Demopolis Lock and Dam is a gravity dam located in Marengo County, Alabama, built in 1955. It carries a Significant hazard potential classification.
Dam profile
NID height · 63 ft63 ft tall and 1,770 ft long, taller than 95% of U.S. dams with a recorded height. Height is drawn to scale against a ten-story building, about 100 ft; the profile is a generic concrete gravity section and the water level is illustrative.
About Demopolis Lock and Dam
The primary purpose of Demopolis Lock and Dam is navigation. The dam maintains water levels sufficient for boat and barge traffic, supporting commercial or recreational navigation on the waterway. The dam is owned by USACE - Mobile District (federal). It impounds the Tombigbee River near Demopolis.
The dam stands 63 feet tall and stretches 1,770 feet across, creates a reservoir covering 10,000 acres, has a maximum storage capacity of 150,000 acre-feet, and collects water from a drainage area of 15,385 square miles. Completed in 1955, the structure is well into its service life at over 50 years old.
This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. An emergency action plan is in place for this dam. The most recent inspection on record was 06/27/2024.
At 63 feet, this dam is taller than 95% of all dams in the United States.
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Location
| State | Alabama |
| County | Marengo |
| Nearest City | Demopolis |
| River/Stream | Tombigbee River |
| Coordinates | 32.52077, -87.87907 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 63 ft |
| Dam Length | 1,770 ft |
| Year Completed | 1955 (71 years old) |
Storage & Hydraulics
| NID Storage | 150,000 acre-ft |
| Max Storage | 150,000 acre-ft |
| Normal Storage | 120,000 acre-ft |
| Surface Area | 10,000 acres |
| Drainage Area | 15,385 sq mi |
| Max Discharge | 88,000 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Navigation |
| Owner | USACE - Mobile District |
| Owner Type | Federal |
| Hazard Classification | Significant |
| Condition Assessment | Not assessed |
| Last Inspection | 06/27/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | AL01430 |
| Federal ID | AL01430 |
| More Info | ASDSO on Alabama (no state dam safety program) |