Mollison Dam Reservoir Report
Nearby: Norman Nystrom Frank Hayes
Last Updated: December 7, 2025
Mollison Dam, located in Hughes County, South Dakota, is a privately owned structure designed by the USDA NRCS and completed in 2000.
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Summary
Situated on TR Medicine Creek, this earth-type dam stands at a height of 32 feet and has a storage capacity of 140 acre-feet. With a low hazard potential and a moderate risk rating, the dam has a spillway width of 100 feet and a maximum discharge of 1350 cubic feet per second.
Despite being state-regulated and permitted, Mollison Dam's condition assessment is currently listed as "Not Rated," with no recent inspection data available. The dam has not been modified over the years and does not have a designated emergency action plan. While it serves a primary purpose not specified in the data, the dam's risk management measures and inundation maps status remain undisclosed. With its strategic location and importance in water resource management, Mollison Dam presents an intriguing subject for water resource and climate enthusiasts to explore further.
Year Completed |
2000 |
Dam Length |
226 |
Dam Height |
32 |
River Or Stream |
TR MEDICINE CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
32 |
Drainage Area |
3 |
Nid Storage |
140 |
Outlet Gates |
None |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
32 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Bad R Near Fort Pierre Sd
|
7cfs |
White R Near Oacoma Sd
|
105cfs |
White River Near White River
|
42cfs |
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.
Mollison Dam