Officials planning for extended Highway 37 closure after flood damage in North Bay

State transportation authorities were planning for what they called a possible “long-term closure” on Highway 37 southeast of Novato after floodwaters breached a levee in two spots near the roadway, inundating an adjacent pasture and undermining the parallel freight railway.

Westbound lanes of the highway were closed hours before the morning rush-hour drive Friday, stalling traffic for miles along a key North Bay commuter artery.

The closure could remain in place for at least another week.

A plan devised by a coalition of state and local agencies envisions reopening the westbound lanes no sooner than next Friday, said state Sen. Mike McGuire, D-Healdsburg. High tides expected in the coming days could force closure of the eastbound lanes as well.

“This is an all-hands-on-deck effort,” McGuire said. “The fix is complicated.”

The sheer volume of water, the area’s poor drainage and the extensive repairs needed to the busted levee made it difficult to give any clearer timeline, ?officials said.

“We’re at the mercy of Mother Nature at this point, and the broken levee,” said Caltrans spokesman Vince Jacala. “We can’t pump the water, because there’s nowhere to pump the water to.”

It’s the latest major transportation dilemma to hit the North Bay after the nine-hour closure last week of the Richmond-San Rafael Bridge because of falling concrete.

Highway 37 traverses 21 miles across the top of San Pablo Bay from Novato to Vallejo and sees as many as 45,000 vehicles per day. It is a critical route for commuter and weekend traffic and has a history of flooding problems, with no long-term fix in sight.

The cost of rebuilding the traffic-?clogged, low-lying roadway has been estimated at more than $3 billion, with construction not expected to start for at least another decade.

“We need to continue moving forward as quickly as possible on both a short-term fix to alleviate congestion and closures, but also a long-term fix of really making the road more resilient to high-water bay level rise,” said Sonoma County Supervisor David Rabbitt, who holds appointed posts overseeing regional transportation. “But it is of course a matter of dollars.”

The closure of westbound lanes followed breaches in a levee on the south side of Highway 37 as rain-swollen Novato Creek combined with tidewater rolling in from San Pablo Bay. Authorities were preparing for a closure Thursday night and instituted it at about 3 a.m. Friday for the westbound lanes, which are on the highway’s north side.

“It’s a pretty complex system and requires a delicate balance, especially when the tides come up,” said Rabbitt.

The floodwaters washed out railroad tracks running along the highway’s eastbound lanes. The rail right of way includes the damaged levee, which is owned by the Sonoma-Marin Area Rail Transit agency, according to McGuire. Presently, the rail traffic is limited to freight trains operated by the Northwestern Pacific Railroad.

CHP, Caltrans, rail officials, Marin County public works crews and transit leaders were studying the site Friday to devise the short-term fix. McGuire said it would involve placement of a temporary dam, beginning Saturday, construction of a haul road, draining of the 600-acre pasture now covered by “an enormous amount of water,” and repairs to the damaged levee.

A representative of NWP Co. said Friday that the repairs would cost hundreds of thousands of dollars. McGuire said it could be more. Marin County Public Works crews will oversee the dam work starting Saturday.

“This is not a quick fix, and something that has to be assessed by all agencies for the best course of action,” Julian Kaelon, a public works spokesman, said Friday afternoon. “It’s not a simple solution at all.”

The flooding marks the second time in two years that the troubled roadway has faced prolonged winter closure. In early 2017, a record level of rainfall flooded an adjacent 100-acre field and resulted in 27 days of full or partial closure.

The flooding highlights the need for a more immediate and aggressive investment in transportation infrastructure in the North Bay, McGuire said.

“We are seeing the results of under-investment in our infrastructure that has accumulated over the past several decades,” said McGuire. “And it’s simply unacceptable. Highway 37 is one of most susceptible state highways to sea level rise in the entire inventory of lane miles throughout California. That’s why we need a big picture fix.”

Studies have shown portions of the highway will be regularly flooded by 2050 and completely submerged by 2100. Long-term designs call for an elevated structure that could be operated like a toll bridge.

A ballot measure approved by Bay Area voters in June authorized $100 million from state bridge tolls to begin design and environmental review studies.

You can reach Staff Writer Kevin Fixler at 707-521-5336 or kevin.fixler@pressdemocrat.com. On Twitter @kfixler