Wednesday November 1, 2023
PhysOrg —
Called by the sound of flowing water and ample trees, a family of beavers have moved into Carkeek Park, building a series of dams along the mouth of Pipers Creek.
The largest dam—which incorporates a fixed park bench and two large trees—has widened and grown to the degree that water is spilling on to a walking trail nearby. The dam, reinforced with mud and branches, also may present a challenge for chum salmon, which are set to return and spawn at any moment, said David Koon, the salmon program director at the Carkeek Watershed Community Action Project.
It’s not clear yet how the beaver dam will impact the spawn, he said, and some of that will depend on how much and when it will rain this season. Beavers build dams to create a pond where they can build a “lodge” to provide protection from predators.
In a natural environment—where a river flows consistently all the time—a beaver dam would be no problem for spawning salmon, he said. But Pipers Creek, surrounded by a highly urbanized and concrete-laden watershed, is no natural river.