The strategy developed by federal agencies and state officials in Nevada, Arizona and California seeks to protect 26 endangered or threatened species, its supporters said.

It is also aimed at reducing the threat of environmental lawsuits against the states for taking water from the river.

"Through implementation of this program, the likelihood of a water conflict on the Colorado River is reduced," Robert Johnson, commissioner of the Bureau of Reclamation, said in support of the bill.

After Tuesday's hearing in the House water and power subcommittee. Rep. Dean Heller, R-Nev., a co-sponsor of the bill along with Rep. Harry Mitchell, D-Ariz., said he expects it to pass with minor changes.

"Passage of this bill would help our state better manage its scarce water resources, protect our environment and provide for our future," he said.

The Department of Interior signed off on the plan in 2005 after river officials, utility authorities and environmental groups united in 1997 to create the Lower Colorado River Multi-Species Conservation Program.

George Caan, executive director of the Colorado River Commission of Nevada, called the plan an unprecedented arrangement balancing water and restoration needs.

Habitats constructed from Lake Mead to the U.S-Mexico border would be used to restore populations of endangered fish such as razorback suckers and bony-tailed chubs.

But critics said the plan ignores other species such as the Colorado pike minnow because it is not found in the lower reaches of the river.

Although initially supportive in 1997, conservation group Defenders of Wildlife later dropped its support because the river program didn't offer enough protections for other species and because it didn't include the flexibility to cope with climate change, said Kara Gillon, senior attorney for Defenders of Wildlife.

"It's not a true river restoration program because it doesn't address the causes of the river's decline," Gillon said.

The program would cost $626 million, which would be shared among 50 federal and state agencies. Federal entities would pay half through appropriations by Congress.

Of the remainder, California would pay 50 percent while Nevada and Arizona would split the other half. Nevada's share would be $78 million.

Rep. Grace Napolitano, D-Calif., the subcommittee chairwoman, said she supports the bill, but she criticized its 50-year duration.