From the Harwich Police Department:
Starting this Thursday, utility work will begin on Depot Street between Old Chatham Road and Main Street. A company will be replacing water services which will necessitate the closing of the road.
A detour will be in place and the road will be closed to everyone except residents. There will be a trench across the road making it impassable.
So, if you decide that the detour signs do not apply to you, you will be turned around and sent back the way you came from.