Iverson Retention Dam
Iverson Retention Dam is a gravity dam located in Petroleum County, Montana, built in 1968. It carries a Low hazard potential classification and has a poor condition assessment.
About Iverson Retention Dam
The primary purpose of Iverson Retention Dam 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 Doi Blm (federal). It impounds the Flatwillow Ck./musselshell Riv near Mosby.
The dam stands 22 feet tall and stretches 306 feet across, creates a reservoir covering 11 acres, and has a maximum storage capacity of 66 acre-feet. Completed in 1968, the structure is well into its service life at over 50 years old.
This dam has a low hazard potential classification, meaning that failure would cause minimal damage, limited primarily to the dam owner's property, with no expected loss of life. Its condition is rated poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. The most recent inspection on record was 08/09/2010. That was over 15 years ago.
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Location
| State | Montana |
| County | Petroleum |
| Nearest City | Mosby |
| River/Stream | Flatwillow Ck./musselshell Riv |
| Coordinates | 46.77997, -108.52113 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 22 ft |
| Dam Length | 306 ft |
| Year Completed | 1968 (58 years old) |
Storage & Hydraulics
| NID Storage | 66 acre-ft |
| Max Storage | 66 acre-ft |
| Surface Area | 11 acres |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | DOI BLM |
| Owner Type | Federal |
| Hazard Classification | Low |
| Condition Assessment | Poor |
| Last Inspection | 08/09/2010 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | MT03079 |
| Federal ID | MT03079 |
| More Info | State Dam Safety Program |