Island Creek Dam Reservoir Report

Last Updated: December 5, 2025

Island Creek Dam, located in Fairfax, Virginia, is a private dam managed by the Department of Conservation and Recreation.


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Summary

The dam is situated on the Long Branch tributary and serves the primary purpose of flood risk reduction. With a structural height of 39.5 feet and a length of 720 feet, the dam has a NID storage capacity of 70.07 acre-feet and a normal storage capacity of 22.28 acre-feet. The dam has a significant hazard potential and is currently rated as "Not Rated" in terms of condition assessment.

Despite lacking certain detailed information such as the year of completion and specific construction features, Island Creek Dam remains a vital structure for flood risk reduction in the area. The dam also serves additional purposes such as creating a fish and wildlife pond. With its strategic location and critical role in managing local water resources, Island Creek Dam is an essential part of the water infrastructure in Fairfax, Virginia. Water resource and climate enthusiasts will appreciate the significance of this dam in mitigating flood risks and supporting environmental conservation efforts in the region.

Dam Length

720

Dam Height

39.5

River Or Stream

Long Branch tributary

Primary Dam Type

Earth

Surface Area

2.15

Hydraulic Height

39.5

Nid Storage

70.07

Structural Height

39.5

Hazard Potential

Significant

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.