Cost of Sonoma County's seasonal bridges going up, expediting need for permanent solution

Faced with climbing costs from rising river flows, the county’s public works department has plans to make a century-old, bridge maintenance program ancient history.

Crews spent this past Thursday using a large crane to remove a 100-foot temporary span for vehicles across the Russian River at Asti to ensure it doesn’t wash away during winter storms. With wet weather already bearing down, the work represented the last of a few similar jobs around the county to prevent the bridges and related concrete blocks from being taken out by heavy flows and washing down river, potentially damaging other infrastructure.

“We’re having a race with time now to get that bridge out of the river,” said Johannes Hoervertsz, director the Sonoma County Transportation and Public Works Department. “These are the last three (bridges) in the county, and this one is the most complex and costly. We’re trying to figure out what to do in the future and are meeting with the community to come up with a long-term plan.”

The biannual tradition of installing the bridge just south of Cloverdale at Asti, and two near Guerneville at Odd Fellows Road and Vacation Beach Road, by Memorial Day weekend and later decommissioning them before winter, comes at a price. To provide seasonal access during the past 100 years across the Russian River for more convenient recreation - and increasingly as an evacuation road during wildfire season - the expenditure is one the county has been willing to cover.

Over the decades, however, costs have soared for the last remnants of an antiquated process.

Three years ago, the county paid about $273,000 to complete the work, including more than $158,000 for just the Asti crossing, according to county data. This past year, it rose to almost $442,000, including more than $280,000 for the Asti bridge alone in part because the area suffered erosion from the major flooding in spring 2019, which forced crews to add a second 100-foot seasonal span.

The county roads department estimates that reinstalling the Asti crossing will reach $625,000 next summer, a price tag that includes a new, 150-foot bridge because of erosion on the embankments, and $425,000 each year after that. With costs expected to continue their upward trajectory, officials may weigh a different approach.

“It sort of feels like wasted money,” Supervisor Lynda Hopkins said. “I guess it’s a similar parallel to rent or paying a mortgage, and can we shift our rent payments to mortgage payments for a permanent solution?”

For the past year and a half, the public works department has worked with a citizen group in Alexander Valley to consider such a plan. The community group funded a study showing the price tag for a fixed structure at Asti reaching as high as $20 million.

After removal of the Asti crossing last week, Hoervertsz will ask the Board of Supervisors on Tuesday to weigh in on how he should proceed in the years to come.

The department has offered to end the seasonal crossing program altogether, maintain the status quo at the higher cost and possibly after developing a bridge taxing district, or work toward a more permanent route.

Hopkins, whose district includes the temporary spans at Odd Fellows and Vacation Beach that have also gone up in price, said addressing each of the three bridges will ultimately be necessary.

Due to the erosion issues at Asti, though, and its importance based on a cost-benefit analysis conducted by the public works department, that location is the top priority.

Whatever the solution, she said, it will also require working with the state, which may be able to offer some funding, and other agencies because of stringent endangered-species protections over the Russian River.

But simply ignoring the seasonal issue won’t be an option, particularly as the region’s fire and flood seasons continue to converge, with the crossings becoming that much more important depending on the time of year.

“It feels like right now in Sonoma County we have two seasons, and there are impacts from both seasons on the safety of the other season,” said Hopkins. “So we need to shore up our infrastructure … whether it’s roads that slip out or whether it’s those bridges. They are a critical link.”

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