Koskan is an earth dam located in Mellette County, South Dakota, built in 1956. It carries a Low hazard potential classification.
Dam profile
NID height · 22 ft22 ft tall and 342 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 Koskan
The primary purpose of Koskan 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 Koskan (private). It impounds the Tr. Big White Offstream.
The dam stands 22 feet tall and stretches 342 feet across, and has a maximum storage capacity of 55 acre-feet. Completed in 1956, 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.
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Location
| State | South Dakota |
| County | Mellette |
| Nearest City | None |
| River/Stream | Tr. Big White Offstream |
| Coordinates | 43.58034, -100.37819 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 22 ft |
| Dam Height | 22 ft |
| Dam Length | 342 ft |
| Year Completed | 1956 (70 years old) |
Storage & Hydraulics
| NID Storage | 55 acre-ft |
| Max Storage | 55 acre-ft |
| Normal Storage | 47 acre-ft |
| Max Discharge | 100 cfs |
Ownership & Safety
| Purpose | Fire Protection, Stock, Or Small Fish Pond |
| Owner | Koskan |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | SD01535 |
| Federal ID | SD01535 |
| More Info | State Dam Safety Program |