Regional Water Quality Control Board, Region 1 (North Coast), Santa Rosa
Hillstone Farms Culvert Replacement Project
NOE - Notice of Exemption
The purpose of the project is to replace a failed existing culvert crossing and stabilize a streambank below an existing facility structure. Project would include removal and replacement of the failed culvert when the creek is dry. The new culvert will be sized to pass the 100-year flood and set just below grade to allow for native channel bed material to embed the culvert. The inlet and outlet will each have approx 15 lf of RSP placed for stability and interplanted with willows for channel bank stability and enhanced stream functions. Just downstream, approx 60 lf of failing RSP will be replaced with a bioengineered structure of RSP and willows to stabilize the banks protecting the existing structure.
The project involves annual replacement of an existing failed culvert and bank stabilization located at the site of the existing structures being restored and rehabilitated to meet current standards of public safety, with no expansion of use.