GRANTS PASS, Ore. -- Worried they will be found in violation of the Endangered Species Act, the U.S. Army Corps of Engineers said Friday they will cut a notch in the Elk Creek Dam on a tributary of the Rogue River to allow threatened coho salmon to swim freely to spawning grounds.

"This plan solves the fish passage issue with a biologically sound, long-term plan," Col. Thomas O'Donovan, Portland District engineer for the corps, said in a statement.

He said relying on a temporary fish trap facility to haul salmon around the dam "is no longer an option."

The corps has been trapping salmon and steelhead at the base of the dam, located about 30 miles north of Medford, and hauling them upstream in trucks since 1987 at a cost of $220,000 a year. Facilities designed to last about five years during dam construction have been used for 20, said corps spokeswoman Amy Echols.

Plans call for starting construction next summer. The project is estimated to cost $10.4 million.

The corps first proposed notching the dam in 1997 as the most cost-effective solution to a continuing problem, but local leaders opposed it, worrying that the dam would never be completed. Successive members of Congress backed them up.

What has changed is that U.S. Rep. Greg Walden, R-Ore., no longer has the influence in a Democratic-controlled Congress to block funding, said Andy Kerr, a senior consultant to Oregon Wild, the environmental group that won a court order stopping the dam after it was half built.

"The Elk Creek Basin in the Upper Rogue is only 10 percent of the watershed, but it provides over 40 percent of coho salmon numbers," said Kerr.

He called the Elk Creek Dam project "such a rancid piece of pork ... that the best deal for taxpayers and the best deal for salmon is to notch this dam."

Walden spokesman Andrew Whelan did not immediately return calls for comment.

The corps has notified Walden of the proposal, and he has not voiced opposition to it, said Echols.

The dam was first authorized by Congress in 1962 as part of a three-dam flood-control project for the Rogue River Basin.

Construction was halted at the halfway point in 1987 after environmentalists won a federal injunction based on the corps' failure to assess impacts on Rogue River salmon and steelhead.

In 1995, the corps abandoned the project after spending $100 million. Two years later it proposed partial demolition to enhance fish passage. But former U.S. Rep. Bob Smith, and then his successor -- Walden -- were able to block it.