The wolf restoration in Yellowstone has allowed the beavers to recover and they are creating ponds and such to the benefit of the fish and ecosystem.

In eastern Oregon they are trying artificial beaver dams (in hopes of helping the beavers) in some smaller streams. With the beavers and their dams the streams don't downcut as much, sediment is retained, riparian shade returns and the water table in the surrounding floodplain rises which the sub irrigates the pastures.