Mississippi River Lock and Dam 5a - Winona Levee is a concrete dam located in Winona County, Minnesota, built in 1936. It carries a Significant hazard potential classification.
Dam profile
NID height · 46 ft46 ft tall and 21,520 ft long, taller than 91% 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 Mississippi River Lock and Dam 5a - Winona Levee
The primary purpose of Mississippi River Lock and Dam 5a - Winona Levee 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 - St. Paul District (federal). It impounds the Mississippi near Winona.
The dam stands 46 feet tall and stretches 21,520 feet across, creates a reservoir covering 7,000 acres, has a maximum storage capacity of 260,000 acre-feet, and collects water from a drainage area of 59,105 square miles. Completed in 1936, the structure is well-established, with more than 75 years of service.
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 05/03/2017.
At 46 feet, this dam is taller than 91% of dams nationwide.
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Location
| State | Minnesota |
| County | Winona |
| Nearest City | Winona |
| River/Stream | Mississippi |
| Coordinates | 44.09220, -91.72020 |
Physical Characteristics
| Dam Type | Concrete |
| NID Height | 46 ft |
| Dam Height | 17 ft |
| Dam Length | 21,520 ft |
| Year Completed | 1936 (90 years old) |
Storage & Hydraulics
| NID Storage | 260,000 acre-ft |
| Max Storage | 260,000 acre-ft |
| Normal Storage | 27,700 acre-ft |
| Surface Area | 7,000 acres |
| Drainage Area | 59,105 sq mi |
| Max Discharge | 268,000 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Navigation |
| Owner | USACE - St. Paul District |
| Owner Type | Federal |
| Hazard Classification | Significant |
| Condition Assessment | Not assessed |
| Last Inspection | 05/03/2017 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MN00588 |
| Federal ID | MN00588S001 |
| More Info | State Dam Safety Program |