Shiloh Ranch Regional Park Riparian Restoration (Notification of Lake or Streambed Alteration, No. EPIMS-SON-43203-R3)

Shiloh Ranch Regional Park Riparian Restoration (Notification of Lake or Streambed Alteration, No. EPIMS-SON-43203-R3)

The California Department of Fish and Wildlife has executed Lake and Streambed Alteration Agreement EPIMS Notification No. EPIMS-SON-43203-R3, pursuant to Section 1602 of the Fish and Game Code to Sonoma County Regional Parks. The project is limited to restoration of the unnamed tributary and the associated on-stream pond. The project consists of three parts: eliminating the current pond spillway and replacing it with a rock-lined spillway and energy dissipation pools; filling in the eroded gully downstream of the pond and restoring the historic channel alignment; and filling and grading the upstream gullies as well as the sediment basin upstream of the pond. The lower reach and spillway portions of the project will stabilize the channel by rerouting the creek to mimic its historic alignment, then filling and restoring the gully created by the current spillway. The existing spillway will be demolished. In its place, a new, rock-lined spillway channel and energy dissipation pool will direct water from the pond to the winding footprint of the historic channel. Two rock grade control structures with energy dissipation pools at the original streambed’s downstream end will allow that footprint to be filled – thus creating a shallow meadow channel with a much gentler longitudinal profile slope of 1 percent. Fabric reinforced earth fill will be placed around the spillway, rock grade control structures, and tributary alignment. In the former gully, salvaged topsoil will be replaced, covered with an erosion control blanket, and seeded with native grass seed. Native upland trees and shrubs will be planted and mulched in the upland area. The floodplain and channel bottom will be planted with native wetland plant plugs. The upper reach portion of the project will fill in the sediment basin just upstream of the pond to a level grade. Wetland plant plugs will be planted to create a new, small wetland, rather than sediment basin, and reduce nonnative bullfrog (Lithobates catesbeianus) habitat. The upstream gully will also be filled in and graded with a biotechnical log grade control structure. This structure will consist of repeating clusters of logs, willow (Salix sp.) wattles and energy dissipation pools, with a 2 percent slope between each grouping. Wetland plant plugs will be installed on the gentle slope between each log structure. A small gully adjacent to the main channel and a small scour hole upstream will also be filled in. The project will result in temporary impacts of approximately 0.323 acres of riparian habitat and 1,000 linear feet of stream channel. All temporarily impacted areas will be restored with native plantings, seeding, and appropriate erosion control measures. No riparian trees will be removed as part of this project. Access and staging impacts are included in the impact total above, with the majority occurring within existing park roads and trails.

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San Francisco Bay Area

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