Green Valley Creek is a large tributary to the Russian River, with a drainage area of approximately 31 square miles above the project site. The Iron Horse Vineyards property is one of the largest single-owner properties on lower Green Valley Creek in west Sonoma County, and has provided a unique opportunity to create large, flooded off-channel areas for salmonids. The Iron Horse Vineyards Off-Channel Habitat Enhancement Project was developed by Gold Ridge Resource Conservation District and Prunuske Chatham, Inc. to evaluate site conditions and design habitat enhancements along the stream corridor. Funding for the project came from Prop 1 through the California State Coastal Conservancy and the California Department of Fish and Wildlife (CDFW). The project was supported by multiple resource agencies through a Technical Working Group that included CDFW, NOAA Fisheries, and the North Coast Regional Water Quality Control Board, along with the landowner.
The overall objectives of the project are to provide complex, low-velocity in-channel and off-channel habitats to support juvenile salmon during their winter rearing and spring outmigration lifestages, contributing to the recovery of coho populations in Green Valley Creek and the Russian River. PCI developed an integrated site design to significantly increase off-channel rearing and refugia habitat. Several additional objectives informed the site evaluation and preliminary design, including the desire to: maintain balance between coho habitat needs and other critical floodplain functions (groundwater recharge) and habitats (shallow seasonal ponds used by amphibians), provide habitat for other special-status species, maintain or increase wetland area within the project footprint, and increase wetland habitat diversity. PCI also prepared 2D hydraulic modeling and 100% plans and specifications, completed Winter 2019.