By BRIAN SKOLOFF
Associated Press Writer

WEST PALM BEACH, Fla. (AP) -- Construction on a huge reservoir meant to help restore the Everglades will be put on hold over a lawsuit brought by a group that fears the water could be diverted for other purposes.

The South Florida Water Management District, whose board voted Thursday to stop work, has already spent about $250 million on construction. The delay could cost nearly $14 million.

The 25-square-mile reservoir - the largest of its kind in the world - is estimated to cost up to $800 million and was set for completion in 2010.

No one disagrees that storing runoff water is key to reviving the famed River of Grass. But the Natural Resources Defense Council is suing, claiming the state has not legally committed itself to using the water primarily for restoration.

The state insists that at least 80 percent of the water will be for environmental purposes, but critics fear that without a legally binding agreement, the water could be sent elsewhere for agriculture or development.

Council attorney Brad Sewell said the intent of the lawsuit is not to stop construction, but to bind the district legally to a resolution passed last year by its own board agreeing that the water would be used mostly for the environment.

The water district fears that if a federal judge revokes its permits for the project because of the lawsuit, millions of dollars could be lost.

"It will be much more expensive if we got into the middle of this contract and then all of a sudden it gets shut down," district spokesman Randy Smith said. "The board's decision was made solely on prudent financial responsibility to the taxpayers."

The district board anticipates construction could be halted through the end of the year. The board agreed to stop construction as of June 1 and begin paying its contractors $1.9 million for each month the project is delayed, up to $14 million by the end of 2008.

Water once flowed practically unhindered from the Everglades headwaters south of Orlando all the way to Florida Bay. But now when a hard rain falls, canals direct the overflow into the ocean to keep it from inundating 5 million people who have settled in the area. It also has left the wetlands near ecological collapse.

The reservoir's purpose is to store water that would normally be channeled out to sea and divert it to the Everglades at various times.