Sentinel Detention Dam is a gravity dam located in Phillips County, Montana, built in 1969. It carries a Low hazard potential classification and has a fair condition assessment.
Dam profile
NID height · 33 ft33 ft tall and 491 ft long, taller than 76% of U.S. dams with a recorded height. 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 Sentinel Detention Dam
The primary purpose of Sentinel Detention Dam is fire protection, stock, or small fish pond. The dam maintains a small impoundment used for fire suppression, livestock watering, or as a fish pond. The dam is owned by Doi BLM (federal). It impounds the Ck Ck./missouri River near Fort Peck.
The dam stands 33 feet tall and stretches 491 feet across, creates a reservoir covering 29 acres, has a maximum storage capacity of 256 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1969, 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 fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. The most recent inspection on record was 10/24/2017.
At 33 feet, this dam is taller than 76% of dams nationwide.
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Location
| State | Montana |
| County | Phillips |
| Nearest City | Fort Peck |
| River/Stream | Ck Ck./missouri River |
| Coordinates | 47.76095, -108.42964 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 33 ft |
| Dam Length | 491 ft |
| Year Completed | 1969 (57 years old) |
Storage & Hydraulics
| NID Storage | 256 acre-ft |
| Max Storage | 256 acre-ft |
| Normal Storage | 186 acre-ft |
| Surface Area | 29 acres |
| Drainage Area | 1 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Fire Protection, Stock, Or Small Fish Pond |
| Owner | Doi BLM |
| Owner Type | Federal |
| Hazard Classification | Low |
| Condition Assessment | Fair |
| Last Inspection | 10/24/2017 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | MT00718 |
| Federal ID | MT00718 |
| More Info | State Dam Safety Program |