The Ohio River: A Physical Description
The Ohio River is formed by the confluence of the Allegheny and Monongahela rivers at Pittsburg, Pennsylvania. It flows generally south and west 981 miles to the Mississippi River while forming the border between five states after leaving Pennsylvania. Portions of 11 states drain into the Ohio River representing 20 percent of the Mississippi River watershed.
The original river bed dropped a half foot per mile resulting in a shallow, fast-flowing stream completely unlike the river we know today. Can you imagine wading across the Ohio River when it was only one foot deep; a series of pools and riffles with an occasional waterfall? Navigation was obviously difficult. A commission of Ohio Valley states identified 102 obstructions to navigation between Pittsburg and Louisville in 1820. Congress helped fund this survey with a $5,000 appropriation that marked the start of federal water resource programs in the United States.
Improvement of navigation on the Ohio River was begun by the U.S. Army Corps of Engineers in 1825 with dredging of sandbars and removal of snags. The first lock and dam was completed in 1885 about five miles below Pittsburg, and 12 more were built in 1910. Channelization of the river was completed in 1929 with 50 low lock and dam structures in operation. This system was eventually replaced by 20 high-rise lock and dams that now maintain a 12-foot channel for commercial navigation. The river is a series of slow-moving lakes, some as long as 100-miles and 50 feet in depth.
Commercial navigation on the Ohio River and other channelized basin streams amounts to about 25 percent of the total inland waterway freight tonnage in the United States. The annual traffic on the Ohio River averages more than 150 million tons. Most of the freight traffic is made up of bulk forms of energy: coal, crude oil, and petroleum products. Other major commodities transported include sand, gravel, iron and steel, chemicals, and grain.
Bottomlands of the Ohio River basin are subject to occasional damaging floods. A system of reservoirs and local protection projects now in operation throughout the basin is capable of reducing annual flood damage by more than 50 percent.