Lagrange Lock And Dam
Lagrange Lock And Dam is a concrete dam located in Brown County, Illinois, built in 1939. It carries a Significant hazard potential classification.
About Lagrange Lock And Dam
The primary purpose of Lagrange 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 - Rock Island District (federal). It impounds the Illinois River near Meredosia.
The dam stands 21 feet tall and stretches 676 feet across, has a maximum storage capacity of 55,000 acre-feet, and collects water from a drainage area of 25,648 square miles. Completed in 1939, 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 07/07/2022.
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Location
| State | Illinois |
| County | Brown |
| Nearest City | Meredosia |
| River/Stream | Illinois River |
| Coordinates | 39.94040, -90.53430 |
Physical Characteristics
| Dam Type | Concrete |
| NID Height | 21 ft |
| Dam Length | 676 ft |
| Year Completed | 1939 (87 years old) |
Storage & Hydraulics
| NID Storage | 55,000 acre-ft |
| Max Storage | 55,000 acre-ft |
| Drainage Area | 25,648 sq mi |
| Max Discharge | 156,000 cfs |
| Spillway Type | None |
Ownership & Safety
| Purpose | Navigation |
| Owner | USACE - Rock Island District |
| Owner Type | Federal |
| Hazard Classification | Significant |
| Condition Assessment | Not Available |
| Last Inspection | 07/07/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | IL01015 |
| Federal ID | IL01015 |
| More Info | State Dam Safety Program |