An Oak Harbor resident’s observation at Deception Pass Bridge led to a $750,000 project that will affect nighttime traffic over the bridge this fall.

Work on the waterlines running under Deception Pass Bridge will mean a lane closure Monday night, followed by a month of nightly lane closures beginning in October, according to the Washington State Department of Transportation.

Two years ago, a resident noticed some of the bridge hangers holding the water mains on the bridge were rusting through and sent photos to the city.

In response, the city contracted with Gray & Osborne to inspect the water mains attached to the bridge.

The consultant recommended replacing many of them; the city is replacing all of the hangers, which is “the only efficient way of performing this task,” according to the council’s agenda bill on the issue.

Oak Harbor gets most its water from the Anacortes treatment plant on the Skagit River in Mount Vernon, which is piped all the way to the city. An older 10-inch steel pipeline and a newer 16-inch steel pipeline brings the water across the bridge, according to the city.

Hangers attach the pipes to the bridge.

The council approved an agreement with Gray & Osborne last year to design a new hanger system at a cost not to exceed $60,000.  The city originally planned to have the work completed by April 30.

In August, the council approved a $686,000 bid from Bridge Masters, Inc. to do the construction work.

The contractor crews will do some pre-construction work from 8-11:59 p.m. Monday, Sept. 12. They will close a lane nightly and flag traffic through the open lane on weeknights when work resumes Tuesday, Oct. 11, until approximately Wednesday, Nov. 9.

Overnight weekday work starts 8 p.m. and finishes by 5 a.m. each day.

Travelers in the area can get real-time traffic information on their phone with the WSDOT traffic app, by tracking the WSDOT traffic Twitter feed, and get advanced information from the Mount Baker area construction page.