Search For Rare Snail Slows Pace Of Bridge Building No Sign Of Habitat Found For Endangered Utah Snail

Engineers had to search last week for a snail smaller than a thumbtack before moving forward with plans to build a $4.4 million bridge across the Snake River.

No signs of the snail’s habitat were found underneath the Overland Bridge, which eventually will be replaced with a new, four-lane structure.

Federal environmental laws required the Idaho Transportation Department to probe for the endangered Utah “valvata” snail before building.

Finding snails there would have been a good sign for the river’s health if the probe had uncovered the snail’s habitat.

“If we’re taking care of snails, then we’re taking care of ourselves,” said Marilyn Hemker, a U.S. Fish and Wildlife biologist in Boise.

The snail was listed as an endangered species in 1993 along with four other Snake River snails, Hemker said. The Utah valvata snail exists only in high-water-quality springs, she said.

“If we lose these snails it’s a sign we’ve lost good quality water in the Snake River, and then we all suffer,” Hemker said.

Mike Etcheverry, a water quality specialist with the Division of Environmental Quality in Twin Falls, said biologists submerged a “hydrolab” in the river to search for signs of snail habitat. The lab’s computerized probes checked for changes in water temperature that can pinpoint spring water, which is warmer than the river, Etcheverry said. No signs of springs were found.

Even if habitat had been found there, biologists did not expect to come across the snail because of poor water quality, Hemker said.

The snail has been discovered in areas between American Falls and Hagerman, and it was found in 1992 in Lake Walcott above Minidoka Dam, Hemker said.