Br-43 Retention Dam is a gravity dam located in Blaine County, Montana, built in 1936. It carries a Low hazard potential classification.
Dam profile
NID height · 21 ft21 ft tall and 385 ft long. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic concrete gravity section and the water level is illustrative.
About Br-43 Retention Dam
The primary purpose of Br-43 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 Thirtymile Ck./milk River near Dodson.
The dam stands 21 feet tall and stretches 385 feet across, creates a reservoir covering 13 acres, has a maximum storage capacity of 53 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1936, the structure is well-established, with more than 75 years of service.
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. The most recent inspection on record was 09/01/2017.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Montana |
| County | Blaine |
| Nearest City | Dodson |
| River/Stream | Thirtymile Ck./milk River |
| Coordinates | 48.60589, -108.78509 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 21 ft |
| Dam Length | 385 ft |
| Year Completed | 1936 (90 years old) |
Storage & Hydraulics
| NID Storage | 53 acre-ft |
| Max Storage | 53 acre-ft |
| Normal Storage | 53 acre-ft |
| Surface Area | 13 acres |
| Drainage Area | 1 sq mi |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | Doi BLM |
| Owner Type | Federal |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Last Inspection | 09/01/2017 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | MT00797 |
| Federal ID | MT00797 |
| More Info | State Dam Safety Program |