County public works explains the stump in Cascade Creek at Buck Bay bridge | Letter

Published 11:45 am Thursday, November 3, 2011

San Juan County Public Works provided this response to Tom Welch’s recent letter, “New Buck Bay bridge… or ‘Blockade Creek’?“

Dear Mr. Welch.

Thank you for the excellent question about the stumps Public Works placed in and adjacent to Cascade Creek upstream of the new Buck Bay bridge.

We posed the question to Brendan Brokes, our Area Habitat Biologist at the Washington Department of Fish and Wildlife, and this is how he responded:

“Numerous studies have shown that LWD (Large Woody Debris) is a vital and naturally occurring component of healthy stream ecosystems. Water flowing over and around LWD creates scour pools and helps sort and distribute sediments. Pools are deeper water habitats that provide critical hiding and resting areas for fish and are especially important during low stream flow. LWD also creates velocity shelters during high stream flows allowing fish to rest and expend less energy. LWD also traps and stores other large and small woody debris, leaf matter, spawner carcasses, and other organic materials that add to the complexity and diversity of instream habitats. LWD facilitates the transport of fine sediments where wood accumulation narrows a stream channel thereby increasing velocities and helping to maintain bed elevations.”

Thank you for your interest in this project.

Dan J. Vekved, P.E.

Civil Engineer 3

San Juan County Public Works