At times the water laps close to the edges of Highway 37 between Vallejo and Marin County -- and also very close to thousands of motorists who use it every day for work, commerce or fun.
Most of the heavily traveled two- to four-lane road between Interstate 80 and Highway 101, is only 1 to 2 feet above sea level. Caltrans says it has the lowest elevations of any Bay Area highway and some portions passing through marshes even dip well below that.
And that, plus worsening traffic congestion, are why state and environmental groups are so concerned that parts of Highway 37 could some day disappear under water due to such natural events as rising ocean levels and earthquakes.
"Rising sea level is a threat and that's what (the various
groups) are looking for -- how not to have everyone commuting by gondola," said Don Brubaker, San Pablo Bay National Wildlife Refuge manager.
Highway 37's complexities, plus what solutions might work, have been the subject of ongoing meetings, studies and debate by Caltrans and other agencies. The debate includes conflicting views on whether a danger really exists.
Just how quickly any segment of the 22-mile-long Highway 37 could flood over permanently is unclear.
Environmental and governmental experts say portions will be submerged in 50 years; others add that an earthquake could quicken that eventuality. Still others question whether the threat is serious at all.
Flooding between Vallejo and Novato
already happens when high tides occur during a heavy storm, Brubaker said. Those areas are at the Highway 121 intersection by Sears Point, and by the partial cloverleaf off Walnut Avenue in Mare Island.
Studying the problem
The University of California at Davis, Caltrans and a stakeholder group met more than a year studying Highway 37. They hoped to identify an ecological solution that balances commuter and efforts to restore Bay Area's dwindling marshes.
The group held seven unpublicized meetings -- in Sonoma, Marin, Napa and Solano counties. However, most public sentiment was secured through a survey sent to 500 area households.
Eliot Hurwitz of the Napa County Planning Transportation Agency said the meetings should continue, although any options will be expensive and have significant implications. But for Hurwitz's agency, keeping the corridor open is paramount.
"That really is the only connection between 80 and 101. If that gets closed, it pushes traffic (including heavy truck traffic) north and onto Highway 12, 121 and 116. That's totally unacceptable," Hurwitz said.
Currently, there's no money for Highway 37 and no immediate plans for roadwork or major projects, Caltrans Senior Project Planner Erik Alm said.
Nor is there funding for follow-up work on the stakeholder process, he said.
Despite the lack of money, various scenarios -- ranging from closure to an underground tunnel -- have been floated.
Highway 37 would need to be elevated six or seven feet to avoid sea level rising effects over a 75-year period, say Caltrans and other agencies.
One way to do that, deemed one of the more popular ideas, is to construct a causeway, although no funds for such an idea have been identified.
Caltrans hasn't let the lack of money stop it from forging ahead.
A large report prepared after the stakeholder meetings, plus other information, will go into planning for Highway 37's future, Alm said.
Eventually, Caltrans will complete its own report containing a vision and proposed future plans for the highway, he said.
State agencies, including Caltrans, are under a governor's 2008 executive order to consider the rising water levels in infrastructure planning.
"There is a growing regional awareness of the vulnerability of transportation projects" due to rising sea levels, Caltrans Senior Project Planner Erik Alm said.
Annual Golden Gate Bridge measurements indicate ocean levels have risen about 7 inches in the last 100 years. The National Oceanic Atmospheric Administration and other agencies predict the rate could intensify due to global warming.
Highway 37 must be saved
UC Davis researcher Fraser Shilling, who helped lead the year-long planning effort on Highway 37, as well as Caltrans's Alm, said abandoning the road is not realistic.
But Shilling said something must be done to prepare for flooding.
"It's not realistic to think that if we don't do anything with the physical layout, that Highway 37 is going to survive the next 50 to 75 years of sea level rise," Shilling said.
Meanwhile, some conservatives and a long-time Highway 37-commuter see such threats as exaggerated and an environmentalist diversion to claim more land to protect.
Large tracts on both sides of Highway 37, such as Sears Point and Skaggs Island, are already protected with efforts in place to restore them to marshes.
At Cullinan Ranch, the U.S. Fish and Wildlife Service is building a levee so the area can be flooded to create marshes.
Third generation Skaggs Island farmer Jim Haire scoffs at suggestions the roadway would ever be closed.
"I think it's just a joke. It's never going to happen," Haire said. "You are not going to get rid of Highway 37 traffic."
Political conservative Max Wessel of Vallejo, who attended one planning meeting as a member of the public, agrees the highway is a vital link that can't be abandoned. Further, he said he commuted the road for 23 years and believes it has a healthy mix of human and natural activities.
Options for Highway 37 on the table are unfeasible and so expensive they could result in another toll, Wessel said.
Though no solution or funding mechanism for the highway is on the table, finding money to pay for improvements came up frequently during the stakeholder meetings, Alm said.
Tolling and securing federal funds were mentioned as possible solutions as were banking on possible revenues from programs that don't yet exist, like money for sea level rise impacts funded by carbon trading, he said.
The next step
The first key step to any solution is getting an idea into a regional transportation plan so that it can be considered for funding.
The most recently adopted plan "Change In Motion" was adopted in 2009 and the next time is scheduled April 2013; and Highway 37 projects are not listed or nominated in either one, Alm said.
Though flooding threats are not immediate, Shilling said it may already be too late for proactive planning and construction.
"Time frame is everything in transportation planning. It's very likely that some of the first times Highway 37 is flooded will be before agencies have actually done anything," Shilling said.
Meanwhile, Haire said he doesn't expect the roadway to change much -- at least not in his lifetime.
"I'm 70 years old. When I go, Highway 37 is still going to be there and it should be," Haire said.
Contact staff writer Sarah Rohrs at firstname.lastname@example.org or (707) 553-6832. Follow her on Twitter @SarahVTH
©2012 Times-Herald (Vallejo, Calif.)
Visit Times-Herald (Vallejo, Calif.) at www.timesheraldonline.com