H. C. Seymore Est Reservoir Report
Nearby: Rock Cowan No.3 Rock Cowan No.2
Last Updated: February 11, 2026
Located in Dewey, South Dakota, the H.
Summary
C. Seymore Est dam stands as a testament to the importance of water resource management in the region. Completed in 1950, this earth dam has a height of 15 feet and a length of 660 feet, providing a storage capacity of 60 acre-feet. Situated on the TR-MOREAU river, the dam is regulated by the South Dakota Department of Environment and Natural Resources (DENR) and is deemed to have a low hazard potential.
Despite not being currently rated for its condition, the H. C. Seymore Est dam plays a crucial role in water storage and flood control in the area. With a maximum discharge capacity of 4080 cubic feet per second, the dam helps to mitigate the risk of flooding and ensures a stable water supply for the surrounding community. As a private-owned structure, the dam is subject to state inspection, permitting, and enforcement, showcasing the commitment to ensuring its safety and functionality for the benefit of all stakeholders involved.
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Humidity
15-Day Weather Outlook
Year Completed |
1950 |
Dam Length |
660 |
Dam Height |
15 |
River Or Stream |
TR-MOREAU |
Primary Dam Type |
Earth |
Hydraulic Height |
15 |
Nid Storage |
60 |
Hazard Potential |
Low |
Nid Height |
15 |
Seasonal Comparison
5-Day Hourly Forecast Detail
Nearby Streamflow Levels
Moreau R Near Whitehorse Sd
|
35cfs |
Moreau R Near Faith Sd
|
14cfs |
Cheyenne R Near Plainview Sd
|
0cfs |
Grand R At Little Eagle Sd
|
47cfs |
Oak Cr Near Wakpala Sd
|
10cfs |
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.
H. C. Seymore Est