U.S. Corps of Topographical Engineers
William Turnbull, engineer, born in Philadelphia, Pennsylvania, 9 October, 1800; died in Wilmington, North Carolina, 9 December, 1857. He graduated from the United States Military Academy in 1819, and entered the army as 2d lieutenant in the artillery. After serving in garrison at Fort McHenry for a year he was on topographical duty until 1832, being made in 1831 assistant topographical engineer, with the brevet of captain. From 1832 till 1843 he was superintending topographical engineer of the construction of the Potomac aqueduct. This work, one of the earliest of the important undertakings of American engineers, gave Colonel Turnbull a high rank among his professional associates. The piers of the aqueduct were founded by coffer-dams on rock, sometimes covered by twenty feet of mud, and nearly forty feet below the water surface. He was made major, 7 July, 1838, and had charge of the repairs of the Potomac (long) bridge in 1841-'3. Subsequently he had charge of Lake Ontario harbor improvement, the extension of Buffalo harbor, and inspection of harbor improvements on Lake Champlain, Lake Ontario, and Lake Erie. In the war with Mexico he was topographical engineer of the army under General Winfield Scott, and was engaged in the siege of Vera Cruz, the battles of Cerro Gordo, Pedregal, and Churubusco, and the operations that ended with the capture of the city of Mexico. His services gained for him the brevets of lieutenant-colonel and colonel. During 1848-'9 he had charge of the construction of the New Orleans custom-house, and he was assistant in the Topographical Bureau at Washington, D. C., in 1850-52 and 1853-54, where he examined the practicability of bridging the Susquehanna river at Havre de Grace, and the expediency of an additional canal around the Falls of Ohio. He was light-house engineer for Oswego harbor, New York, in 1853-55, in charge of harbor improvements of Lake Champlain, Lake Ontario, and the eastern part of Lake Erie in 1853-56, and of the improvement of Cape Fear river, North Carolina, in 1856-57. Among his various government reports that were published was one "On the Survey and Construction of the Potomac Aqueduct," with twenty-one plates (Washington, 1838).
Appletons Encyclopedia