Iwan O.m. Number 1 is an earth dam located in Mellette County, South Dakota, built in 1970. It carries a Low hazard potential classification.
Dam profile
NID height · 26 ft26 ft tall and 300 ft long, taller than 55% 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 embankment section and the water level is illustrative.
About Iwan O.m. Number 1
The primary purpose of Iwan O.m. Number 1 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 O.m. Iwan (private). It impounds the Trib of White River.
The dam stands 26 feet tall and stretches 300 feet across, and has a maximum storage capacity of 45 acre-feet. Completed in 1970, 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 | Trib of White River |
| Coordinates | 43.82166, -101.08499 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 26 ft |
| Dam Height | 26 ft |
| Dam Length | 300 ft |
| Year Completed | 1970 (56 years old) |
Storage & Hydraulics
| NID Storage | 45 acre-ft |
| Max Storage | 45 acre-ft |
| Normal Storage | 30 acre-ft |
| Max Discharge | 2,100 cfs |
Ownership & Safety
| Purpose | Fire Protection, Stock, Or Small Fish Pond |
| Owner | O.m. Iwan |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | SD01268 |
| Federal ID | SD01268 |
| More Info | State Dam Safety Program |