Mirrow Lake Dam Reservoir Report

Last Updated: December 5, 2025

Mirrow Lake Dam, also known as Oneal Wynn Lake Dam, is a privately owned structure located in Irwinville, Turner, Georgia.


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Summary

Built in 1975, this earth dam stands at a height of 18.4 feet and serves primarily for recreational purposes, offering a surface area of 11.5 acres and a normal storage capacity of 79 acre-feet. With a low hazard potential and a moderate risk assessment rating of 3, the dam has not been inspected since January 2015.

Managed by the Jacksonville District of the US Army Corps of Engineers, Mirrow Lake Dam features an uncontrolled spillway type and outlet gates. While it is not state-regulated, the dam is subject to state inspection and falls within the jurisdiction of Georgia. The dam's designer is listed as SCS, and it is associated with no other structures. Despite its condition being rated as "Not Rated," the dam's moderate risk level indicates the need for ongoing monitoring and potentially updated emergency action plans to ensure the safety of surrounding areas and water resources.

Year Completed

1975

Dam Length

515

Dam Height

18.4

River Or Stream

UNKNOWN

Primary Dam Type

Earth

Surface Area

11.5

Hydraulic Height

17.3

Drainage Area

118

Nid Storage

123

Outlet Gates

Uncontrolled

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

18
       
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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.