Bay Area's First Climate Adaptation Project Could Be a North Bay Highway

The 21-mile highway, known as SR 37, connects the counties of Marin, Sonoma, Solano, and Napa while skirting the San Pablo Bay. It suffers two unrelated problems: flooding caused by high tides and traffic congestion.

Fixing the highway's problems "to avoid its potential loss in the next 20 years because of flooding will be our first regional foray into adapting to sea level rise — an issue that will threaten most of our shoreline infrastructure, coastal ecosystems and population centers," write University of California at Davis ecologist, Fraser Shilling, co-director of the Road Ecology Center, and Steven Moore, a civil engineer and vice chair of the State Water Resources Control Board, in this cover story for the Insight section of Sunday's San Francisco Chronicle.

Today the highway is built atop a berm, an outdated method of building roads across marshes and waterways that constricts the ability of the bay to improve water quality by filtering out pollutants, produce more fish and wildlife, and absorb floods.

Currently, some are advocating for raising the highway [$1.3 billion] in its current location, with the primary goal of increasing traffic flows, at least in the short term. Although cheaper than the bridge-causeway alternative [$4 billion], the berm approach misses the more holistic opportunities of reconnecting marshlands to the bay and taking advantage of the flood-absorbing capacity of thousands of acres of these publicly owned wetlands.

One is reminded of the catastrophic damage done by Hurricane Harvey to Houston last month, caused in part by development choices made by the city and region. Mitigating flooding by connecting the marshes to the bay by either the causeway, which would still impact marshes, or what Shilling and Moore call the North Bay Bridge, may enable the project to tap the 2016 regional Measure AA funds for wetland restoration and adaptation to sea level rise.

Tolling an option

In 2015, the congestion management agencies of the four affected counties "agreed to form a partnership ...  to develop an expedited funding, financing and project implementation strategy for the reconstruction of SR 37 to withstand rising seas and storm surges while improving mobility and safety along the route," according to the Sonoma County Transportation Authority. 

A post last May indicated they are explore financing options which reportedly include the use of tolling and public-private partnerships.