Pettit Lake Creek Weir

Restoration work on a once vital breeding habitat for Snake River sockeye salmon.

In the 1960s, a new barrier blocked the Snake River sockeye salmon species’ 900-mile migration route. As a result, the 150,000 sockeye salmon returning to central Idaho each year felt to just four by the 1990s, leading to the Shoshone-Bannock Tribes leading an effort to list the salmon as an endangered species.

The new weir, which removes an historic design flaw in the 1960s weir, re-opens the river for a healthy future for the sockeye, marking a critical restoration point for the tribe and region’s biological and cultural heritage.

To achieve that, an innovative design for the weir helps biologists gather data on both juvenile and adult fish heading to and from the lake. The design handles increased water flows, its precast concrete and weathered steel structure simplified construction, avoiding the collecting of debris.

The project team worked alongside the Shoshone-Bannock Tribe, Bonneville Power Administration, U.S. Army Corps of Engineers, Idaho Department of Fish and Game and the U.S. Forest Service to deliver the one-of-a-kind project. Constructed through the summer, while the creek levels were low, the project team completed the project in time for the annual migration.