Beaver Dam Inventory and Beaver Dam Capacity Estimates

Beavers and their dams can substantially change the storage and movement of water through a stream reach. The magnitude of this change is, in part, a function of the number and type of dams plus stream characteristics. If beaver activity is to be considered as a flow-management aid, then understanding the locations where beavers currently are building dams and the potential locations and number of dams that beavers could build in the future would help inform how managers approach the management of beaver activity and prioritize habitat restoration actions that may support dam building by beavers.

For this component of the Tualatin beaver study, USGS:

1. Created a partial inventory of beaver dams by conducting strategic beaver dam surveys and compiling existing dam observations from basin partners.
2. Estimated and validated potential beaver dam capacity in Tualatin River basin streams by modifying an existing beaver dam capacity model that accounts for physical controls on where beavers can build dams.