WHILBR - Western Maryland's Historical Library
Images and text by Leslie J. Carter
“Go view those magnificent ... culverts, of hewn stone ... then think how soon the fortunes of individuals embarked in the prosecution of such an enterprise would be swallowed up ... It will not be deemed out of place, if I here express the hope, that those ... should not in the hour of its prosperity be forgotten.”
[From speech by William Price, Cumberland, Md. canal promoter, given at formal opening ceremonies for the C&O Canal, October 10, 1850 (Unrau, 676).]
This project was inspired by a comment in Thomas F. Hahn’s Towpath Guide to The C&O Canal (25th anniversary edition, 1997, sadly out of print). He wrote of the Rock Run culvert (at Mile Post 8.93): “This culvert is a fine example of one of outstanding structures under the canal which most do not see. Recommended for viewing; carefully work your way down to stream it carries to see if you don’t agree.” (Hahn, 32) I’d grown up within walking distance of the C&O Canal and have biked its entire length; I had thought I’d seen it all. Revisiting the Canal to find and photograph all the culverts Hahn listed in his Guide gives a fresh new view of this 184.5 -mile long National Park, for attraction features that are best enjoyed during the winter (to avoid snakes and poison ivy). I wholeheartedly agree with the late Mr. Hahn!.
William E. Davies described the C&O’s culverts in his Geology And Engineering Structures of the Chesapeake And Ohio Canal: “It was the practice of the canal engineers to keep streams from draining into the canal. The canal was carried across streams by single arch, masonry culverts ... The arch in the barrel of most culverts was rubble bonded by cement. Faces of the culverts ... were dressed masonry. Earthen embankments bound the prism over the culverts [this is a principle difference between the culverts and the aqueducts]... Stone for most structures was obtained locally except for a few ... culverts in the Georgetown area where Aquia Creek freestone, quarried 35 miles (56 km) south of Washington, was used.” (Davies, xiii) The historic culvert could be described as a buried single-arched aqueduct. A few, like the Little Tonoloway culvert (#182) are magnificent in scale. The line blurs in the Broad Run Trunk (#44): unique in its original two-arch design (washed away in an 1846 flood), this culvert was rebuilt as an aqueduct with a wooden coffer. C&O Canal, NHP has concluded this one is an aqueduct, but I include it here simply because it started out as a numbered culvert. For that matter, I do not include the non-historic culverts that were added to the Canal after its operating period ended in 1924..
Although the Guide lists 241 historic stone culverts, not all of them can be found. Elizabeth Kytle’s Home On The Canal puts the number at “more than 150” (Kytle, 65), while Davies claims there are 182. Hahn cautioned, “Many of the ‘lost culverts’ apparently were abandoned because of the tremendous amounts of silt which were carried, making the cleaning out of the culvert almost mandatory after each heavy rain ... [These] features must be added or deleted (whether or not the canal is watered) as the surrounding drainage patterns change.” (Hahn, 67) An example of this fact can be seen in the ongoing loss of Culvert #95. Each culvert is additionally threatened with conditions that can lead to their collapse: floods, invasive roots from trees and other nearby vegetation, encroachment by highways and railroads, vandalism, even simple neglect. Hahn further comments, “It is important that culverts be repaired and restored ... This is one of the best investments the Park Service can make.” (73) The maintenance of this National Park, like nearly all others today, is underfunded and understaffed. That the culverts I found are as in good shape as I recorded is a testament to the devotion of a stretched-thin staff.
The C&O Canal, NHP lists over 1,300 historic structures within this park, including the culverts. Many visitors are familiar with the locks, the lock houses, and the magnificent aqueducts, most of which are very fine examples of stone masonry rarely practiced today. Although not as dramatic as the aqueducts, the culverts’ stone work is no less fine, and each are worth the scramble down the embankments to be seen. Time to give the lowly canal culvert its due!
Western Maryland Regional Library is most grateful to Leslie Carter for sharing her photographs and research with us. This unique collection adds to the understanding of the construction and beauty of the Chesapeake and Ohio Canal.
This website includes the photographs of the culverts that Leslie took along the canal in Washington County, Maryland. The mile shown is the mileage from the terminus at Georgetown, shown on the mileposts familiar to those who have walked the towpath. When the canal was constructed, each aqueduct, lock and culvert was put out to bid, with each numbered for accounting purposes. Culvert at "Mile 100.23. Historic culvert number 129", is 100 miles from Georgetown and it was given the number 129 when constructed.
For each culvert or feature, Leslie includes her own comments plus any useful information such as the name of the stream of water carried by the culvert, its original construction date, possible reasons for any missing or vanished material (for example, many inflow portals have been obliterated by the close proximity of rail lines), etc.
Barrel Vault or Barrel - arched masonry construction forming a tunnel
Berm - canal bank opposite from towpath
Castellated - detail formed by equal-size openings and segments of a low wall, as in a castle
Keystone - prominent wedge-shaped stone inserted at the top of a curving masonry arch
Prism - cross section of canal construction: formed by sloping banks and the bottom of the channel
Rip Rap - randomly piled construction materials, such as stones or timbers, to temporarily reinforce or replace a foundation
Tail Race - the outflow channel of a water-powered mill
Towpath - a trail on the bank of the canal, used by mules to tow a boat along the canal.
Trabeated - square arch formed by two vertical members topped with a horizontal beam
Waste Weir - a slatted gate built into a canal bank to allow excess water to be drained off