Plans are moving forward for a solution to a flood-prone river crossing west of Santa Maria that serves as a key link between agricultural hubs in Santa Barbara and San Luis Obispo counties.

The federally funded Bonita School Road Bridge Replacement Project will replace the aging low-water crossing on Bonita School Road with a durable all-weather bridge designed to eliminate recurring closures.

A significant upgrade

The existing bridge over the Santa Maria River, built as a temporary solution in 2002, is frequently closed during heavy rains, disrupting the daily flow of more than 2,000 vehicles, according to Santa Barbara County officials.

The new 2,321-foot-long, full-span concrete girder bridge will be a significant upgrade, replacing a structure that spans just 300 feet of the river.

“I really think it’s going to be a tremendous improvement for circulation to the community,” said Esau Blanco, an engineering manager with Santa Barbara County Public Works, the agency leading the project.

The current crossing’s design is meant to breach during major floods, resulting in a cycle of costly repairs, according to project documents. 

Blanco called it “a maintenance nightmare,” noting that the crossing is not a paved road but is instead compacted dirt over the riverbed, which creates hazardous conditions even in smaller storms.

Compounding these issues, the bridge is also classified by Caltrans as “Structurally Deficient.” Routine inspections found stress cracks in critical elements, contributing to a sufficiency rating of just 48.3 out of 100, according to project documents.

“There’s extensive potholing and divots that people have to navigate around,” Blanco said, adding that the conditions significantly slow down traffic, particularly for loaded agricultural trucks.

The new bridge will sit up to 21 feet above the riverbed, ensuring it remains open during high-flow events. It will feature two 12-foot traffic lanes, 8-foot paved shoulders to accommodate bicycles, and a protected 5-foot pedestrian path.

Blanco noted that while the shoulders will improve safety for cyclists, they are paved shoulders and not officially designated bike lanes.

Community support

The project has garnered broad support, a sentiment expressed at a recent community meeting at Bonita Elementary School in Santa Maria.

“For the most part [it was] positive — very happy that the project is going to be moving forward soon,” Blanco said of the reaction. He said residents’ main questions focused on property access and traffic detours during construction.

That support is echoed by the region’s agricultural industry. Claire Wineman, president of the Grower-Shipper Association of Santa Barbara and San Luis Obispo Counties, said a dependable bridge provides a critical connection for employees, vehicles and equipment.

“We commend the county’s investment in infrastructure and the coordination on design to accommodate the uses and anticipated types of agricultural vehicles and equipment that might be utilizing the bridge,” Wineman said.

Construction and detours

Construction is expected to begin in 2026 or 2027, and Blanco said it will require a full closure of the roadway for the duration of the project, which is estimated to take two years.

Some residents had expressed concern about a simultaneous closure of the Highway 1 bridge. However, Blanco said the county has coordinated with Caltrans, and that Caltrans confirmed it will maintain access on Highway 1 throughout its separate construction project.

Funding and environmental hurdles

The project is 100% federally funded through the Federal Highway Administration’s Highway Bridge Program, Blanco said.

The timeline has been shaped by a complex environmental review and permitting process. Blanco said the project’s location had to account for impacts on species such as the California steelhead trout and red-legged frog. 

He said construction on the sensitive habitat required coordination with multiple state and federal agencies, including the U.S. Army Corps of Engineers and the California Department of Fish and Wildlife.

The final hurdles before construction can begin are completing the environmental permitting and the right-of-way acquisition process.

A detailed project overview provided by Santa Barbara County Public Works can be found here.