The McAlpine Locks and Dam refers to the series of locks and the hydroelectric dam in Louisville, Kentucky at the Falls of the Ohio. They are located at mile point 606.8 and control a 72.9 mile (117 km) long navigation pool. This was the first major engineering project on the Ohio River, and the first official name of the system of canal locks was the Louisville and Portland Canal, which was completed in 1830 to allow shipping traffic to navigate through the Falls of the Ohio. From 1925 to 1927, a dam for generating hydroelectric power was added, and the system of canals was expanded, first by a private company and then by the U.S. Army Corps of Engineers. The hydroelectric plant at the time was the seventh largest hydroelectric plant in the United States.
The system was renamed the McAlpine Locks and Dam in 1960 in honor of William McAlpine, who was the only civilian to have ever served as district engineer for the Corps of Louisville. At present, the normal pool elevation is 420 feet (130 m) above sea level and the drainage area above the dam is 91,170 square miles (236,000 km²). The average daily flow at McAlpine is 118,000 cubic feet per second (3,340 m³/s). The lock chambers are located at the dam on the Kentucky side of the Ohio River and are capable of a normal lift of 37 feet (11 m) between the McAlpine pool upstream and the Cannelton pool downstream. The hydroelectric plant consists of eight turbine units with a net power generation capacity of 80,000 kilowatts. The hydroelectric plant is currently undergoing an 8-year long rehabilitation project. This will extend the life of the 1920s era turbine-generator units and increase power output to 100 megawatts.
In October 2003, McAlpine was designated a Historic Civil Engineering Landmark by the American Society of Civil Engineers.
The McAlpine locks underwent a 10-year, $278 million expansion project scheduled to be completed in 2008, but was completed in early 2009.
The hydroelectric plant is owned and operated by Louisville Gas & Electric, a subsidiary of PPL Corporation while the locks are operated by the Army Corps of Engineers.