Semi-annual maintenance welding to the steel grate deck of the Hood River-White Salmon Interstate Bridge will begin Monday, and helicopter service to repair overhead utility lines on November 10 will require intermittent closures of the bridge.  The Port of Hood River says there will be single lane closures of the bridge with flaggers directing traffic between 8 a.m. and 3 p.m. weekdays starting Monday through November 24.  Motorists should expect delays of approximately 15-25 minutes throughout the day, depending on traffic volume.  There will be three, 30-minute total closures of the bridge next Wednesday to allow a helicopter to service the overhead telecommunication utility line.  The bridge will be closed to all vehicle traffic on that day between 9:00 and 9:30 a.m., 10:30 and 11:00 a.m., and 12:30 and 1:00 p.m.