T.w. Lyman
T.w. Lyman is an earth dam located in Corson County, South Dakota, built in 1940. It carries a Significant hazard potential classification.
About T.w. Lyman
The primary purpose of T.w. Lyman 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 Adolph Hepper (private). It impounds the Tr-oak Creek near Wakpala.
The dam stands 19 feet tall and stretches 600 feet across, and has a maximum storage capacity of 175 acre-feet. Completed in 1940, the structure is well-established, with more than 75 years of service.
This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life.
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Location
| State | South Dakota |
| County | Corson |
| Nearest City | Wakpala |
| River/Stream | Tr-oak Creek |
| Coordinates | 45.91999, -100.77499 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 19 ft |
| Dam Height | 19 ft |
| Dam Length | 600 ft |
| Year Completed | 1940 (86 years old) |
Storage & Hydraulics
| NID Storage | 175 acre-ft |
| Max Storage | 175 acre-ft |
| Normal Storage | 96 acre-ft |
| Max Discharge | 2,100 cfs |
Ownership & Safety
| Purpose | Fire Protection, Stock, Or Small Fish Pond |
| Owner | ADOLPH HEPPER |
| Owner Type | Private |
| Hazard Classification | Significant |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | SD00729 |
| Federal ID | SD00729 |
| More Info | State Dam Safety Program |