Sub-Penitentiary Lake Reservoir Report

Last Updated: December 6, 2025

Sub-Penitentiary Lake, also known as Bluestem Lake, is a captivating water resource nestled in Atoka, Oklahoma.


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Summary

Owned by the state and regulated by the Oklahoma Water Resources Board, this recreational gem sits on Elm Creek and offers a tranquil escape in the city of Flora. Completed in 1940, this Earth dam stands at a height of 40 feet and has a storage capacity of 933 acre-feet, making it an ideal spot for outdoor enthusiasts looking for a peaceful retreat.

With a surface area of 90 acres and a maximum discharge of 1934 cubic feet per second, Sub-Penitentiary Lake offers a balance of serenity and adventure for visitors. The controlled spillway and valve outlet gates ensure safety and environmental conservation, while the low hazard potential and very high risk assessment rating speak to the careful monitoring and management practices in place. Despite not being rated for condition assessment, this lake is a haven for those seeking a peaceful haven in the heart of Oklahoma.

Whether you're a climate enthusiast or a water resource aficionado, Sub-Penitentiary Lake is a hidden gem waiting to be explored. With its picturesque setting, recreational opportunities, and state-regulated facilities, this Earth dam offers a unique blend of relaxation and adventure for all who visit. So pack your bags, grab your gear, and embark on a journey to this enchanting oasis in Atoka, Oklahoma.

Year Completed

1940

Dam Length

795

Dam Height

40

River Or Stream

ELM CRK.

Primary Dam Type

Earth

Surface Area

90

Hydraulic Height

36

Nid Storage

933

Structural Height

40

Outlet Gates

Valve - 1

Hazard Potential

Low

Foundations

Soil

Nid Height

40
       
Seasonal Comparison

Weather Forecast

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.