Beaver Dam Analogs — Good for Streams and Fish

Submitted by Mid-Columbia Fisheries Enhancement Group

This week we have been installing Beaver Dam Analogs (BDAs) in a side channel to Rattlesnake Creek in an effort to improve rearing habitat for juvenile salmon, steelhead, and bull trout.

Like natural beaver dams, BDAs slow down and spread out water which forces it laterally into the substrate. This encourages riparian plants to grow, increases groundwater storage, and moderates stream temperatures. Beaver are active in the area and creating favorable habitat in the side channel will hopefully lead to their long term occupancy and maintenance of this project.

All of these activities will improve rearing conditions for juvenile salmonids in an area where side channel habitat is limited. A special thanks to our grant funders DOE and USFWS!

A hydraulic post pounder is used to drive 6 ft untreated pine post in to the substrate. These posts help hold the BDA in place during high flows and provide structure for weaving plant materials

Wood chips (the debris floating on the surface) are added to the BDAs to improve the seal and back up water. No amount of wood chips could completely seal the dam. Juvenile fish can easily find gaps to get through these dams.

Looking upstream: this completed BDA has already raised the waterlevel a few feet on the upstream side and forced water laterally which has provided water to 100 yards of a previously dry secondary channel.

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