J. Willey Reservoir Report
Nearby: R. Lemler Bartels Dam
Last Updated: December 12, 2025
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Summary
Willey is a private dam located in Potter, South Dakota, along the TR-Cheyenne Creek. Built in 1948, this earth dam stands at 16 feet high and spans 490 feet in length, with a storage capacity of 116 acre-feet. The dam is regulated and inspected by the South Dakota Department of Agriculture and Natural Resources, ensuring its safety and compliance with state regulations.
Despite its low hazard potential, J. Willey poses a moderate risk level, as assessed by the authorities. The dam features an uncontrolled spillway with a width of 200 feet, capable of handling a maximum discharge of 1300 cubic feet per second. With a drainage area of 3 square miles, J. Willey serves as a crucial water resource for the local community and contributes to the management of water flow in the region.
Managed by the Natural Resources Conservation Service, J. Willey plays a vital role in water resource management and climate resilience in South Dakota. With its history dating back over seven decades, this dam continues to uphold its purpose of providing water storage and flood control, all while adhering to strict regulatory standards to ensure the safety of the surrounding area and its inhabitants.
Year Completed |
1948 |
Dam Length |
490 |
Dam Height |
16 |
River Or Stream |
TR-CHEYENNE CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
16 |
Drainage Area |
3 |
Nid Storage |
116 |
Hazard Potential |
Low |
Nid Height |
16 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Moreau R Near Whitehorse Sd
|
35cfs |
Oak Cr Near Wakpala Sd
|
10cfs |
Grand R At Little Eagle Sd
|
47cfs |
Bad R Near Fort Pierre Sd
|
7cfs |
Dam Data Reference
Condition Assessment
SatisfactoryNo existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.
Hazard Potential Classification
HighDams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.
J. Willey