Islais Creek Bridge to be Replaced

At 75 years old, the Islais Creek Bridge is overdue to be replaced. Located on Third Street between Cargo Way and Marin Street, the link connects the Dogpatch and Bayview neighborhoods. It was constructed in 1949 to enable trucks, pedestrians, bicycles, and freight trains to travel between San Francisco Port’s north and south terminals. The bridge is deteriorating and seismically vulnerable, according to San Francisco Public Works (SFPW), but still safe to drive across. 

In 2004, the California Department of Transportation reported that the drawbridge structure was poor. SFPW hired an outside consultant who found the same. Because there’s no longer a maritime need for a drawbridge – it hasn’t opened for marine traffic in more than a decade – the steel bridge will be replaced with a fixed-span concrete conduit. It’s slated to have a 26-foot-wide dedicated light-rail transit lane, four vehicle lanes, and two lanes for pedestrian/bicycle traffic. 

“This infrastructure project will bring critical life-safety improvements to this key connector between the Bayview and neighborhoods to the north,” said SFPW spokesperson Rachel Gordon. “The proposed replacement bridge will meet current structural and seismic standards and be more resilient to future sea-level-rise impacts.”

The area surrounding Islais Creek is at risk of flooding from heavy rainfall, coastal storm surge, and wave hazards, which’ll be exacerbated by sea-level rise and mounting groundwater, according to a joint Caltrans and SFPW environmental report. The bottom of the current bridge’s access hatches is at an elevation of 7.93 feet North American Vertical Datum of 1988 (NAVD88), below the anticipated 100-year storm surge of 9.86 feet NAVD88. 

SFPW has completed preliminary design work for the project and is in the environmental review process, which it hopes to have completed by the end of the year. A transportation analysis and transit and traffic detour plans are being developed. SFPW wants to minimize disruptions to the public during construction. Cars, buses, and pedestrians will likely be detoured around Third Street to surrounding routes. According to municipal officials, the T-line light rail will be replaced by a comparable shuttle bus service. 

District 10 Supervisor Shamann Walton said his office will work to mitigate negative impacts and ensure appropriate community input. 

“There will be no ideal scenario, but my hope is that all transportation strategies are effective and cause minimal disruption to the community,” Walton said in a statement. 

Once conceptual plans are finalized SFPW will begin designing the bridge, focusing on the details, which’ll take about a year to complete. The project could go out to bid in late 2026; construction may start in early 2027, with a two-year building duration. Proceeding, however, is contingent on identifying and securing the funding needed to complete the $60 million bridge replacement project. 

“We’ve already received $6.4 million from the federal government for preliminary engineering and for work to achieve environmental clearance,” Gordon said. 

The rest of the funds still need to be secured, potentially from the federal and state governments.