Mississippi River Locks And Dam 27
Mississippi River Locks And Dam 27 is a rockfill dam located in Madison County, Missouri, built in 1962. It carries a Significant hazard potential classification.
About Mississippi River Locks And Dam 27
The primary purpose of Mississippi River Locks And Dam 27 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. Louis District (federal). It impounds the Mississippi River near Granite City.
The dam stands 25 feet tall and stretches 3,240 feet across, and has a storage capacity of 50 acre-feet. Completed in 1962, 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 05/14/2024.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Missouri |
| County | Madison |
| Nearest City | Granite City |
| River/Stream | Mississippi River |
| Coordinates | 38.70293, -90.18096 |
Physical Characteristics
| Dam Type | Rockfill |
| NID Height | 25 ft |
| Dam Height | 25 ft |
| Dam Length | 3,240 ft |
| Year Completed | 1962 (64 years old) |
Storage & Hydraulics
| NID Storage | 50 acre-ft |
| Normal Storage | 50 acre-ft |
| Max Discharge | 1,300,000 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Navigation |
| Owner | USACE - St. Louis District |
| Owner Type | Federal |
| Hazard Classification | Significant |
| Condition Assessment | Not Available |
| Last Inspection | 05/14/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MO10302 |
| Federal ID | MO10302 |
| More Info | State Dam Safety Program |