Alexander Dam is an earth dam located in Sully County, South Dakota, built in 1976. It carries a Low hazard potential classification.
Dam profile
NID height · 38 ft38 ft tall and 870 ft long, taller than 84% 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 Alexander Dam
The primary purpose of Alexander Dam is fish and wildlife pond. The dam creates habitat for fish and wildlife, supporting local ecosystems and potentially serving conservation goals. The dam is owned by Rocky Alexander (private). It impounds the Tr-mail Shack Creek.
The dam stands 38 feet tall and stretches 870 feet across, and has a maximum storage capacity of 1,150 acre-feet. Completed in 1976, the structure is 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.
At 38 feet, this dam is taller than 84% of dams nationwide.
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Location
| State | South Dakota |
| County | Sully |
| Nearest City | None |
| River/Stream | Tr-mail Shack Creek |
| Coordinates | 44.69855, -100.56315 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 38 ft |
| Dam Height | 38 ft |
| Dam Length | 870 ft |
| Year Completed | 1976 (50 years old) |
Storage & Hydraulics
| NID Storage | 1,150 acre-ft |
| Max Storage | 1,150 acre-ft |
| Normal Storage | 890 acre-ft |
| Max Discharge | 2,080 cfs |
Ownership & Safety
| Purpose | Fish and Wildlife Pond |
| Owner | Rocky Alexander |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | SD02373 |
| Federal ID | SD02373 |
| More Info | State Dam Safety Program |