Mississippi River Lock And Dam 9
Mississippi River Lock And Dam 9 is a concrete dam located in Allamakee County, Wisconsin, built in 1937. It carries a Significant hazard potential classification.
About Mississippi River Lock And Dam 9
The primary purpose of Mississippi River Lock And Dam 9 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 River near Prairie Du Chien.
The dam stands 46 feet tall and stretches 9,087 feet across, creates a reservoir covering 29,125 acres, has a maximum storage capacity of 470,000 acre-feet, and collects water from a drainage area of 66,610 square miles. Completed in 1937, 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 09/18/2019.
At 46 feet, this dam is taller than 91% of dams nationwide.
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Location
| State | Wisconsin |
| County | Allamakee |
| Nearest City | Prairie Du Chien |
| River/Stream | Mississippi River |
| Coordinates | 43.21223, -91.10015 |
Physical Characteristics
| Dam Type | Concrete |
| NID Height | 46 ft |
| Dam Height | 18 ft |
| Dam Length | 9,087 ft |
| Year Completed | 1937 (89 years old) |
Storage & Hydraulics
| NID Storage | 470,000 acre-ft |
| Max Storage | 470,000 acre-ft |
| Normal Storage | 197,000 acre-ft |
| Surface Area | 29,125 acres |
| Drainage Area | 66,610 sq mi |
| Max Discharge | 278,000 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Navigation |
| Owner | USACE - St. Paul District |
| Owner Type | Federal |
| Hazard Classification | Significant |
| Condition Assessment | Not Available |
| Last Inspection | 09/18/2019 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | WI00733 |
| Federal ID | WI00733 |
| More Info | State Dam Safety Program |