Hafner Vineyards Sausal Creek Streambank Repair
Stabilize an eroding streambank to retain safe vineyard operations, ensure natural habitat and species protection, and enhance critical habitat for steelhead.
WRA was retained by Munselle Civil Engineering to support a steambank stabilization along Sausal Creek in Sonoma County on the Hafner Vineyards property, a small family winery in Alexander Valley near Healdsburg in Sonoma County. The family property is over 250 acres with 100 used for growing grapes and producing wine with the remainder used for grazing. The project repaired a portion of the northwest bank of Sausal Creek, which had been eroding and sliding into the creek, causing loss of soil and trees over time.
Identified and minimized impacts to special-status species while supporting bio-engineering solutions to maximize ecological uplift.
WRA conducted baseline biological studies including an aquatic resources inventory, biological resources assessment, and biological assessment. These studies supported permit applications with the resource agencies including the U.S. Army Corps of Engineers, U.S. Fish and Wildlife Service, National Marine Fisheries Service (NMFS), California Department of Fish and Wildlife (CFDW), and Regional Water Quality Control Board. The project also required consultation with NMFS due to Sausal Creek’s designation of critical habitat for federal endangered Central California Coast steelhead (Oncorhynchus mykiss).
WRA supported Munselle with engineering of the streambank repair including the preparation of a HEC-RAS model to calculate water surface elevations, flow depth, and depth-averaged velocity and shear stress in the vicinity of the bank erosion area through the range of storm events. Based on the model results, WRA’s engineer recommended bank stabilization measures to prevent future erosion and enhance critical habitat for steelhead.
Before construction, WRA worked with the project team and relevant regulatory agencies to develop suitable measures to avoid impacts to sensitive species. Before construction, a WRA biologist conducted pre-construction surveys for nesting birds and CDFW Species of Concern, including Foothill yellow-legged frog, which was detected during the environmental review phase of the project. WRA staff prepared a Worker Environmental Awareness Program (WEAP) as required by the Project’s Stream Alteration Agreement and performed on-site permit compliance monitoring during construction.
Species and habitat disturbances were minimized and repair efforts ensured operations could resume and further damage would be prevented.
WRA’s work ensured that during construction, disturbance was minimized at the site, impacts to water quality was avoided, riparian areas were protected, and effects to sensitive species were minimized. Stabilization of the bank will prevent further erosion, and allow for continued safe operation of the adjacent road as well as enhance the critical habitat for steelhead.
Andrew Smith, PE
Senior Restoration Engineer
Regulatory Permitting Support
Streambank Repair Design Support
Worker Environmental Awareness Program
Environmental Compliance Monitoring