Lake Tahoe --

Gov. Jerry Brown and the governor of Nevada signed a pact with the federal government near the shore of Lake Tahoe on Tuesday intended to increase the clarity of the lake by half a foot per year for the next 65 years.

The agreement seeks to make the lake visible to a depth of almost 100 feet by reducing the amount of fine sediment that enters the water each day. The states agreed to the goal with the federal Environmental Protection Agency, which will monitor the progress.

The pact to reduce pollution to the lake comes as the effort between California and Nevada to control development at the lake is threatened by a new law in Nevada that requires an easing of the threshold to approve new projects.

Jared Blumenfeld, the regional administrator for the EPA, said reaching the sediment reduction goal would require a considerable effort by many different entities.

"It's not by any means an easy goal," Blumenfeld said in an interview, "but we all concur that it is achievable."

It will fall largely on local agencies to take the steps to implement measures to reach the goal, which could come through advanced street sweepers and new infrastructure to capture the sediment in storm water runoff. Most of the sediment is attributable to the use of automobiles around the lake, Blumenfeld said.

Before signing the agreement, Brown and Nevada Gov. Brian Sandoval, a Republican, held meetings for two days at Lake Tahoe and said Tuesday they would visit each other's state capitol to talk with lawmakers about how California and Nevada will work together.

The cooperative relationship is threatened by a bill signed into law by Sandoval this year that would withdraw Nevada from the bistate Tahoe Regional Planning Agency, which has overseen development at the lake since 1969, unless the compact governing the agency is amended to make it easier for members of one state to approve new development projects. Such a change would have to be approved by both the California Legislature and Congress.

Also attending the annual Lake Tahoe summit were Sen. Dianne Feinstein, D-Calif., and Nevada's senators, Democrat Harry Reid and Republican Dean Heller.

Feinstein has been working to secure $415 million in additional federal funding to assist the effort, though she acknowledged that getting the money looks "very unrealistic." She said leaders should look to the private sector to raise money for lake restoration efforts and that she has set a goal of getting $300 million from those sources.

She also said getting California and Congress to agree to the mandates of the Nevada law would be "very difficult to achieve."