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The History of the Conococheague Aqueduct at Cushwa Basin

May 11, 2017

The History of the Conococheague Aqueduct at Cushwa Basin

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By Tim Snyder, Historian, C&O Canal Association

On April 29, 1920, the berm wall of the Conococheague Aqueduct collapsed and a canal boat plunged into the creek below. It was not the first time—nor the second—that the aqueduct’s berm wall had given way.

The Conococheague Aqueduct was the fifth of eleven stone aqueducts that the C&O Canal Company had built to take the waterway over the major tributaries of the Potomac. The aqueduct was designed by engineer Thomas F. Purcell and built by Michael Byrne & Co. Byrne was an Irish immigrant who had previously worked on a canal in Pennsylvania. Byrne sub-let at least some of the work to other contractors, including Edward Fielding, who completed the wing walls. The structure was built in 1833–1834, although some exterior details were not completed until late 1835, after the aqueduct was in use. The completed aqueduct consisted of three 60-foot arches and was the second largest aqueduct on canal, 196 feet between its abutments, 210-foot overall. Being located at Williamsport—an important crossroads town near the middle of the waterway—the Conococheague Aqueduct had more decorative features than most, including engaged pilasters with ornate capitals and bull-nosed piers.

During the Civil War, on more than three occasions, military forces tried to destroy the aqueduct. The first occurred during the Battle of Antietam when Union Gen. George B. McClellan ordered cavalry to Williamsport to burn the bridge over the canal and destroy the aqueduct. The order was likely intended to prevent the Confederates—who were holding the Virginia side of the river—from crossing the Potomac and getting in the rear of McCellan’s army. The aqueduct suffered little damage on this occasion.

The second attempt occurred during the 1863 invasion that culminated in the Battle of Gettysburg. Confederate troops began to ford the river into Maryland at Williamsport on June 15, and officers dispatched pioneers to tear apart the aqueduct. The crews tore out the four corners of the aqueduct down to the bottom of the canal and removed enough stone to create a ten-foot gap in one of the arches. Other attempts took place during the Confederate invasions of Maryland during the summer of 1864 by Early and others. Again the aqueduct was damaged, although less extensively than in 1863.

On March 5, 1865, as the war drew to a close, a portion of the berm wall of the Conococheague Aqueduct collapsed for the first time. The Williamsport superintendent explained that there had been a crack in the masonry since before the war, and that blasting by the Confederates and the recent winter freeze had likely caused the wall to topple. The hole in the wall was ninety-five feet, although repairs were expected to extend over one hundred twenty-four feet. In three weeks the aqueduct was restored with a wooden trunk rather than stone, and would remain in this condition for the remainder of the decade until the wall was rebuilt with masonry in 1871.

Another partial collapse of the wall occurred less than a decade later. On March 11, 1877, at the beginning of the boating season, a twenty foot section of the berm wall fell. The Hagerstown Mail reported that the canal company expected to complete the repairs in about 10 days.

Then about 5:00 a.m. on the morning of April 29, 1920, Boat Number 73, piloted by Captain Frank Myers of Big Pool, was heading up the canal toward Cumberland after unloading his cargo at Steffey and Findlay’s wharf at Williamsport. With the boat in the chamber of the Conococheague Aqueduct, the berm side wall wavered and two-thirds of it collapsed. Some accounts say that the boat had bumped against the wall. Just before the wall gave way, Myers called for the tow boy (his stepson) to unhitch the tow lines, which saved the mules from being killed in the accident. As the wall began to fall, Myers leapt onto the lower parapet, which remained intact and gave the captain refuge from the misfortune. The boat was swept into the creek twenty feet below. After the accident, the canal company removed most of the remaining portion of the wall and replaced it with a wooden trunk supported by poured concrete. The repairs took about a month to complete. During the remaining four years of the canal’s use, the wooden berm wall remained in place until the Great Flood of 1924 ended boating on the canal. Since that time, the wood has rotted away, leaving the majestic structure without one of the essential features of an aqueduct.

The restoration of the Conococheague Aqueduct will officially commence on May 5, 2017 with a ground breaking ceremony at Williamsport. When completed, the renovation will return the aqueduct to its appearance in 1920 after the installation of the wooden trunk, displaying one of the practical cost-saving measures that the canal company sometimes utilized to keep the boats moving in a highly competitive economic environment. The restored aqueduct will also serve as a reminder of the importance that Williamsport and the C&O Canal played in this nation’s history.