Dry Creek Habitat Enhancement Project

cbec was contracted to assist in the design and creation of habitat enhancement features on Dry Creek below Warm Springs Dam in Sonoma County.

Working with Inter-Fluve, the project aimed to benefit rearing salmonids under an altered hydrologic regime. The Dry Creek Habitat Enhancement Project ultimately provided six miles of improved rearing habitat and is an important component of a larger effort to improve conditions and promote recovery of listed salmonid species in the Russian River Watershed. Specifically, cbec supported development of concept designs and performed detailed field surveys of the low flow channel.

cbec supported Inter-Fluve during preliminary design by attending a 3-day site reconnaissance and reviewing planning documents. The goal of the site reconnaissance was to visit potential project sites, ground truth concept designs, identify additional site constraints, and collaborate on the design concepts to be carried forward to 10% design. cbec observed site conditions, performed a detailed survey of the low flow channel for up to five sites totaling up to 1.25 miles to inform the surveying and 2D modeling tasks. A hydraulic analysis was performed with a two-dimensional (2D) model prepared for the reach of Dry Creek extending from several hundred feet below Warm Springs Dam at Bord Bridge to Lambert Bridge (approximately 6.8 miles). The 2D model was prepared using the GIS-based hydrodynamic software package TUFLOW, which solves the full set of shallow water equations. A total of 12 simulations were modeled based on 2 topographic conditions (i.e., existing and project) and 6 flow conditions (i.e., 110 cfs, 1-, 2-, 5-, 10-, and 100-year events). Multiple iterations for the project simulations were conducted as the design for each site was refined from 30% through 90%. This analysis was documented in a Basis of Design Report. cbec also provided review of construction documents and assisted with public stakeholder involvement.