Woolhizer Dam Reservoir Report
Nearby: Blomstrom Dam Richey Dam
Last Updated: December 13, 2025
Woolhizer Dam, located in Tripp, South Dakota, was completed in 1935 and stands at a height of 30 feet with a length of 520 feet.
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Summary
The dam is primarily used for water storage on the TR-KEYAPAHA RIVER, with a capacity of 450 acre-feet and a normal storage level of 160 acre-feet. Despite its age, the dam is considered to have a low hazard potential and is currently rated as "Not Rated" in terms of condition assessment.
Operated by a private entity, Woolhizer Dam is regulated by the South Dakota Department of Environment and Natural Resources (DENR) and undergoes regular state inspections, permitting, and enforcement. The dam's primary purpose and specific design features are not specified, but it is classified as an Earth-type dam. Additionally, the dam falls under the jurisdiction of the St. Paul District of the US Army Corps of Engineers, and its emergency action plan status and risk management measures are currently unknown.
Despite lacking detailed information on its current condition and emergency preparedness, Woolhizer Dam remains a key feature in the water resource infrastructure of South Dakota. With its historical significance and role in regulating water flow on the TR-KEYAPAHA RIVER, the dam is of interest to water resource and climate enthusiasts seeking to understand the impact of aging infrastructure on water management in the region.
Year Completed |
1935 |
Dam Length |
520 |
Dam Height |
30 |
River Or Stream |
TR-KEYAPAHA RIVER |
Primary Dam Type |
Earth |
Hydraulic Height |
30 |
Nid Storage |
450 |
Hazard Potential |
Low |
Nid Height |
30 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Keya Paha R At Wewela Sd
|
54cfs |
Keya Paha R Near Keyapaha Sd
|
33cfs |
Long Pine Creek Near Riverview
|
191cfs |
Niobrara River At Mariaville
|
1650cfs |
Niobrara River Near Sparks
|
969cfs |
Platte Creek Near Platte
|
3cfs |
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.
Woolhizer Dam