Caltrans closed three southbound I-680 lanes in Walnut Creek the night of Monday, Sept. 21, for drainage work. It was the third time the agency shut down I-680 in the Walnut Creek area since August.

Lanes 4, 5 and 6 between Monument Boulevard and South Main Street were closed from 9 p.m. to 4:30 a.m., Caltrans District 4 said on X. The Gregory Lane/Monument Boulevard off-ramp was fully closed from 11 p.m. to 5 a.m.

The agency urged drivers to slow down and stay alert in the work zone.

Recurring closures

The Monday, Sept. 21, shutdown was not a one-off. Caltrans ran the same overnight closure on the identical I-680 segment on Sept. 17, with the same lane and ramp restrictions on the same schedule. The agency also closed lanes on both northbound and southbound I-680 for drainage work on Aug. 19, though that post did not specify whether the closure covered the same Monument-to-South Main segment.

That adds up to three overnight closures in roughly five weeks on I-680 in Walnut Creek.

Caltrans has not announced a project timeline or said how many additional nights of work remain. The agency has not identified the drainage project by name or released details about its scope.

Drivers heading south on I-680 late at night can check Caltrans QuickMap for real-time lane and ramp closure information. Caltrans District 4 also posts closure notices on its X account, @caltransd4, ahead of overnight work.