Mercer Number 1 Reservoir Report
Nearby: Carl Albright Heintz Number 1
Last Updated: December 12, 2025
Mercer Number 1 is a privately owned dam located in Hughes County, South Dakota, along the TR-MEDICINE KNOLL CREEK.
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Summary
Built in 1950, this earth dam stands at a height of 9 feet and has a maximum storage capacity of 53 acre-feet. The dam serves a low hazard potential and is currently in a "Not Rated" condition assessment status.
Managed by the Natural Resources Conservation Service, Mercer Number 1 is regulated by the South Dakota Department of Environment and Natural Resources. With state permitting, inspection, and enforcement in place, the dam has been designed for water resource management purposes. Despite its age, the dam has shown no significant modifications or risk assessment measures to date.
Given its location and purpose, Mercer Number 1 plays a crucial role in the local water resource infrastructure. While it currently poses a low hazard potential, ongoing monitoring and maintenance will be essential to ensure the safety and effectiveness of this important water management structure in the years to come.
Year Completed |
1950 |
Dam Length |
475 |
Dam Height |
9 |
River Or Stream |
TR-MEDICINE KNOLL CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
7 |
Nid Storage |
53 |
Hazard Potential |
Low |
Nid Height |
9 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Bad R Near Fort Pierre Sd
|
7cfs |
White R Near Oacoma Sd
|
105cfs |
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.
Mercer Number 1