Roscoe Riggle Reservoir Report

Last Updated: December 6, 2025

Roscoe Riggle, a privately owned earth dam located in Stanley, South Dakota, was completed in 1958 and is regulated by the South Dakota Department of Environment and Natural Resources.


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Summary

Standing at a height of 15 feet and with a length of 500 feet, this dam serves the primary purpose of water resource management along the Tributary Plum Creek. Managed by the Natural Resources Conservation Service, the dam has a storage capacity of 69 acre-feet and a low hazard potential.

Despite its age, Roscoe Riggle has not been rated for its condition assessment, and its emergency action plan status remains unclear. With a maximum discharge capacity of 2024 cubic feet per second, the dam plays a crucial role in mitigating flood risk and ensuring water supply reliability in the region. As climate change continues to impact water resources, infrastructure like Roscoe Riggle will be essential in adapting to changing hydrological conditions and safeguarding communities from extreme weather events.

Year Completed

1958

Dam Length

500

Dam Height

15

River Or Stream

TRIB. PLUM CREEK

Primary Dam Type

Earth

Hydraulic Height

15

Nid Storage

69

Hazard Potential

Low

Nid Height

15
       
Seasonal Comparison

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Dam Data Reference

Condition Assessment

Satisfactory
No 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

High
Dams 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.