valleys or where a natural water source feeds the pool. In this case, 30 million tons of earth will be dug from flat land and surrounded by a 26-foot high, 21-mile long levee, making it larger than any other reservoir not connected to a natural source, according to state officials.

"When you stand on one side of this reservoir, you will not see the other side," said Carol Wehle, executive director of the South Florida Water Management District, the agency charged with managing Everglades water. The so-called "flagship" project is part of the overall 30-year, $10.5 billion federal-state partnership in the worlds largest wetland restoration effort.

Decades of dikes, dams and diversions have left the Everglades in a state of sickness. Lake Okeechobee, once the vast wetlands liquid life source, has been encircled by a dike, its waters now laden with high levels of phosphorous from farms and suburban sprawl. The nutrient is choking life from the ecosystem.

And because officials have historically had few places to store water, Lake Okeechobee is maintained at a higher than optimal level, which keeps sunlight from reaching vital vegetation on the lake s bottom.

The $400 million, 16,700 acre reservoir will allow water managers to redirect storm drainage, lowering Lake Okeechobee levels and reducing pressure on its aging earthen dike. The diversion will also minimize the need for damaging deluges let loose through the St. Lucie and Caloosahatchee estuaries that feed into the Atlantic Ocean and the Gulf of Mexico.

The stored water will also provide nourishment for the Everglades during dry seasons. "Water storage is a key element to the restoration process, not only for controlling water releases but also for flood protection and wildlife habitat restoration," said Colleen Castille, secretary of the Florida Department of Environmental Protection.

The federal government approved the permit for construction last week. "Right now, we have too much water in Lake Okeechobee most of the time," said Audubon of Floridas Chris Farrell. "It s going to help take a little bit of water off the lake, not as much as wed like, but its a start." The massive reservoir, which will be nearly doubled in size in the coming decades, is part of the states Acceler8 program intended to hasten efforts to restore life to the Everglades.

The overall plan will eventually encompass two additional, smaller reservoirs near Lake Okeechobee. "Everglades restoration is about quality, quantity, timing and distribution," Wehle said. "It takes all of the projects working in concert with each other to restore the Everglades."
(Por Brian Skoloff, Environmental News Network, 21/07/2006)