Thomas Fork Unit
Wetland Enhancement Project
Bear Lake County, Idaho

Ducks Unlimited (DU) partnered with the U.S. Fish and Wildlife Service (USFWS) and Idaho Fish and Game (IDFG) to replace a water control structure on the Thomas Fork Unit of Bear Lake National Wildlife Refuge enhancing more than 1,100 acres of wet meadow habitat. Thomas Fork WPA is situated in southeast Idaho and serves as a critical resource in the Pacific Flyway, particularly for distinct Rocky Mountain populations of birds such as the Lesser and Greater Sandhill Cranes. The Thomas Fork Unit is a floodplain system hydrated by the Thomas Fork of the Bear River through natural flood regimes and augmented by flood-irrigation infrastructure. The Unit is surrounded by flood-irrigated livestock pasture on all sides increasing its resource footprint to more than 1,500 acres. These pastures provide additional bioenergetic resources for migrating and breeding waterfowl and waterbirds.

The unit has been historically managed by a singular water control structure on the Thomas Fork. Overtime that structure had fallen into disrepair and was not functioning properly. The USFWS approached DU to provide engineering assistance in the development and implementation of a new water control structure. DU partnered with IDFG to cost-share the engineering services. Engineering design was conducted over the summer of 2015 and the structure was installed later in the fall. The new structure maximizes water-use efficiency in the system and is expected to provide increased floodplain distribution of surface water and prolonged flooding through the system benefiting livestock producers, aquifer recharge, and wetland obligate birds and wildlife. Additionally, the prolonged flooding regime is expected to increase late season in-stream flows in the Bear River benefitting Bonneville cutthroat trout.