Water Year 2021 Hydrologic Summary & Forecast: Mill Creek Watershed
In partnership with the Sonoma Resource Conservation District and Trout Unlimited, the Coast Range Watershed Institute completed a multi-year study of hydrologic conditions in the Mill Creek watershed with funding from the California Wildlife Conservation Board. A distributed hydrologic model was developed and used as a Decision Support Tool (DST) for evaluating flow enhancement strategies. This project is in its final stages as of May 2021 and a Technical Report documenting the project will be available later this year. The 2021 hydrologic forecast was prepared by O'Connor Environmental, Inc. for CRWI to provide timely information to land and water managers and residents regarding potential drought impacts. The forecast products compare Water Year 2021 conditions to the hydrologic model baseline period (2010-2019) in terms of precipitation, climatic water deficit, groundwater recharge, streamflow, and salmonid habitat. This work benefited greatly from hydrologic and fisheries monitoring data collected by Trout Unlimited and California Sea Grant.
Mark West Creek Flow Availability Analysis
In partnership with the Sonoma Resource Conservation District, Friends of Mark West Watershed, Pepperwood Foundation, and Sonoma County Regional Parks, the Coast Range Watershed Institute completed a comprehensive study of hydrologic conditions in the upper Mark West Creek watershed in December of 2020 with funding from the Califonia Wildlife Conservation Board. The project involved the development, calibration, and application of a detailed integrated hydrologic model to improve the understanding of streamflow and groundwater conditions throughout the watershed. Streamflow conditions were evaluated relative to requirements for salmonids and restoration prioritization maps were generated to help guide restoration planning efforts in the watershed. In addition to describing existing conditions, the model was applied as a Decision Support Tool to simulate future conditions resulting from climate change and provide a platform for testing and prioritizing strategies aimed at preserving or enhancing streamflow conditions.
An overview of the project and key findings is provided below in ArcGIS Story Map format along with a comprehensive Technical Report prepared for the project.
Stand Age & Forest Evapotranspiration: Implications for Forest Management, Streamflow, and Salmonid Recovery
Evapotranspiration from lower Russian River watersheds represents anywhere from 15 to 16 times the volume of all water used by humans on an annual basis. Given the level of regulation and investigation surrounding the relatively small anthropogenic water use component of the water balance, increasing our understanding and management of forest ET appears long overdue. This white paper, completed May 2021, describes the important role that forest evapotranspiration plays in the water balances of coastal salmonid streams and how improving our understanding of stand age composition and forest management effects may be critical for flow enhancement efforts to succeed. We explore forest evapotranspiration by summarizing the findings of recently published experimental watershed studies from northern California and Oregon, and perform a case study in the Mill Creek watershed to evaluate the sensitivity of streamflow and salmonid habitat to hypothetical reductions in forest ET.
This project, designed to identify and prioritize stream reaches for habitat enhancement projects within four tributaries of the Russian River (East Austin, Mill, Pena, and Redwood Creeks) was completed in June of 2018. The two-year project was conceived and executed by O'Connor Environmental, Inc. with assistance from its partner and fiscal sponsor, the Pepperwood Foundation. Funding was provided by the Fisheries Restoration Grant Program administered by the California Department of Fish and Wildlife. The project team developed a unique approach combining the use of high-resolution LiDAR topographic data to support hydrologic and hydraulic modeling of fish habitat suitability with existing habitat and monitoring data to efficiently evaluate more than 80 river miles of streams. The LiDAR data was obtained and made publicly-available by the Sonoma County Agricultural Preservation and Open Space District. Habitat and monitoring data along with technical input was provided by California SeaGrant and NOAA Fisheries. Work products include a series of detailed prioritization maps for each of the study watersheds which identify and prioritize reaches and sites for habitat enhancement projects.
A Technical Report and ArcGIS Story Map describing this project as well as other efforts completed by OEI can be found through the link below.
Lower Russian River Salmonid Rearing Habitat Delineation & Restoration Prioritization