The 4th Street Grade in The Dalles is closed to traffic beginning Monday as a sewer line is installed.  The closure runs from Jefferson Street up the grade to East 8th Street.  It is a total closure with local access to adjacent residents only, and is expected to run through June 30.  Motorists are being re-routed via E. 8^th Street to Kelly Avenue and Washington Street.  The detour route will be signed.