SALEM, Ore. — A bill to impose a surcharge on PacifiCorp customers to pay for removal of four hydroelectric dams on the Klamath River was endorsed Tuesday by the Oregon Senate. The bill goes to the House.

The legislation is needed to put into effect an agreement among farmers, fishers, tribes and others to improve salmon runs and settle a lengthy water struggle in Oregon and California’s Klamath Basin.

Under the measure, up to $180 million would be collected from PacifiCorp’s 500,000 Oregon ratepayers to go toward dam removal. Another $20 million would come from the utility’s customers in California.

The utility estimates the average residential customer would pay an extra $1.50 a month.

The 18-12 Senate vote fell mostly along party lines, with Democrats supporting the bill and Republicans opposed.

The only GOP ‘yes’ vote came from Sen. Jason Atkinson of Central Point, who said the bill would provide stability for agriculture in the area and avoid the larger expense of keeping the dams and upgrading them to win a new federal license.

“There is no status quo. The brave thing to do is to move this forward,” said Atkinson, who’s a a fourth-generation Klamath River landowner.

The measure was opposed by GOP lawmakers — and Democratic Sen. Rick Metsger of Welches — who worried about cost overruns and whether ratepayers or taxpayers might be saddled with those extra costs.

Metsger said he wants to protect salmon runs, but utility ratepayers as well.

“This bill does not cover unknown liabilities that could result from the dam removal,” he said.

The bill stems from a decades-long dispute over the dams, which block fish passage and are blamed for water quality problems in the Klamath River.

Last fall, Kulongoski signed a tentative dam removal agreement with California, the federal government and PacifiCorp, which owns the four dams. Dam removal is scheduled to begin by 2020, although other steps are required before that happens.

Kulongoski’s natural resources adviser, Mike Carrier, said after Tuesday’s vote that fears about ratepayers or taxpayers being saddled with unforeseen costs are unfounded.

Under the agreement, he said, the states would have the ability to opt out of the dam removal program in 2012 if a federal analysis of the removal project shows it would be more expensive than anticipated.