Scappoose Creek Salmonid Habitat Enhancement and Embankment Stabilization

As a tributary to the lower Columbia River, Scappoose Creek represents vital salmonid habitat which has undergone severe erosion and channel migration leading to loss of in-stream and riparian habitat as well as floodplain connectivity.  Working with the South Scappoose Bay Watershed Council, HENDERSON environmental design-build professionals implemented enhancements to instream and wetland habitat by laying back vertical, eroding streambanks, constructing in-channel floodplains, installing large wood habitat structures, enhancement of off-channel wetlands, and restoring the riparian corridor.  Scappoose Creek’s historic high flow channel was enhanced with logs and rootwads (LWD) and re-connected to the base-flow stream channel to provide greater frequency of high flow access to the historic floodplain.  Installed LWD also serve to increase habitat function of the enhanced stream reach by providing escape cover for adult and juvenile salmonids.  Embankment stabilization was achieved by HENDERSON field ecologists integrating the LWD material into vegetated encapsulated soil lifts constructed at a minimum 4:1 repose.  Scappoose Creek enhanced habitat function includes restored channel roughness, increased in-water habitat diversity, more-frequent access to the historic floodplain, and enhanced off-channel floodplain refuge for salmonids and other aquatic species.  Post-construction restoration success is evidenced by gravel deposition in the riffles, deepening and expansion of existing pool habitat, and increase in cover habitat within and adjacent to the large wood structures, and an increase in the hydroperiod of the expanded wetland.

Scappoose Creek Salmonid Habitat Enhancement and Embankment Stabilization

Website Design by BOING