Exploring Big Slackwater

'High Road'

While complaining about the dreaded detour, people often forget about the section of the C&O Canal NHP that lies between Feeder Dam 4 (Mile 84.6) and McMahon’s Mill (Mile 88.1).  Hikers and bikers doing long stretches of the canal are forced to bypass this area because of the washed out section between miles 86.7 and 88.1.  Here, the Potomac runs up against a cliff wall, which makes further travel impossible.  Fortunately, this area is being repaired, and the towpath will once again be intact sometime during the Summer of 2012.

Great view of the Potomac River!



Until, then, the area between the dam and the cliff makes for a wonderful four-mile round trip hike.  Like many other canal buffs, we’ve never really given much thought to this area, but it does have a lot to offer in regard to historical structures and its close proximity to the Potomac River.



'Low Road'



The hiker has the choice of literally taking the high road or the low road (towpath) up to the guard lock for feeder dam 4. Surprisingly, the towpath is mowed and well-maintained, and the guard lock and inlet mark the spot where boats once left the canal and entered the river for approximately two miles.



Dam 4 Guard Lock



Rope Guides???




A gate near the guard lock that has been sealed much like the guard lock itself. This closure serves to keep flood waters out of the canal
















River Access

View of the Big Slackwater Project



Naturally, we had an ulterior motive and wanted to get a look at the work area for the Big Slackwater Project.  We did manage to walk to walk within approximately .5 miles of the construction site, and we’re pleased to say that a lot of progress has been made.  We’re looking forward to riding the entire length of the canal once again next summer, and this time–hopefully, no detour!


Winch House at Dam 4

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8 responses to this post.

  1. Posted by Bob G. on November 19, 2011 at 10:56 pm

    Great pics!


  2. Posted by LevelWalker on December 14, 2011 at 11:55 pm

    Thanks Bob! There’s lots to see on the canal!


  3. Like you did on my site, I have gone back to read some of your older posts. I thought I had read all of them before, but I am finding ones I had missed. It’s like discovering an extra piece of candy in the fold of the Christmas stocking!

    Hahn states at Lock 41 that one has the choice of the towpath on the berm or the roadlike path on the river bank. This isn’t true today as the original towpath is no longer serviced.

    You mention the old towpath above the winch house is well-maintained. I noted in my blog post in October that this stretch seemed to be reverting to nature. It appeared to me to be following the pattern at Lock 41.

    As I think about it now, I am not as sure of my conclusion. My hike was done right after the park reopened and, as we know, maintenance did not occur during the government shutdown. Nevertheless, the soft footing I experienced still leads me to think this strip will be abandoned sooner or later.


  4. Posted by LevelWalker on January 4, 2014 at 7:42 pm

    It’s hard to say about the stretch above the winch house. Maybe two years ago, the head of the level walkers asked if Candee and I would do a hike on the old towpath. It was mowed and in pretty good shape at the time. I enjoyed walking it because of the abundance of unripened paw paws along the way. We planned on going back and getting some, but we never made it. I agree 100% that riding a bike on this stretch is a bad idea.

    The story I heard is that there was a VIP work party (or something akin to that) a few years ago, and this section was cleared and mowed. Like you, I think the lack of funds that seems to always persist will lead to this section being one of the first things on the chopping block–unless a volunteer group of some sort takes an interest in it.

    As for the section above Lock 41, that’s news to me. The next time I’m over there, I’m going to take a closer look. There are lots of things in Hahn’s book that are long gone–like a mysterious canoe shed somewhere near the mouth of Sideling Hill Creek. There is an odd section of concrete above the aqueduct that may jibe with the shed, but who knows? It’s kind of fun reading Hahn and looking for scraps of things that pretty much no longer exist. As i learn to appreciate the C&O as something more than a bike path, it’s really intriguing to sort through the Rubik’s Cube of rubble in order to get an inkling of just how great the Great American Project really was.


    • The old bridge abutments can still be seen at the lower end of Lock 42. They consist of stone which is raised only a foot or so above the level of the lock. At some point, like the lock itself, they were faced with concrete (at least on the berm side). I have to think there was still a bridge in place (though probably not one from canal days) when Hahn wrote. In the summer, the abutments are covered in plants. If you have a picture of the lower end of the lock, you should be able to pick them out.

      This is a section I hiked 45 years ago with the Boy Scouts. It would be nice to have more of a memory of how it appeared back then, but I don’t. I’m simply grateful that that long ago hike hike created an interest in the C&O.


      • Posted by LevelWalker on January 4, 2014 at 9:52 pm

        The Boy Scouts have been an amazing part of the C&O during the park years. Their 184 Miles of Adventure towpath guide is arguably second only to Hahn as a park resource. During our second through ride, the section you’re speaking of was closed about a mile above the mill. It was “almost” as forgotten as the cliffs of the Big Slackwater project area for a time. In fact, there wasn’t a whole lot of action from Dam 4 up to about mm 90 or so. The first couple of bends upstream from the mill have some amazing river vistas, and the mighty Potomac floods the towpath quite a bit. During the Big Slackwater Project, some of the equipment was staged on the towpath above the mill. It’s a great place, but the graffiti artists have left their mark in spots.


  5. Posted by LevelWalker on January 4, 2014 at 7:58 pm


    I should mention that some of the older stuff on the site goes back about 2.5 years. Back then, we were operating without books and other resources, and I took some guesses about the exact locations of things. I need to go WAY back and take a closer look at some things. As Jamie points out, guides and other resources are a great thing to have when hiking on the towpath. For example, the steam pump ruins below Lockhouse 72 would make no sense at all without some sort of reference material. I learn something new every time… 1)somebody leaves a comment, 2) I take a hike, or 3) I pick up a book and read about the canal during its operational period. It’s an amazing place for both recreation and history.


    • One thing I like about your website is that recent comments are readily viewable on the blog. I do not have that capability with mine and I wish I did.

      As for the dates of your posts, it wasn’t clear to me at first in which year they were written. However, with a little practice I was able to figure out most of them. :)


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