Rock Cowan No.3 is an earth dam located in Dewey County, South Dakota, built in 1950. It carries a Low hazard potential classification.
Dam profile
NID height · 22 ft22 ft tall and 550 ft long. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic embankment section and the water level is illustrative.
About Rock Cowan No.3
The primary purpose of Rock Cowan No.3 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 Rock Cowan (private). It impounds the Tr-moreau.
The dam stands 22 feet tall and stretches 550 feet across, and has a maximum storage capacity of 280 acre-feet. Completed in 1950, 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.
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Location
| State | South Dakota |
| County | Dewey |
| Nearest City | None |
| River/Stream | Tr-moreau |
| Coordinates | 45.09499, -101.44666 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 22 ft |
| Dam Height | 22 ft |
| Dam Length | 550 ft |
| Year Completed | 1950 (76 years old) |
Storage & Hydraulics
| NID Storage | 280 acre-ft |
| Max Storage | 280 acre-ft |
| Normal Storage | 160 acre-ft |
| Max Discharge | 2,150 cfs |
Ownership & Safety
| Purpose | Fire Protection, Stock, Or Small Fish Pond |
| Owner | Rock Cowan |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | SD00351 |
| Federal ID | SD00351 |
| More Info | State Dam Safety Program |