Bronson Creek Floodplain Enhancement

The installation of 350 units of large woody debris habitat sets the stage for floodplain enhancement and regeneration in a sensitive riparian corridor.

Bronson Creek is an urban stream in Washington County, Oregon. Its water ultimately flows to the Tualatin River, which supports salmonids and other species protected under the Endangered Species Act. Though Bronson Creek may have supported steelhead or other salmonid species historically, it has more recently exceeded standards for pollutants such as bacteria and high temperatures.

In a unique partnership to enhance Bronson Creek, Clean Water Services (CWS), a public utility, and the Tualatin Hills Parks and Recreation District (THPRD), a municipal agency, launched a floodplain revegetation project.

To begin the revegetation process, Biohabitats installed large woody debris (LWD) structures which not only add habitat complexity and improve water quality but also help reconnect the creek with its floodplain and distribute flood flows over the floodplain.

Challenges presented by the 10-acre, sensitive riparian corridor included its proximity to private homes and its heavily saturated soil. Biohabitats used low-ground pressure (LGP) equipment in conjunction with steel plates to gain access to each LWD complex area. The innovative construction access into saturated wetland soils also included seeding, mulching, and erosion control.

Biohabitats provided log jam installation, log placement, and vertical pile log installation in sensitive areas. More than 150 root wads and 250 vertical pin pile logs were installed among existing beaver dams within the floodplain. Once fully revegetated by CWS, the project will not only improve water quality, habitat, and floodplain connectivity, but it will help THPRD gain additional shade credits toward a National Pollutant Discharge Elimination System (NPDES) permit.