Holly Hills Section 4 Swm Pond 1 Reservoir Report

Last Updated: December 5, 2025

Holly Hills Section 4 Swm Pond 1, located in Frederick, Maryland, serves as a vital structure for flood risk reduction along the Long Branch river.


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Summary

Built in 2001 by designers Clark Finefrock & Sackett, this private pond stands at a height of 26 feet with a length of 500 feet, providing a storage capacity of 73 acre-feet. Despite its uncontrolled spillway type, the dam is in satisfactory condition according to the latest assessment in April 2021.

With a hazard potential deemed as significant, Holly Hills Section 4 Swm Pond 1 undergoes inspections every three years to ensure its structural integrity. The dam's emergency action plan was last revised in February 2022, reflecting a proactive approach to risk management. While the risk assessment categorizes the pond as moderate, with a score of 3, the structure continues to play a crucial role in protecting the surrounding area from potential flooding events. As water resource and climate enthusiasts, understanding the importance of infrastructure like Holly Hills Section 4 Swm Pond 1 highlights the ongoing efforts to safeguard communities against natural disasters.

Year Completed

2001

Dam Length

500

Dam Height

26

River Or Stream

Long Branch

Primary Dam Type

Earth

Drainage Area

0.9

Nid Storage

73

Outlet Gates

Needle - 0

Hazard Potential

Significant

Foundations

Rock, Soil

Nid Height

26
       
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.