Cardinal Road Levee Upgrade Project

The Coyote Creek levee system was constructed by the U.S. Army Corps of Engineers in the mid-1960s for the purpose of protecting a portion of the Tamalpais Valley community from high flows in Coyote Creek and Nyhan Creek as well as from high tides from Richardson Bay. After the system was constructed, ownership was transferred to the Marin County Flood Control and Water Conservation District, which has been responsible for operation and maintenance of the system ever since. The purpose of the proposed Project is to address chronic seepage issues and flood risk associated with Coyote Creek and tidal backwater from Richardson Bay, which will provide long-term adaptation capacity for projected mid-century sea level rise. The 5.9-acre Project site includes a portion of Coyote Creek and surrounding tidal marsh habitat; ornamental, native, and ruderal vegetation; and developed areas. The Project includes installing a sheet pile floodwall along a 1,100-foot segment of the existing Cardinal Road levee, improving a maintenance path adjacent to the levee, installing a new storm drain system to convey stormwater flows, removing two concrete drain boxes and culverts along the levee, and replacing an existing culvert with a new culvert that will include a pipe seal to prevent leakage through the floodwall.