Dam 6 is located at mile 134.1 on the Chesapeake and Ohio Canal. The walls that anchored the dam still exist on the Maryland and West Virginia shores, as does much of the rubble that once filled a wooden frame that made up the structure. The interpretive sign at the site shows how the dam looked when it was operable, and it’s easy to see why it wasn’t nearly as successful as the still existing dams four and five. Nevertheless, the dam’s location and twin channels running on either side of the towpath for approximately .2 miles are important keys in learning some of the basic operations of the canal.
On first glance, there appears to be two locks and two canals just below where the dam once stood, and this is at least partially true. The lock closest to the river is a guard lock, and this is where water was let into a channel that joined and fed the canal just downstream. Today, a large slab of concrete fills the gap where water entered the feeder channel, much like what one sees at the guard lock about a mile above Dam 4. Why? Having the Potomac’s waters fill the canal while it was operable was an asset, but today an unblocked guard lock could be very destructive to the park’s recreational value.
The other lock is Lift Lock 55, which, of course, is one of the many locks used to lift or lower boats as they plied the waters of the C&O. Thus, this is the actual channel of the C&O itself. Heading downstream, the guard lock’s feeder channel joins the canal just below Lock 54. Today, Lock 54 has–for the most part–been filled in, and just to the right, the towpath navigates a dip which carries it through the feeder channel and across a large pipeline. Just to the left, beyond two small piers, one can see where the guard lock channel joins the canal and once kept it watered until Dam 5 took over 27 miles downstream. We all love to hike, bike, and nature watch, but this part of the C&O Canal is a great place to channel one’s inner engineer or historian.