Construction and early history The Falls of the Ohio, historically, was the only natural obstruction in the entire length of the Ohio River, with a rock reef forming a rapids of nearly 3 miles. "As early as the year 1802, the expense and delay attending the reshipment of freight around the falls had become so serious that numerous plans were proposed for overcoming the obstruction," according to the Corps of Engineers, leading to the construction of the Louisville and Portland Canal. The first boat passed through the canal December 22, 1830. In the ensuing decades, many vessels on the Ohio River were too large for the locks, leading to more alterations to the infrastructure and culminating "in a combined navigation and hydroelectric development" in the 1920s. The dam for generating
hydroelectric power was added in 1927. The hydroelectric plant at the time was the seventh largest hydroelectric plant in the United States, and in its early years of operation, "provided most of the power needed to serve the city of Louisville," according to
LG&E and KU. Today, it has a net generating capacity of 110
megawatts with eight turbine units in service. 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. In October 2003, McAlpine was designated a
Historic Civil Engineering Landmark by the
American Society of Civil Engineers.
Modernization The McAlpine locks underwent a 10-year, $278 million expansion project, completed in 2009. "This work replaced the 600’ and 360’ locks with a 1200’ x 110’ lock on the Kentucky bank side of the Louisville and Portland Canal adjacent to the existing lock," according to the Corps, "for efficient movement of projected increases in tow traffic." The original bridge carrying 27th Street across the locks, built in 1926–1927, included two
moveable spans – one
swing span and one
bascule span – but these were removed in 2007 and replaced by a new two-lane, high fixed-span concrete bridge. In 2019, the hydroelectric station also saw a modernization project, meant to give the dam another century of life. The station received some technological improvements, and computer modeling helped shape the turbines for maximum performance. "Even with these modern changes, much of the facility’s hardware remains intact from the 1920s," according to the utility. "The plant has retained its historic charm with original tile floors, wooden handrails, ornate light fixtures and a vintage control room." ==See also==