Large Woody Debris Replacement in Streams

LWD slide show

See slideshow of large woody debris replacement project.

Many streams in the watershed lack large woody debris as a result of past management practices. Large woody debris (LWD) replacement will help restore stream habitat while protecting existing structures and drinking water quality. By obstructing flows, LWD physically alters channel hydraulics, which influences sediment storage and transport. LWD often plays a major role in determining channel morphology.

In particular, LWD strongly controls habitat complexity, the frequency and characteristics of pools, bank stability, and the creation and maintenance of off-channel habitat. All of these features are important for salmon and trout, as well as many amphibian species.

Large Woody Debris Slide Show

See slideshow of Cabin Creek habitat enhancement project.

We have identified a subset of stream reaches in the watershed where LWD plays a critical role in forming pools and contributing to other key habitat elements. Factors such as bankfull widths, current condition of riparian stands, and range of in-stream LWD abundance strongly influence decisions about treatment strategy and relative priority. View a presentation summarizing several restoration projects on Rack Creek (pdf).

Where stands are dominated by young conifers or alders of insufficient size, active restoration of the riparian and/or in-stream wood placement are considered viable treatment options. Where in-stream habitat is found to be within the natural range of conditions for select indicators (e.g., pool frequency), LWD replacement is not needed but active riparian treatments intended to enhance the capacity for future recruitment of functional wood is considered.