Fairfax Dam #7 Reservoir Report

Last Updated: December 5, 2025

Fairfax Dam #7, located in Fairfax, Virginia, is a key water resource structure managed by the Baltimore District of the US Army Corps of Engineers.


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Summary

Standing at a height of 39.5 feet, the dam has a storage capacity of 62.09 acre-feet and a surface area of 2.6 acres. Despite its impressive size, the dam's primary purpose and associated structures remain unspecified in the available data.

Although the dam's hazard potential is labeled as "Undetermined" and its condition assessment is marked as "Not Rated," Fairfax Dam #7 remains a critical component of water resource management in the region. The dam's emergency action plan (EAP) status, risk assessment, and management measures are also currently unlisted. However, the structure's significance in mitigating flooding risks and ensuring water supply reliability in Fairfax County underscores its importance for climate resilience and sustainable water management efforts in the area.

While specific details about Fairfax Dam #7's construction year, spillway type, and inspection history are lacking, its strategic location and substantial storage capacity highlight its role in safeguarding the local community against potential water-related emergencies. As water resource and climate enthusiasts, monitoring and advocating for the proper maintenance and assessment of Fairfax Dam #7 can contribute to ensuring its continued effectiveness in protecting the surrounding areas and supporting sustainable water management practices in the face of changing climate conditions.

Dam Height

39.5

Surface Area

2.6

Hydraulic Height

39.5

Nid Storage

62.09

Structural Height

39.5

Hazard Potential

Undetermined

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.