Walnut Creek residents who drive southbound I-680 through Pleasant Hill will lose two lanes and a freeway on-ramp six nights a week starting Monday, July 20, as Caltrans begins emergency storm-damage repairs expected to last more than six weeks.

The closures affect the stretch between Willow Pass Road and the Monument Boulevard off-ramp, the segment immediately north of the SR 24/I-680 interchange. Caltrans will shut down the two rightmost travel lanes (Lanes 4 and 5), the right shoulder, and the Willow Pass Road on-ramp to southbound I-680 every Monday through Saturday from 8 p.m. to 5 a.m.

The work is scheduled to continue through Friday, September 4, though Caltrans called that completion date "tentative" in a traffic advisory published Wednesday, July 15.

Why the repairs are needed

Winter storms damaged the roadway badly enough that Caltrans classified the project as an emergency. According to the agency's advisory, the storms caused pavement to settle, eroded the embankment, and broke the highway's drainage system.

Crews will start with compaction grouting, a process that injects grout under pressure to stabilize the roadway foundation beneath the buckled pavement. Later phases include pavement repairs, dike replacement, drainage system fixes, slope reconstruction, and permanent erosion control work.

Caltrans said the repairs are necessary to restore the road's structural integrity and prevent further settlement.

What drivers should expect

Electronic message signs will alert motorists approaching the construction zone. Caltrans advises drivers to expect delays, prepare to merge early, and allow extra travel time.

The agency did not name a specific surface-street detour. Drivers can check real-time conditions on Caltrans QuickMap at quickmap.dot.ca.gov or follow @511SFBAY on X for updates.

A free transit option

Drivers heading out after 8 p.m. have a no-cost alternative for part of the closure window. County Connection's Route 14 shuttle runs free between Walnut Creek BART and Concord BART every weekday from 5:30 a.m. to 9:30 p.m., with stops at Monument Boulevard and Pleasant Hill BART. Buses depart every 30 minutes. The free Route 11 shuttle also connects Pleasant Hill BART and Concord BART weekdays from 6 a.m. to 8 p.m., serving the Monument Corridor alongside the affected freeway segment.

No project cost has been publicly disclosed. Caltrans District 4 did not provide a named spokesperson for the project.