Lower Gales Creek Enhancement Planning Geomorphic Assessment Technical Study

In March of 2003 the Tualatin River Watershed Council completed work on the Lower Gales Creek Habitat Enhancement Plan (LGCHEP). The purpose of the LGCHEP was to outline an anadromous fish habitat enhancement strategy for a four mile section of Gales Creek that was identified as a priority restoration area through the Gales Creek Watershed Assessment Project (Bruener, 1998). 

From this process, the LGCHEP identified nine potential restoration projects designed to improve habitat conditions for steelhead (Oncorhynchus mykiss) and other salmonids. The nine projects included diverse habitat enhancement measures such as widening riparian buffers, increasing channel complexity by installing engineered log jams, and enhancing floodplain and secondary channel dynamics.

To move these projects forward to the design, permitting, and implementation phase, the Bureau of Reclamation has requested that a geomorphic analysis be conducted on the study reach to evaluate the following issues: 

• How is the channel functioning geomorphically as compared to historic conditions?

• What is the expected long term stability of the channel?

• Are the recommended projects appropriate within the existing morphology and sediment transport regime?

• What effects would the proposed projects have on planform and profile stability and sediment transport conditions?

• Are there external factors, such as land-use change or changes in downstream base level that would affect the future success of the proposed enhancement activities?

The technical study seeks to answer these questions.