Fanno/Ball Creek Restoration

Project Description

Fanno Creek, a heavily urbanized tributary of Oregon’s Tualatin River, has been impacted by floodplain development and urban runoff. This is particularly true at the Creek’s confluence with Ball Creek, where severe incision has threatened infrastructure and resulted in actively eroding vertical banks as high as 15 feet.

With a conceptual restoration design in hand, Clean Water Services (CWS) turned to Biohabitats for help with refining and executing the design, and working with land owners adjacent to the site to coordinate construction access.  With the goals of stabilizing banks, improving floodplain connectivity, and enhancing instream aquatic habitat, Biohabitats began by assisting CWS in assessing the site and adapting the conceptual design to the rapidly changing channel conditions. Biohabitats then prepared construction cost estimates. Before implementing the design, Biohabitats diverted and dewatered the stream and salvaged fish.

Biohabitats then led excavation, log jam installation, and bioengineered bank construction. Over 300 liner feet of bioengineered bank stabilization matrix was installed. This involved the strategic placement of more than 50 rootwads, 100 logs, and 300 feet of coir fabric encapsulated soil lifts with brush layering. Toe logs and rootwads were installed below the base flow discharge elevation of Fanno Creek to ensure the long term preservation of the wood.  Throughout the project, Biohabitats worked closely with the CWS watershed team and landowners to ensure the project yielded minimal disturbance and maximum success.