FIRTH — The demolition of a Snake River bridge may kill some endangered Utah Valvata snails, but not enough to cause their extinction, the U.S. Fish and Wildlife Service concludes.

The Idaho Department of Transportation halted removal of the old bridge in October to evaluate the project´s impact on the mollusk.

The tiny snail was not believed to exist along the river north of American Falls, but discoveries in the last year have indicated otherwise.

The Army Corps of Engineers still needs to review the biological opinion before approving a federal permit that will allow the job to continue.

Transportation environmental planner Denise Stark expects it to take one to two weeks to get the permit.

Joe Cannon, the contractor, said spring´s higher water levels may delay work until the summer.

“We need to resolve that as soon as we can,” said David Babbitt, director of the Bingham County public works department.

The Utah Valvata snail is one of five endangered mollusk species downstream in the King Hill area that have pitted environmentalists against agricultural interests for years.

Agricultural groups are concerned the federal listing could impact the delivery of irrigation water to farmers and ranchers.