Let’s talk about marsh, a type of wetland where the dominant plant species are herbaceous, like grasses and sedges, and water usually covers the ground. Marshes are biodiversity hotspots, but they also serve important ecological roles. Marshes slow storm surges and soil erosion, and, crucially, are a fantastic carbon sink. (Graphics: courtesy of Caltrans.)
Trees and forests capture carbon from our atmosphere, but seasalt wetlands sequester carbon ten times faster than tropical forest, according to the National Oceanic and Atmospheric Administration (NOAA). A damaged marsh cannot capture carbon at this rate, and can release its stored carbon into the atmosphere. Nor can a damaged wetland mitigate the effects of flooding as it should, providing a buffer between the ocean and our cities. A balanced marshland is a tremendous resource for us all.
We have a lot of marsh here in the North Bay, a good chunk of which is currently bisected by State Route 37, a perennially congested stretch of highway connecting Vallejo to Sonoma and Marin, the shortest route between one of the most expensive places to live in the U.S. and the much cheaper counties where many of its workers reside. This traffic is one issue of concern to residents, but another problem facing SR 37 is sea level rise.
NOAA and other nonpartisan scientific organizations predict sea level rise along the US coast of 10-12 inches over the next 30 years. That means that by 2050, damaging flooding will happen about 10 times more often than it does now. King tides will happen more frequently, and storm surges will get bigger. Marshland evolved to swell and retract with the tides as one of the first lines of defense against the erosive effects of water. SR 37 sits right on the edge of a marsh, nestled between the San Pablo Bay National Wildlife Refuge and the Napa-Sonoma Marshes Wildlife Area.
The California Department of Transportation (Caltrans) predicts that portions of SR 37 will be almost or completely underwater by 2050, if not before. It already floods frequently, since it rests lower than the surrounding levees. The cabinet-level California State Transportation Agency has partnered with several state agencies to consider how to protect SR 37 from the expected ravages of climate change, and ameliorate traffic conditions on the corridor.
Various county and regional transportation agencies have also formed groups over the last decade, such as Resilient SR37 and SR 37-Baylands Group, to weigh in on this issue. Baylands Group, which is led by the Coastal Conservancy, lists several accomplishments on their website, such as turning a mere transportation project into “the Resilient 37 Transportation Corridor Program that includes equity, ecology, and public access, as well as sea level rise adaptation.”
However, Caltrans recently decided to forgo a causeway that would lift the road out of the marsh, and instead wants to move forward with widening the road to add in high-occupancy lanes along with a toll. While a boost in federal funding was announced last month and it seems to be Caltrans’ intention to use it for elevating the road above Novato Creek, there is no indication that the rest of SR-37 will be similarly improved. As the population continues to grow, housing prices keep going up, and sea levels rise, this decision might end up costing us more money in the long run.
Actions You Can Take
Caltrans hosts periodic public meetings. You can view its Draft Environmental Document on the Caltrans website (https://dot.ca.gov/caltrans-near-me/district-4/d4-projects/d4-37-corridor-projects/37-meetings-events). Comments by mail or email may still be welcome.
Sierra Club Redwood Chapter is keeping a close eye on this project. Visit its website (https://www.sierraclub.org/redwood) for updates and position statements.
Representative Mike Thompson’s office recommends contacting your state senator and state assemblymember, as federal funds for infrastructure fall under the purview of the State Legislature.
Elayna Trucker is the lead buyer and operations manager for Napa Bookmine, a member of the Napa Sierra Club Executive Committee, volunteer social media coordinator with the Sierra Club Redwood Chapter, and a member of Napa Climate NOW! communications team (www.napaclimatenow.com).