Marin City Second Culvert Project

The Marin City Second Culvert Project, managed by Caltrans District 4 in the Bay Area/Oakland region, involves the construction of a new drainage system to convey stormwater flows from west of US 101 to Richardson Bay in Marin City. The scope of work includes replacing damaged storm drain pipes within the US 101/Donahue Street interchange area and repairing uneven pavement on US 101. The specific project area is located on US 101 from Post Mile 3.3 to 3.7 and on Donahue Street adjacent to the southbound on- and off-ramps in Sausalito, California. The project has undergone environmental review under the California Environmental Quality Act, resulting in a Mitigated Negative Declaration and a corresponding monitoring plan to ensure no significant environmental effects occur. Administrative approvals were finalized between August and October 2025, with the California Transportation Commission providing project approval. The project is identified by State Clearinghouse Number 2025060164 and is categorized under NAICS code 237310. Primary coordination is handled by Branch Chief Christopher Pincetich at the Caltrans District 4 office in Oakland.