Appalachian History Series
Along a bend of the Ohio near Lloyd, Kentucky, the Greenup Locks and Dam turned a troublesome stretch of river into a predictable navigation pool and later became home to one of the valley’s most productive municipal hydro plants. What the Corps built here in the late 1950s and early 1960s replaced four aging wicket dams on the Ohio and one on the Big Sandy, shortened lockages for modern tows, and anchored a new era of river commerce for communities from Ashland to Portsmouth.
From wicket dams to a “super dam”
Early 20th-century wicket dams gave the Ohio a nine-foot channel, but by midcentury their small 600-foot locks and fickle pools could not keep pace with longer tows and heavier traffic. Planning for a modern high-lift project at Greenup followed, with the Corps siting it about five miles below Greenup at Ohio River mile 341. The new project was designed to replace Ohio River Locks and Dams 27 through 30, plus Big Sandy River Lock and Dam No. 1.
Building Greenup
Corps records place the start of lock construction in 1955 and initial lock operation on November 27, 1959. Dam construction began in June 1958 and the project was formally accepted for operation on July 21, 1962. The complex included a 1,200-by-110-foot main lock and a 600-by-110-foot auxiliary lock, a movable dam with nine tainter gates, and a normal pool elevation that extended upstream to what is now Robert C. Byrd Locks and Dam as well as to Meldahl on the Ohio side. Costs recorded through June 30, 1963 were a little over 55 million dollars.
What changed on the river
The twin-chamber design and deep, stable pool reduced waits and allowed standard tows to pass in one cut rather than breaking apart for short chambers. Greenup’s pool ties into the Corps’ Ohio River navigation system and is charted in federal navigation atlases for pilots moving everything from coal and petroleum to grain and aggregates.
Today the project sits within the Huntington District’s real-time water management network. Operations and pool data appear on the Corps’ public portal, and stage and flow are tracked at the federal USGS gage “Ohio River at Greenup Dam near Greenup, KY” as well as in NOAA’s National Water Prediction Service under station GNUK2. These datasets are the backbone of navigation and flood communication for the reach.
Hydropower at Greenup
The City of Hamilton, Ohio pursued a non-federal hydro plant at the dam under a Federal Energy Regulatory Commission license first issued in 1976. The 70.2-megawatt facility entered commercial service in 1982 and has typically produced in the neighborhood of 260 to 280 gigawatt-hours annually. In 2016 Hamilton sold a 48.6 percent interest to American Municipal Power, and the two entities now co-own and operate the project. In February 2024 the co-licensees tendered their application for a new major license with FERC.
Modern upkeep and continuing importance
Like every hard-working lock, Greenup has seen major maintenance. The main lock’s riverward miter gates were replaced during a 2016 closure window, part of a continuing effort to keep one of the district’s busiest navigation chokepoints reliable. The Great Lakes and Ohio River Division also notes a significant gate replacement effort earlier in the 2010s and provides the project’s authority and cost figures for the modern system.
Authority for future capacity
To improve reliability and reduce delay during main-chamber outages, Congress authorized extending Greenup’s 600-foot auxiliary chamber to 1,200 feet in the Water Resources Development Act of 2000. The Chief of Engineers’ interim report for the Ohio River Mainstem Systems Study detailed the plan to lengthen the auxiliary lock and add long floating guide walls.
Where to find Greenup in the system
Greenup is at Ohio River mile 341, about five miles below the town that gives it its name. USACE navigation charts and district pages place the project squarely between Meldahl pool upstream and the Robert C. Byrd pool downstream. If you are studying traffic or pool hydraulics, start with the Corps’ Greenup page, the Huntington District water-management dashboard, and the federal navigation charts for this reach.
Sources and further reading
U.S. Army Corps of Engineers, Greenup O&M Manual excerpts with construction dates, acceptance, lock sizes, gates, pool and costs through June 30, 1963. Water Data
USACE Great Lakes and Ohio River Division, Greenup project page (overview, replacements of Ohio River L&D 27–30 and Big Sandy No. 1, authority and cost notes). LRD Army Corps
USACE Water Data portal, Greenup project overview and Huntington District river operations context. Water Data
USACE news release and coverage of 2016 main-lock miter gate replacement. Army+1
Federal Register notice, March 8, 2024, acknowledging tendered application for a new major FERC license for the Greenup Hydroelectric Project, P-2614-042. GovInfo
City of Hamilton, Greenup Licensing hub and investor profile (license history, ownership shares, 1982 in-service and typical generation). City of Hamilton, OH+1
American Municipal Power, Greenup Hydroelectric Project summary. American Municipal Power
USGS monitoring site “Ohio River at Greenup Dam near Greenup, KY” (station 03216600). USGS Water Data
NOAA National Water Prediction Service gauge GNUK2. National Water Prediction Service
USACE Ohio River Navigation Charts, Greenup pool. GovInfo
USACE Planning Community Toolbox, Chief of Engineers Interim Report on J. T. Myers and Greenup (ORMSS). Planning Community Toolbox
Public Law 106-541, Water Resources Development Act of 2000, authorizing Greenup auxiliary-lock extension. GovInfo