New Yorks Erie Canal

Like many large civil projects, building the Erie Canal required leaders with vision, political prowess, and technical ingenuity. The concept of a canal connecting the Hudson River with Lake Erie generally is credited to then New York Gov. DeWitt Clinton in 1808. One source, however, notes a proposal for such a canal by Cadwallader Colden, the New York surveyor general, in 1724.

Regardless, it was Clinton who, in spite of opposition calling the project "Clinton’s Folly" and "Clinton’s Big Ditch," convinced the New York state legislature in 1817 to authorize $7 million to build the 363-mile-long canal. However, with a scarcity of formally educated engineers in the United States at the time—the country did not have any engineering schools yet—design and construction of the canal was a a challenging proposition.

The project’s chief engineer, Benjamin Wright, was a surveyor with little formal education. He learned surveying from an uncle and practiced his trade in the wilderness of upstate New York. Originally, he was selected as one of three engineers assigned to design and build one section of the canal, but after two years of construction, he was appointed chief engineer. Wright later became the first chief engineer of the Erie Railroad and chaired the first committee seeking to establish an American Society of Civil Engineers. He has been called the father of American civil engineering.

 Construction of the 363-mile Erie Canal took about 8 years and employed thousands of workers. Its success sparked a period of canal building in the United States.

The Erie Canal, completed on Oct. 26, 1825, after a little more than eight years of construction, included 18 aqueducts spanning valleys and rivers, and more than 80 locks providing a total rise of about 570 feet from the Hudson River to Lake Erie. A standard section of the canal was 40 feet wide at the water surface, tapering to 28 feet at the bottom of the canal, with 6-foot-high berms on either side, creating a water depth of 4 feet. A 10-foot-wide towpath for horses, mules, and oxen was built along the top of one of the berms. Early canal barges were 70 feet long, 7 feet wide, and had sufficient draft to carry up to 30 tons of freight—about 1,000 bushels of grain.

Relatively inexpensive freight rates and significantly shorter travel times between the East Coast and the Great Lakes region ensured the immediate success of the Erie Canal. According to a U.S. Army Corps of Engineers paper by Robert Harrison, "History of the commercial waterways and ports of the United States," a team of four horses pulling a wagon on a typical road in 1800 could haul 1 ton about 12 miles a day. On a canal with a towpath, one horse could pull a 30-ton barge at about 2 miles per hour. Freight rates from Buffalo to New York City were $10 per ton by canal, compared to $100 per ton by road. Canal construction costs were recouped in nine years in spite of the fact that total costs reached more than $12.7 million (equivalent to about $225 milllion today), including construction of feeder canals. "Measured in terms of water moved, it was the greatest water resource project of the 19th century," wrote Harrison.

Nevertheless, the Erie Canal had its problems. Development of the feeder canals to keep the main canal supplied with water was a major undertaking, according to Harrison. Hydrologic engineering problems plagued the canal, often causing a shortage of water. The cross section of the original canal proved to be too small to move the volume of water needed to maintain water levels between feeder streams, Harrison reported. Seepage out of the canal was greater than had been estimated.

Beginning in 1836, the Erie Canal was deepened to 7 feet. This enabled use of barges that could carry up to 240 tons. Although freight transport on the Erie Canal declined as railroads and good roads were built, sections of the canal remain in use today, primarily for recreational boating. Read about the design and construction of New York’s George Washington Bridge in the April 2004 issue of Structural Engineer.

Posted in Uncategorized | January 29th, 2014 by

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