Sheridan Lake Reservoir Report

Last Updated: December 5, 2025

Sheridan Lake, located in Pennington, South Dakota, is a Federal-owned water resource managed by the Forest Service for recreation purposes.


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Summary

This Earth dam, completed in 1939, stands at a height of 134 feet and has a storage capacity of 22,043 acre-feet. The lake, fed by Spring Creek and covering a surface area of 0 acres, offers opportunities for fish and wildlife activities as well as recreational pursuits.

With a maximum discharge of 24,170 cubic feet per second and a controlled spillway width of 30 feet, Sheridan Lake poses a high hazard potential but is currently rated as in "Not Rated" condition. Despite its high risk assessment, the lake remains a popular destination for visitors seeking outdoor adventures in the scenic surroundings. The emergency action plan status and risk management measures for Sheridan Lake are currently not specified, indicating a need for further evaluation and planning to ensure the safety of the area.

Overall, Sheridan Lake presents a mix of natural beauty and potential risks, making it an intriguing destination for water resource and climate enthusiasts. As a key site managed by the Forest Service in South Dakota, the lake provides a valuable recreational opportunity while also requiring careful monitoring and management to address its high hazard potential. With its rich history and diverse offerings, Sheridan Lake continues to attract visitors looking to explore the unique ecosystem and enjoy the outdoor activities available in this Federal-owned water resource.

Year Completed

1939

Dam Length

850

Dam Height

134

River Or Stream

SPRING CREEK

Primary Dam Type

Earth

Hydraulic Height

116

Drainage Area

148

Nid Storage

22043

Structural Height

126

Outlet Gates

Roller

Hazard Potential

High

Nid Height

134
       
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.