Barnaby Creek Recovers Spawning Ground
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- Published: Friday, 28 June 2013 18:45
It’s been over seventy years since Grand Coulee Dam forever altered native fish migrations. With the completion of the new Barnaby Creek Culvert, the Colville Tribe, with funding from the Bonneville Power Administration, have taken another step towards returning kokanee and rainbow trout to their historic spawning grounds.
Kokanee and rainbow trout make annual adfluvial migrations, meaning they travel from lakes up through rivers and streams in order to lay and seed eggs. Barnaby Creek was once such a tributary, but an inadequate culvert, created during the Grande Coulee Dam construction, made fish passage impossible.
The old culvert tunneled the creek under Inchelium Kettle Falls Road, where the water would then drop up to seventy feet before reaching the Columbia River. Needless to say, the jump proved too much for even the LeBron James of kokanee.
Replacing the drop with fish friendly access required complex engineering, skilled construction, and serious funding. The $1.5 million budget came from the capital portion of the Chief Joseph Kokanee Enhancement Project, a settlement funded by the Bonneville Power Administration.
To accommodate the drastic water level fluctuations created by the dam, the engineering company, Tetra Tech, designed two culverts at different heights. The lower multiplate culvert is 22 feet in diameter with an 8% grade, and the surface culvert is 12 feet in diameter with a 0% grade. Boulders were placed inside and around the culverts to provide fish a place to rest behind as they push their way against the current. Material was also filled in the bottom of the culverts to simulate a natural riverbed. Extensive cut-off walls were built around the creek to protect the banks from erosion. Ferry County Public Works Department removed 20,000 cubic feet of fill to make way for the new fish passage.
Construction proved difficult, as heavy rainfall turned the banks into a muddy, unstable, and potentially treacherous worksite for tractors. Furthermore, rising water levels from dam operations meant workers had about two months to finish the project before they would be underwater.
Said, Bret Nine, the Colville Tribe Resident Fish Program Manager, “The project was very stressful, but very rewarding.” Nine participated as the new culvert went from an idea in 2004, to a funding request in 2008, to a precarious construction site in April 2011. In June 2011, he saw its successful completion. The finished product came just in the nick of time, as rising waters threatened to submerge the work in progress. In hindsight Nine was able to smile about the close call, recounting how workers won the race against time.
Although it’s still too early for official data regarding the project’s success, early indications are positive. Before construction was even complete, Nine saw rainbow trout beginning to make their way upstream. To jump-start the kokanee migration the spawning ground will be seeded with 250,000 eggs. As the project moves forward, optimism is high.