Garrison Dam - Williston Levee
Garrison Dam - Williston Levee is an earth dam located in Williams County, North Dakota, built in 1953. It carries a High hazard potential classification.
About Garrison Dam - Williston Levee
The primary purpose of Garrison Dam - Williston Levee is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by Usace - Omaha District (federal). It impounds the Missouri River near Williston.
The dam stands 28 feet tall and stretches 44,500 feet across, creates a reservoir covering 133,000 acres, has a maximum storage capacity of 26,000,000 acre-feet, and collects water from a drainage area of 180,940 square miles. Completed in 1953, the structure is well into its service life at over 50 years old.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. An emergency action plan is in place for this dam. The most recent inspection on record was 06/15/2018. That was 7 years ago, which is on the longer end for a high-hazard structure.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The North Dakota dam safety program can provide more specific information about emergency planning for this structure.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | North Dakota |
| County | Williams |
| Nearest City | Williston |
| River/Stream | Missouri River |
| Coordinates | 48.12928, -103.63576 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 28 ft |
| Dam Length | 44,500 ft |
| Year Completed | 1953 (73 years old) |
Storage & Hydraulics
| NID Storage | 26,000,000 acre-ft |
| Max Storage | 26,000,000 acre-ft |
| Normal Storage | 18,500,000 acre-ft |
| Surface Area | 133,000 acres |
| Drainage Area | 180,940 sq mi |
| Spillway Type | None |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | USACE - Omaha District |
| Owner Type | Federal |
| Hazard Classification | High |
| Condition Assessment | Not Available |
| Last Inspection | 06/15/2018 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | ND00145 |
| Federal ID | ND00145S001 |
| More Info | State Dam Safety Program |