Ivan Mills Reservoir Report
Nearby: Tom Gabbert Floyd Hall
Last Updated: December 6, 2025
Ivan Mills is a privately owned dam located in Perkins, South Dakota, along the TR Moreau River.
°F
°F
mph
Wind
%
Humidity
Summary
Built in 1952, this earth dam stands at 22 feet high and spans 420 feet in length, with a storage capacity of 195 acre-feet. Although it is not associated with any federal agency, the dam is regulated by the South Dakota Department of Environment and Natural Resources (DENR), with state permitting, inspection, and enforcement in place to ensure its safety and compliance.
With a low hazard potential and a current condition assessment of "Not Rated," Ivan Mills is classified as a relatively low-risk structure. While its emergency action plan (EAP) status and risk assessment details are not readily available, the dam does not have any associated locks, spillways, or outlet gates. The dam's location in a sparsely populated area and its lack of federal ownership suggest that it may not be a high priority for extensive monitoring or maintenance, but its importance for local water resources and climate resilience remains vital.
Overall, Ivan Mills represents a piece of South Dakota's water infrastructure history, serving a primarily private purpose in the region. As a dam with state jurisdiction and regulatory oversight, its role in water management on the TR Moreau River highlights the interconnectedness of human-made structures with natural ecosystems and the importance of ongoing monitoring and maintenance for long-term sustainability in the face of changing climate conditions.
Year Completed |
1952 |
Dam Length |
420 |
Dam Height |
22 |
River Or Stream |
TR MOREAU RIVER |
Primary Dam Type |
Earth |
Hydraulic Height |
22 |
Nid Storage |
195 |
Hazard Potential |
Low |
Nid Height |
22 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
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.
Ivan Mills