Poison Creek and Kinnikinic Creek Aquatic Organism Passage Improvement Project

The Idaho Department of Fish and Game will replace a partial fish passage barrier on Poison Creek under State Highway 93 and a complete fish passage barrier on Kinnikinic Creek under State Highway 75 to provide year-round passage for all life-stages of Endangered Species Act (ESA) listed Snake River Spring/ Summer Chinook Salmon and Snake River Summer Steelhead. Poison Creek and Kinnikinic Creek are tributaries to the upper Salmon River in central Idaho.



The Poison Creek culvert is a corrugated steel pipe culvert at the mouth with a significant drop into a rip rap cascade at all flows below high water. In years with low snowpack, high water is not sufficient to connect Poison Creek to the main Salmon River. The project will replace the steel culvert with a single span prestressed voided slab bridge with pile-driven foundations and re-route Poison Creek to provide fish passage at all flows for all life-stages of ESA listed steelhead, Chinook Salmon, Sockeye Salmon, and Bull Trout.



Kinnikinic Creek currently flows into the main Salmon River through a smooth bottom concrete box culvert. There is currently no passage into Kinnikinic Creek, and the project will re-place the box culvert with a single span prestressed bulb tee girder bridge. The site will require significant channel work and excavation because the stream is relatively high gradient. Three up-stream culverts are flow-dependent partial migration barriers, and partners are developing a fish passage project to replace those barriers.

Replacing the Poison Creek Highway 93 culvert with a bridge will provide year-round access to 6.7 miles of spawning habitat for steelhead and rearing habitat for Chinook Salmon, Sockeye Salmon, and steelhead. Replacing the Kinnikinic Creek Highway 75 culvert with a bridge will provide fish full fish passage to the lower reaches of Kinnikinic Creek (0.15 miles) and seasonal passage for up to 8.3 miles providing cold water refugia and rearing habitat for steelhead, Chinook Salmon, and Sockeye Salmon. This barrier is the most expensive and technically challenging of the four barriers on the stream to replace, and once this barrier is replaced, partners will address the three upstream barriers ultimately providing full fish passage to 8.3 miles of Kinnikinic Creek for ESA listed salmonids and other fishes.