Allen
Allen is an earth dam located in Bennett County, South Dakota, built in 1961. It carries a High hazard potential classification and has a unsatisfactory condition assessment.
About Allen
The primary purpose of Allen is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Bia (federal). It impounds the No Flesh Creek -tr.
The dam stands 24 feet tall and stretches 370 feet across, creates a reservoir covering 19 acres, has a maximum storage capacity of 359 acre-feet, and collects water from a drainage area of 12 square miles. Completed in 1961, 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. Its condition is rated unsatisfactory, indicating serious safety deficiencies exist that require immediate attention or remedial action. An emergency action plan is in place for this dam. The most recent inspection on record was 08/25/2020.
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 South 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 | South Dakota |
| County | Bennett |
| Nearest City | None |
| River/Stream | No Flesh Creek -tr |
| Coordinates | 43.33329, -102.03880 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 24 ft |
| Dam Height | 24 ft |
| Dam Length | 370 ft |
| Year Completed | 1961 (65 years old) |
Storage & Hydraulics
| NID Storage | 359 acre-ft |
| Max Storage | 359 acre-ft |
| Normal Storage | 132 acre-ft |
| Surface Area | 19 acres |
| Drainage Area | 12 sq mi |
| Max Discharge | 5,121 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | BIA |
| Owner Type | Federal |
| Hazard Classification | High |
| Condition Assessment | Unsatisfactory |
| Last Inspection | 08/25/2020 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | SD00981 |
| Federal ID | SD00981 |
| More Info | State Dam Safety Program |