Moon Lake Dam Reservoir Report

Last Updated: December 5, 2025

Moon Lake Dam, located in Henry, Georgia, is a recreational dam with a primary purpose of providing leisure activities for water resource and climate enthusiasts.


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Summary

Managed by the local government, the dam stands at a height of 26 feet and spans a length of 615 feet along the Long Branch river. Despite its significant storage capacity of 207 acre-feet, the dam is classified as having a high hazard potential and a poor condition assessment, signaling potential risks that need to be addressed.

The dam, constructed with an earth core and buttress design, features uncontrolled spillways and outlets, posing challenges in managing water flow during high-risk scenarios. While the dam is regulated, permitted, and inspected by the Georgia Safe Dams Program, the last inspection in February 2019 highlighted the need for maintenance and improvement. With a moderate risk assessment score of 3, Moon Lake Dam underscores the importance of implementing effective risk management measures to ensure the safety of the surrounding community and environment.

As a focal point for recreation in the area, Moon Lake Dam serves as a reminder of the delicate balance between human enjoyment and natural resource conservation. With its location in a high-risk area and a history of poor condition, the dam presents an opportunity for stakeholders to come together to prioritize safety, maintenance, and sustainable management practices to safeguard the dam's integrity for future generations of water enthusiasts and climate advocates.

Dam Length

615

Dam Height

26

River Or Stream

LONG BRANCH

Primary Dam Type

Earth

Surface Area

12

Nid Storage

207

Outlet Gates

Uncontrolled

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

26
       
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.