J.E. Sheehan Estate #2 Reservoir Report
Last Updated: December 13, 2025
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Summary
Sheehan Estate #2 is a privately owned earth dam located in Stanley, South Dakota, along Tributary Agency Creek. Constructed in 1957 by the Natural Resources Conservation Service, this dam stands at a height of 28 feet and spans 550 feet in length. With a storage capacity of 85 acre-feet, it serves as a crucial water resource for the surrounding area, with a normal storage level of 36 acre-feet.
Despite being classified as a low hazard potential structure, J.E. Sheehan Estate #2 is regulated by the South Dakota Department of Environment and Natural Resources (DENR), ensuring that it meets state inspection, enforcement, and permitting requirements. While the dam's condition is currently rated as "Not Rated," indicating a lack of recent assessment, its emergency action plan status and risk management measures remain unspecified. Additionally, the dam's maximum discharge capacity of 2250 cubic feet per second highlights its importance in flood control and water management in the region.
As a key infrastructure for water storage and management in South Dakota, J.E. Sheehan Estate #2 plays a vital role in safeguarding against potential risks and emergencies. With its location in a rural area and limited associated structures, this dam serves as a testament to the importance of maintaining and regulating our water resources to ensure the sustainability and resilience of our communities in the face of changing climate conditions.
Year Completed |
1957 |
Dam Length |
550 |
Dam Height |
28 |
River Or Stream |
TRIB. AGENCY CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
28 |
Nid Storage |
85 |
Hazard Potential |
Low |
Nid Height |
28 |
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.
J.E. Sheehan Estate #2