Beavers return to Sonoma Creek

It’s been a long summer of extreme drought conditions in Sonoma Valley. But in what seems like a steady stream of dire news for the local watershed the Sonoma Ecology Center finds one glimmer of good news stands out: beavers are moving back into Sonoma Creek.

The SEC shares the story in its latest Ecology Blog.

The return of these charming dam builders isn’t quite breaking news – since 1993 beavers have slowly made a comeback in Sonoma Valley. But this year, in the middle of peak dry season, their increasing presence is something for celebration.

From the perspective of drought resiliency and water retention in our watershed we’re observing how beavers are a positive factor in keeping what water is in creek beds and reducing hydrological impacts of water rushing through the main stem of Sonoma Creek. Their natural impulse to build dams and create ponds is a major factor in retaining refuge habitat for species that rely on water to survive.

Beavers provide refuge habitat for crawdads, California roach, Sacramento suckers, frogs and the endangered California freshwater shrimp which rely on deep pools and submerged, structural habitat like fine tree roots which are often present in the structure of a beaver dam. Any animal, insect, or crustacean that requires water to live in our creek is something that benefits from the damming that the beavers do.

In the lower watershed of Sonoma Creek where sections are drying out, Sonoma Ecology Center observes the transformational effects that beaver dams have. Locations that would otherwise be completely dry have standing pools of water even now, prime examples of aquatic habitat retention by beaver activity.

There are some issues of note that can arise with the presence of beaver ponds. One such issue being a proliferation of water fern or duckweed growing over standing pools. However, it’s better to have water in the creeks than none at all, and these refuges of cold pools allow many species that can handle the duckweed a little extra room to survive a dire drought year.

In town, beavers can cause localized flooding and/or excessive soil wetness where development or agriculture have encroached upon low floodplains. All in all it’s a net positive to have beavers back in our Valley and making their mark on our watershed.