The project is limited to the removal and rerouting of a segment of one intermittent tributary and a segment of one ephemeral tributary to San Anselmo Creek, and installation of an energy dissipation structure at another intermittent tributary at the project site. This work is part of a larger project, with additional activities not covered under the Agreement, to construct two water storage tanks, each with a capacity for 2-million gallons, which will be partially buried into the hillside. A culvert upstream of the ephemeral tributary and a culvert and headwall downstream of where the two tributaries join will be removed. The flow from the intermittent tributary will be rerouted into a concrete channel and the flow from the ephemeral tributary will be rerouted via an 18-inch diameter pipe, with flows from both tributaries being released to where to the existing culvert and energy dissipation structure that outfalls further
downstream of where the two tributaries currently join. The existing culvert and dissipation structure will be refurbished or replaced, which will include placement of rock riprap (17.78 cubic yards). A security fence, along with emergency lighting, will be erected around the site. Each storage tank will also have emergency overflow piping connections that will reroute overflowing water through an 18-inch diameter pipe to a new 11-foot by 9-foot dissipation structure that will be located upslope of another intermittent tributary at the project site. Rock riprap (8.89 cubic yards) will be placed below the dissipation structure for erosion control. The project will result in permanent impacts to approximately 0.183 acres and 386 linear feet of stream and riparian habitat, and the removal of 23 trees. The project will not result in any temporary impacts to stream and riparian habitat.