Habitat Enhancement Monitoring

Mill Creek Dam Fish Passage Project

Mill Creek is a major tributary to the Russian River that harbors some of the best habitat for endangered coho salmon and threatened steelhead trout within the watershed. For many decades, migratory fish access to Mill Creek and its tributaries was severely impeded by a large flashboard dam that blocked passage to approximately 11.2 miles of stream. Moreover, the portions of Mill Creek above the dam site offer some of the best rearing habitat in the Russian River watershed and consistently remain wet, whereas much of the reach below the dam goes dry during the summer months. This dam was identified by NOAA Fisheries as “the highest priority barrier within the Russian River [coho] population for remediation.” 

In October 2016, Trout Unlimited and Prunuske Chatham, Inc. completed a project to restore passage over and around the dam through construction of a roughened ramp and low-gradient side channel. Located, literally, in the backyard of several residential properties—and with many site constraints—this project required years of careful planning and negotiations. The project photo documentary illustrates each step in the construction process. The project was implemented with funding from the NOAA Restoration Center’s Community-based Restoration Program, the CA Department of Fish and Wildlife’s Fisheries Restoration Grant Program and the Sonoma County Water Agency, and would not have been possible without the support and cooperation of neighboring landowners. CA Sea Grant's Russian River Salmon and Steelhead Monitoring Program, who are responsible for pre- and post-project monitoring, are excited to report that numerous coho salmon were observed spawning upstream of the former dam site within weeks of project completion. 

The Mill Creek dam before project implementation, looking upstream
MaryAnn King (TU) and Joe Pecharich (NOAA) stand upstream of the newly-modified dam site on Mill Creek
Mike Jensen (PCI) assesses winter flow through the former barrier site on Mill Creek

Green Valley Creek Winter Refugia Enhancement Project 

During winter storm events, juvenile coho salmon and other fish need shelter to protect them from high flows. Historically, large woody debris and inundated floodplains provided refuge but, throughout the Russian River watershed, much of the large wood has been removed from the channel over several decades and channelization and incision has caused some streams to be cut-off from their historic floodplains. In an effort to address this concern, the Gold Ridge RCDNOAA FisheriesCDFWSonoma County Water AgencyCalifornia Coastal Conservancy, and local landowners partnered to implement a winter refugia, off-channel enhancement project on Green Valley Creek.

In the fall of 2014, a seasonally-flooded side channel was constructed adjacent to the main stream and several large wood structures were installed to add complexity and shelter. CA Sea Grant's Russian River Salmon and Steelhead Monitoring Program used PIT-tag technology to evaluate fish use of the project reach before and after project implementation, in order to document the effectiveness of the enhancement project in providing seasonal refuge for juvenile coho salmon. A full discussion of monitoring methods and outcomes can be found in the Green Valley Creek Winter Refugia Enhancement Project Monitoring Final Report.

PIT tag antennas are used to track salmon moving past the inlet and outlet of the side channel refugia
Green Valley Creek off-channel habitat when active at high winter flows