Kalnasy Dam Reservoir Report

Last Updated: December 28, 2025

Kalnasy Dam, located in Loudoun, Virginia, is a vital water resource structure that serves multiple purposes, including irrigation and recreation.


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Summary

Managed by the Department of Conservation and Recreation, this earth dam stands at a height of 26.1 feet and stretches 360 feet in length, providing a storage capacity of 116.1 acre-feet. Situated on the South Fork Catoctin Creek tributary, the dam's primary function is for recreational use, offering a surface area of 7.36 acres for visitors to enjoy.

Despite its fair condition assessment and high hazard potential, Kalnasy Dam is regularly inspected to ensure its structural integrity and the safety of those in its vicinity. The last inspection in February 2018 revealed no immediate concerns, with a defined emergency action plan in place. With state regulatory agencies overseeing its operation, permitting, and enforcement, the dam continues to play a crucial role in water management within the region. As climate change impacts water resources, dams like Kalnasy are essential for maintaining water supply and mitigating risks associated with extreme weather events.

Dam Length

360

Dam Height

26.1

River Or Stream

South Fork Catoctin Creek tributary

Surface Area

7.36

Hydraulic Height

26.1

Drainage Area

1.76

Nid Storage

116.1

Structural Height

26.1

Hazard Potential

High

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.