The Big Importance of Small Woody Debris

Small woody debris is an important component in repairing riverine ecosystems. The main purpose of small woody debris on Redwood Creek is to give adequate space for small fish to remain undetected by aerial predators and provide cooler temperature waters away from direct sunlight.

Greater amounts of this space, also called interstitial space, have proven to support more dynamic and larger fish populations in other restoration sites. Fish are surprisingly not tolerant to wide fluctuations in water temperature and generally thrive in streams within a certain temperature range.

At Redwood Creek, because we have a brand-new creek channel with all the trees along the banks removed, small woody debris is a short-term answer until the willow and alder trees are able to mature.

Small woody debris is compiled from the branches and sticks removed during construction. Volunteers work with the Park Stewardship Marin team to assemble all the debris pieces and then lash them together. The bundles are then put into the water and anchored into place to prevent them from floating away.