John Alley
John Alley is an earth dam located in Jackson County, South Dakota, built in 1946. It carries a Low hazard potential classification.
About John Alley
The primary purpose of John Alley 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 Robert Alley (private). It impounds the Tr-black Horse Creek.
The dam stands 16 feet tall and stretches 670 feet across, and has a maximum storage capacity of 128 acre-feet. Completed in 1946, 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 | Jackson |
| Nearest City | None |
| River/Stream | Tr-black Horse Creek |
| Coordinates | 43.50166, -101.64999 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 16 ft |
| Dam Height | 16 ft |
| Dam Length | 670 ft |
| Year Completed | 1946 (80 years old) |
Storage & Hydraulics
| NID Storage | 128 acre-ft |
| Max Storage | 128 acre-ft |
| Normal Storage | 51 acre-ft |
| Max Discharge | 4,840 cfs |
Ownership & Safety
| Purpose | Fire Protection, Stock, Or Small Fish Pond |
| Owner | ROBERT ALLEY |
| Owner Type | Private |
| Hazard Classification | Low |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | SD00742 |
| Federal ID | SD00742 |
| More Info | State Dam Safety Program |