Swamp Creek Fish Passage Project (Siskiyou County, CA)

Swamp Creek is one of the few McCloud River redband trout streams north of Highway 89. Although this stream lacks connection to the McCloud, except in high flow events, it supports a good population of redband trout due to the cold perennial flows and relatively undisturbed morphology.

Two sites at culvert crossings have been identified as major fish passage barriers on Swamp Creek. The scour effects downstream of culvert crossings commonly create a vertical drop below the culvert that fish cannot jump at most flows. On many culverts, the water velocity inside the culvert adds an additional barrier to fish passage.

Both these problems are prevalent at the two culverts on Swamp Creek. To resolve this issue, StreamWise is working with the local timber landowner, Sierra Pacific Industries, CA Department of Fish and Game, and the US Fish and Wildlife Service to improve passage conditions.

The lower crossing passage improvement was designed and built in 2005. The design called for construction of downstream rock cross-vanes to raise the streambed elevation 4.5 feet below the culvert. This structure backs water into the culvert, allowing fish access. The CA Department of Fish and Game then installed a series of baffles to further improve passage conditions through the culvert.

This is a popular site for filling water trucks during logging operations. To minimize any impacts from such drafting, a passive intake hydrant was installed with a foot valve and screened intake. Drainage was redirected and mulched to prevent erosion.

The cross-vanes were constructed as a series of step pools that should allow easier fish passage after initial flows begin to “seal” the structures with fine sediments and gravel.

Work on the upper crossing site is scheduled for 2006.

Photo Gallery - click to open thumbnails
Swamp Creek pre-project condition. Severe scour below culvert. (2004)	Post project, with first cross-vane in foreground. (8/2005)
Post-project view from inside culvert looking into downstream pool. (8/2005)	Redband trout in pool below culvert. (8/2005)
Baffles installed by CA DFG. (Sept. 2005)