Petaluma project team outlines $97 million Caulfield Lane movable bridge and extension

Petaluma officials and consultants presented an update on the Caulfield Lane drawbridge and associated Caulfield extension on Feb. 23, detailing design work, environmental steps and preliminary costs.

Bjorn Greetenberg, project manager for the design team, said the project would construct a movable (draw) bridge across the Petaluma River with two vehicular lanes, multiuse paths on each side and a counterweight housed below roadway grade to reduce visual impacts. "We've completed preliminary design, topographic surveys and a hydraulic analysis," Greetenberg said, adding that a final river boring is scheduled for this summer.

Jason Hickey, structures lead, described navigational clearances and coordination needs with federal and state agencies. He said the project includes about a 90-foot-plus horizontal opening and about 70 feet of vertical clearance above flood elevation for masted boats where required by the U.S. Coast Guard. "Coordination with the Coast Guard is important and critical," Hickey said, noting a notice to mariners would be circulated to solicit feedback on navigation clearances.

Consultants said the team reviewed alternatives and selected a pit-located counterweight to reduce the bridge profile compared with an overhead counterweight. "We moved the counterweight below roadway level into a pit pier," Greetenberg said. The change aims to limit visual impacts for nearby residences while maintaining navigational openings.

On costs, the team offered a high-level estimate: roughly $90 million for the movable structure and mechanical systems (including 20% contingency and escalation), $3 million for approach spans and about $4 million for the roadway extension — about $97 million in total. The presenter said the project is partially, but not fully, funded for construction and that staff will pursue additional funding. "The structure and mechanical equipment associated with the movable span is estimated at $90,000,000," one consultant said.

Council members pressed the team on operational and tradeoff questions: how often lifts would be required relative to the D Street Bridge, clearance at high tide (about 8 feet between water and the bottom of the bridge at normal high tide), and whether a fixed (nonmovable) bridge had been costed. Zach Sevilia, a project manager on the team, said a fixed bridge had not been costed because the river is a navigable waterway and Coast Guard permits for a low fixed-span bridge may not be available; he said a fixed structure would likely be significantly less expensive but could foreclose upstream navigation.

Several public commenters asked for landscaping, a riverwalk and attention to stormwater filtration; staff said bioswales and stormwater filtration exist in parts of the neighborhood and that the team will include landscaping in future designs. The timeline presented by the team calls for draft environmental documents later in the fall, final environmental work into 2027, design completion the following summer and a shovel-ready project looking toward 2028. The team also noted that full construction funding remains to be identified.

Next steps: the consultants expect another round of public engagement this spring and will post the Coast Guard's notice to mariners on the city's project web page when available. The city will return to the council with further analyses, design refinements and funding options as the environmental review and permitting advance.

(Reporting note: quotes and attributions are taken from council meeting remarks and the project presentation.)