Fisher’s Bend Side Channel Habitat Design, Clackamas River

Alcove

HENDERSON is working with multiple stakeholders, including private property owners, Clackamas County, the Clackamas County Soil and Water Conservation District, the Oregon Department of Fish and Wildlife, the US Fish and Wildlife Service, and the Oregon Wildlife Heritage Foundation in assessing, designing, and permitting restoration opportunities on Fisherman’s Bend, a unique 52-acre site in the Clackamas River.

The Clackamas Watershed encompasses 941 square miles and enters the Willamette River below Willamette Falls. The watershed supports naturally spawning anadromous fish including salmon, sea-run cutthroat trout, and Pacific lamprey. The river is home to ESA-listed lower Columbia River Coho and the lower Columbia River Steelhead and Chinook. Past development along the lower Clackamas River has reduced the amount of off-channel rearing habitat available to juvenile salmonids. The Lower Columbia River Salmon Recovery Plan lists the lower Clackamas River as a high priority for salmon recovery, and the Clackamas Basin Watershed Assessment and Action Plan identifies main stem side channel habitat as the most significant limiting factor for salmon production in the Clackamas Basin.

Fisher’s Bend consists of a private parcel known as Chrysalis Farms and 20-acres owned and managed by Clackamas County Parks. The site includes a degraded side channel, four groundwater and surface-water-fed ponds, remnant wetlands, a perched former side-channel and a currently channelized stream set in a mature ash-cottonwood, cedar and Douglas fir forest. This potentially productive and abundant habitat is currently isolated from the main stem of the river except at very high flows. Salmonids may become stranded during these events. HENDERSON’s primary design goal is to reconnect the Clackamas River to this riparian floodplain at lower flows and provide refuge and off-channel rearing habitat for threatened juvenile salmonids at critical stages in their life cycle. Project opportunities include enhancement of existing fish and wildlife habitat, improving water quality and restoring ecological functions and processes for the floodplain, streams, and wetlands of the site.

HENDERSON professionals have worked with project stakeholders to assess hydraulic condition of the site and to determine the optimum design alternative that restores fisheries function to the partially isolated floodplain and off-channel refugia. Our team then converted that optimal alternative into a stabilized restoration design. Under a design-build contract with the Clackamas River Basin Council, and with continued support and guidance from the Oregon Department of Fish and Wildlife, HENDERSON expects to implement the Phase I design during the summer of 2015.

Website Design by BOING