Sea-level rise: a road runs through it

Scientists look at ways to deal with significant flooding of China Camp’s only access road.

To anyone who has visited China Camp during our annual “king tides,” it’s no secret that rising bay waters during these extreme tidal events quickly submerge North San Pedro Road. Big winter rains can compound the problem, flooding portions of the route, which provides the only vehicle access in and out of the park. Sea-level rise due to climate change threatens to make the problem even worse.

Protecting China Camp’s intact watersheds, with water flowing from San Pedro Ridge down to the bay, is an important part of future planning.

North San Pedro Road poses additional challenges. At present, it bisects the largest historic expanse of undisturbed wetland in the San Francisco Bay Region. The area is a rare example of a relatively undeveloped, largely intact watershed, protecting creeks draining from the San Pedro Ridge all the way down to San Pablo Bay. This protected habitat is home to several endangered species, including the Ridgway’s rail (Rallus obsoletus) and the salt marsh harvest mouse (Reithrodontomys raviventris). Proposals to reduce road flooding must also look at ways to protect this critically important habitat.

Pink segments of N. San Pedro Rd. are currently experiencing flooding during extreme tides.

Fortunately, research on how to deal with these challenges has begun. Working with California State Parks and other key stakeholders, the San Francisco Bay National Estuarine Research Reserve (SF Bay NERR) is studying the area’s hydrology and cultural resources, using this information to help identify the most feasible options for road reconfiguration.

To come up with answers, SF Bay NERR has been collaborating with these stakeholders to develop a suite of approaches to the problem: 1) raise the road above the level of floodwaters, with multiple configurations of how to do so, 2) reroute the road, or 3) take no action. Partnering with the County of Marin’s Department of Public Works, which technically owns North San Pedro Road, SF Bay NERR aims to begin additional engineering and design work. A final proposal should be ready by Fall 2023. 

Friends of China Camp has been an actively engaged partner since the project’s inception, and SF Bay NERR is very thankful for FOCC’s support. 

Learn more about the project and its importance in the face of climate change and habitat protection during our annual king tide walks this winter (check FOCC’s January 2023 events calendar). You’ll also find information at the project website. And you can join SF Bay NERR’s mailing list to receive updates on this and other important projects around the region. We welcome your interest.—by Aimee Good and Bella Mayorga, SF Bay NERR

Top PHoto: Harriot Manley. Insert photos courtesy of SF Bay NERR.