SANDPOINT - Stopgap repairs to the troubled timber breakwater at the north end of Priest Lake will not be able to ward off its demise, according to a study commissioned by Bonner County.

The 1,300-foot-long breakwater was built in 1917 and has suffered several partial failures over the past 20 years. The breakwater has been repaired, but remains doomed, the study by Coast & Harbor Engineering and GeoEngineers concluded.

"While periodic repairs to the breakwater have kept the structure operational, without substantial improvements, failure of the breakwater is imminent," the study said

The breakwater shields the Thorofare connecting Upper Priest Lake and the lower lake, but wave energy still manages to penetrate the channel and north shore. Breaches in the structure allows sediment to infiltrate the Thorofare and cause shoaling.

Erosion on the south side of the breakwater is increasing wave reflection and exacerbating bottom scouring that will ultimately lead to the structure's failure, according to the study.

The feasibility study recommends replacing the breakwater with a sloped structure armored with rock, which is estimated to cost between $800,000 and $1 million to build.

The county has not identified a source of funding to construct the project, said Leslie Marshall, director of the county's waterways department. Nor has the county identified funding for the project's review under the National

Environmental Policy Act, which could cost $75,000 to $100,000 under a best-case scenario.

A favorable outcome of the NEPA analysis is by no means guaranteed, although Jason Scott of GeoEngineers told commissioners on Tuesday its chances of obtaining a permit would be "pretty good" if a solid environmental assessment was conducted. If permitting agencies require a more thorough environmental impact statement, the NEPA costs could increase substantially.

It's also unclear what opposition the proposal might encounter.

"You just never know what the opposition is going to do until you get it out there," said James Harakas of GeoEngineers.

Opponents of powerboats on Upper Priest Lake, for instance, could thwart the replacement project because continued sedimentation in the Thorofare could render it accessible only by paddlers.

County commissioners and waterways officials took the study under advisement.