Staff from the Environmental Services' Willamette Watershed team shared some photos of recent work by a busy beaver in the Stephens Creek subwatershed. This is at the site of a 2008 sewer repair and stream enhancement project, just off SW Taylors Ferry Road. Stephens Creek is one of the only remaining free-flowing streams in Southwest Portland to the Willamette River. Many other streams have been piped underground to allow for development over the course of Portland's history. Continued protection, restoration and enhancement of Stephens Creek is important to improve water quality and habitat, and to protect other infrastructure like sewer pipes and roads.
The beaver had just felled this large tree over the creek, and was at work on a second one. Typically, trees and other large wood that fall naturally in and near streams is a good thing, creating habitat and shaded, cool water for native fish and other critters. Many urban streams and rivers lack large wood because development has cleared out trees that would have otherwise grown, died, and fallen naturally. In some stream restoration projects, like the recent Columbia Slough Confluence project, and at the confluence of Stephens Creek with the Willamette River, Environmental Services intentionally places large wood to re-create these natural conditions.
On this site in Stephens Creek, the second tree that the beaver was working on posed a potential safety risk to a nearby parking lot, so staff fenced the tree's base to prevent the beaver from finishing his job.
For more information on the Willamette River watershed and the Stephens Creek subwatershed, go here. Can you tell the difference between a beaver (native to Oregon!) and a nutria (invasive species!)? Find resources on this Science, Fish and Wildlife program page.