Mile 13.74 - A nearby plaque reads: Structures such as this stop-lock were designed to divert flood waters from the canal.  Wooden planks were dropped into the slots, forming a dam which diverted rushing waters along a stone levee and back into the Potomac.

The levee is a long hill, perpendicular to the canal that stretches to the river.  The stop gate is part of the levee. 

These are a few of the shorter planks inserted into slots in the stone walls.  They only need to be as wide as the canal.  Longer planks are needed to stretch across the width of the stop gate.

During the times when Widewater is flooded or otherwise damaged, this is the other end of the detour around the rocky section near Lock 15.  You cross over here to Berma Road to come out at Old Angler's Inn.  Although there's little detour signs all over the stop gate, if you miss them anyway, the rocky section is not so bad on bike and no problem on foot.