Benson Dam Reservoir Report
Nearby: Sargent Irrigation Dam R. Hanson Dam
Last Updated: December 13, 2025
Benson Dam, located in Tripp, South Dakota, on Willow Creek, is a privately owned structure with a low hazard potential and a height of 35 feet.
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Summary
Completed in 1977, the dam has a storage capacity of 2900 acre-feet and serves the primary purpose of water resource management in the region. The dam is state-regulated and undergoes regular inspections, with the last recorded inspection date in October 1983.
With a drainage area of 78 square miles and a maximum discharge of 6000 cubic feet per second, Benson Dam plays a crucial role in flood control and water supply management in the area. While the dam's condition is currently rated as "Not Rated," it continues to be a vital piece of infrastructure for the community. The dam's emergency action plan status, risk assessment, and inundation maps remain undisclosed, but the structure is equipped with necessary safety measures to ensure public safety in case of emergencies.
Year Completed |
1977 |
Dam Length |
700 |
Dam Height |
35 |
River Or Stream |
WILLOW CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
35 |
Drainage Area |
78 |
Nid Storage |
2900 |
Hazard Potential |
Low |
Nid Height |
35 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Keya Paha R Near Keyapaha Sd
|
33cfs |
Keya Paha R At Wewela Sd
|
54cfs |
Niobrara River Near Sparks
|
934cfs |
Long Pine Creek Near Riverview
|
188cfs |
Niobrara River At Mariaville
|
1530cfs |
Little White R Near Rosebud Sd
|
96cfs |
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.
Benson Dam