The Monocacy Aqueduct — or C&O Canal Aqueduct No. 2 — is the largest aqueduct on the

Chesapeake and Ohio Canal The Chesapeake and Ohio Canal, abbreviated as the C&O Canal and occasionally called the "Grand Old Ditch," operated from 1831 until 1924 along the Potomac River between Washington, D.C. and Cumberland, Maryland. It replaced the Potomac Canal, ...

, crossing the

Monocacy River The Monocacy River () is a free-flowing left tributary to the Potomac River, which empties into the Atlantic Ocean via the Chesapeake Bay. The river is long,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data ...

just before it empties into the

Potomac River The Potomac River () drains the Mid-Atlantic United States, flowing from the Potomac Highlands into Chesapeake Bay. It is long,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map. Retrieved Augu ...

in Frederick County, Maryland, USA. The 438 foot (133.5 m) aqueduct was built by three separate contractors between 1829 and 1833 at a cost of US$127,900.

Description

The aqueduct is a stone masonry structure with a waterway of 19 feet at the bottom and 20 feet at the top. The towpath parapet wall is 8 feet wide and the upstream wall is 6 feet wide.

Benjamin Wright Benjamin Wright (October 10, 1770 – August 24, 1842) was an American civil engineer who was chief engineer of the Erie Canal and the Chesapeake and Ohio Canal. In 1969, the American Society of Civil Engineers declared him the "Father of America ...

, the project's chief engineer, drew the plans with 6 piers, 2 abutments and 7 arches, each with a span of 54 feet. The piers are 10 feet thick with a pilaster at each end. The aqueduct is 438 feet in length. Much of the building material was large quartzite stone blocks quarried at the base of nearby

Sugarloaf Mountain Sugarloaf Mountain ( pt, Pão de Açúcar, ) is a peak situated in Rio de Janeiro, Brazil, at the mouth of Guanabara Bay on a peninsula that juts out into the Atlantic Ocean. Rising above the harbor, the peak is named for its resemblance to ...

History

The first contract for the aqueduct was awarded in August 1828 to Hovey and Legg, which began work in 1829. The contract was next awarded to Asher Osbourn, but by the end of 1830, it was in the hands of Byrne and Lebaron. During the

American Civil War The American Civil War (April 12, 1861 – May 26, 1865; also known by other names) was a civil war in the United States. It was fought between the Union ("the North") and the Confederacy ("the South"), the latter formed by states ...

the Union used the canal to transport war materials and troops along the border between

Maryland Maryland ( ) is a state in the Mid-Atlantic region of the United States. It shares borders with Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware and the Atlantic Ocean to ...

Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth ar ...

, and points west. For this reason, the canal and the aqueducts were often under Confederate attack. There were many Confederate sympathizers among the canal employees, including Thomas Walter, keeper of Lock 27. Walter loved the South, but he loved the Monocacy Aqueduct more. When he learned that Confederate General D. H. Hill had orders to destroy it in order to halt boat traffic during the

Antietam The Battle of Antietam (), or Battle of Sharpsburg particularly in the Southern United States, was a battle of the American Civil War fought on September 17, 1862, between Confederate Gen. Robert E. Lee's Army of Northern Virginia and Union G ...

campaign in September 1862, Walter convinced Hill that draining the canal would achieve the same end. Walter saved the Monocacy Aqueduct, only for it to be threatened once again a few days later when another Confederate party attempted to blow up the aqueduct. However, the soldiers were unable to drill enough holes into the hard stone to place enough explosives to breach the structure.

Granary

150px, Ruins of Monocacy village granary Like at Whites Ferry, a

granary A granary is a storehouse or room in a barn for threshed grain or animal feed. Ancient or primitive granaries are most often made of pottery. Granaries are often built above the ground to keep the stored food away from mice and other animals ...

was built here, having three storage bays, two passageways for the boats, and only one story.NPS publication ''Granaries at Whites Ferry and Monocacy Village'', undated The remains of the granary are next to the parking lot.

Current status

The aqueduct is part of the C&O Canal National Historic Park and is administered by the

National Park Service The National Park Service (NPS) is an agency of the United States federal government within the U.S. Department of the Interior that manages all national parks, most national monuments, and other natural, historical, and recreational propert ...

. Following damage caused to several canal structures caused by

Hurricane Agnes Hurricane Agnes in 1972 was the costliest hurricane to hit the United States at the time, causing an estimated $2.1 billion in damage. The hurricane's death toll was 128. The effects of Agnes were widespread, from the Caribbean to Canada, ...

and other flooding incidents in the early 1970s, the

and the

Federal Highway Administration The Federal Highway Administration (FHWA) is a division of the United States Department of Transportation that specializes in highway transportation. The agency's major activities are grouped into two programs, the Federal-aid Highway Program ...

designed a steel banding system to stabilize the structure and installed a steel rod reinforcing system. The National Park Service and park supporters were concerned about the structural stability of the aqueduct and a major engineering evaluation was undertaken to determine stabilization needs and associated cost. The C&O Canal National Historical Park and its partners restored the aqueduct to its original appearance in 2004-2005. The aqueduct was formally rededicated in May 2005.

References

* National Park Service, Hagerstown, MD (2013)
"The Monocacy Aqueduct: An Icon of American Civil Engineering."
* Smithsonian Associates, Washington, D.C
"The Monocacy Aqueduct."
Smithsonian Associates Civil War E-Mail Newsletter, Volume 5, Number 7. Accessed 2013-01-09.

External links

* {{coord, 39, 13, 25, N, 77, 27, 7, W, display=title Transportation buildings and structures in Frederick County, Maryland Navigable aqueducts in the United States Monocacy River Chesapeake and Ohio Canal Water transportation in Maryland