Marin City Second Culvert Project

Project Overview

Detail of the Project area over an aerial map. The Project area overlaps US 101 and the US 101/Donahue Street interchange, and is directly west of Richardson Bay.

Flooding affects the entire California Highway System, and Caltrans is looking for ways to mitigate the issue, especially with sea-level rise expected to affect the region in the next 100 years.

With the Second Culvert Project on US-101 in Marin County, Caltrans proposes to build a 6-by-4 culvert that will help mitigate flooding in the Marin City area. The location is near Marin City from Donahue Street to 0.3 miles north of Donahue Street.

The Draft Environmental Document (DED) for this project is scheduled to be circulated externally in June, 2025.

Environmental Documents

Caltrans Informational meeting

Caltrans will host a hybrid (in-person and virtually via Zoom) public meeting on Wednesday, June 18 from 6 to 7:30 p.m. (doors will open at 5:30 p.m.) at the Marin City Senior Center, 640 Drake Ave, Marin City, CA. 94965.

At this meeting, attendees will have the opportunity to learn about the project and ask questions. Join us in person, or go to CaltransD4Environmental.com for information on how to join virtually.

Hybrid (In-Person and Virtual) Public Meeting
June 18th, 2025, from 6:00PM to 7:30PM

In-Person Meeting: Doors will open at 5:30PM for an in-person open house, followed by a presentation at 6:00PM.
Marin City Senior Center
640 Drake Avenue
Marin City, CA 94965
Virtual Meeting Link: https://us06web.zoom.us/j/85874564998 Or by phone: (669) 900-6833
Webinar ID: 858 7456 4998

Meeting Materials

Submit a comment in writing during the public comment period, from Wednesday, June 4 to Monday, July 7, 2025.

Send by mail to:
Caltrans District 4, Office of Environmental Analysis
ATTN: Christopher Pincetich,
P.O. Box 23660, MS 8B
Oakland, CA 94623-0660

Or by email to:

Project Schedule

The project is scheduled to go into construction in 2027.

Caltrans is coordinating with Marin County and the Marin City Stormwater Task Force, which includes a county project, permanent pump station and floodwall within project limits. These Marin County projects are not part of this project. Please contact the county for more information.

Please send questions to marin_city_second_culvert_project@dot.ca.gov