Darby Reservoir Report

Last Updated: December 5, 2025

Darby, also known as Darby Lake Dam, is a federally owned water resource structure located in Charleston, Arkansas.


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Summary

Constructed in 1956 by the US Army, this earth dam stands at a height of 27 feet and serves primarily for water supply purposes, with a storage capacity of 1123 acre-feet. The dam also plays a role in flood risk reduction for the area, with a spillway width of 200 feet that can handle a maximum discharge of 4125 cubic feet per second.

Situated on Tr Prairie Creek, Darby Lake Dam covers a surface area of 150 acres and has a normal storage capacity of 516 acre-feet. Despite its age, the dam's hazard potential is rated as significant, with a moderate risk assessment. While the condition assessment is not available, the dam has undergone inspections with the last one conducted in July 1992. The Emergency Action Plan (EAP) for Darby is dated back to 2008, indicating preparedness in case of any emergencies related to the dam's operation.

Overall, Darby Lake Dam stands as a vital infrastructure for water supply and flood risk management in the region, showcasing the collaboration between the US Army and the Natural Resources Conservation Service in its design and construction. With its historical significance and ongoing operational role, Darby continues to be a key asset in ensuring water resource sustainability and safety in Franklin County, Arkansas.

Year Completed

1956

Dam Length

900

Dam Height

27

River Or Stream

Tr Prairie Creek

Primary Dam Type

Earth

Surface Area

150

Hydraulic Height

21

Drainage Area

2

Nid Storage

1123

Structural Height

21

Outlet Gates

None, Uncontrolled

Hazard Potential

Significant

Foundations

Soil

Nid Height

27
       
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.