"The beauty of Lake Tahoe is unparalleled," Reid said. "We must do everything we can to keep it that way."

The bill before Congress includes money for projects to improve water quality, reduce wildfire threats, combat aquatic invasive species and build new public transit systems featuring ecologically friendly roads.

Obama said in his address that tourist-based economies like the one at Tahoe "live or die by the health of the environment."

The bipartisan cooperation at the lake is evidence "there's no contradiction between being smart on the environment and having a strong economy," he said.

Sen. Dianne Feinstein, D-Calif., praised efforts by Sen. Dean Heller, R-Nev., to gather Republican support for the bill.

Feinstein said she's most impressed by the more than $330 million the private sector has contributed to the effort that has restored 1,500 streamside zones and added 2,700 linear feet of shoreline to public access areas.

She noted, however, that experts recently warned Tahoe is warming faster than any large lake in the world due to climate change.

"This red flag reminds us why additional funding is vital to preserve the pristine nature of Lake Tahoe," she said.

Underwater visibility stretched to a depth of 105 feet in 1968 when scientists first measured it by lowering a white, dinner-plate-size disk into the water until it disappeared. Clarity worsened by 30 percent over the next three decades — about a foot a year — falling to a record-poor 64 feet in 1997.

Since then, the loss of clarity has slowed, registering 73 feet last year. The long-term goal is to get back to 100 feet, with a short-term goal of 78 feet by 2026, sustained for five years.

Feinstein, who grew up in the San Francisco Bay Area, and Heller, former chairman of the Tahoe Regional Planning Agency, have been visiting the lake since they were children.

"With five generations of Hellers enjoying the Lake Tahoe Basin, this bill hits close to home for me," Heller said.