Lake Helene Dam Reservoir Report

Last Updated: December 5, 2025

Lake Helene Dam, also known as Kentlands - Lake Helene, is a local government-owned structure located in Gaithersburg, Maryland.


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Summary

Built in 1950 by Woodward Clyde Consultants, this earth dam stands at a height of 27 feet and spans 420 feet in length. Its primary purpose is flood risk reduction, with a normal storage capacity of 1 acre-foot and a maximum storage of 177 acre-feet.

The dam is state-regulated by the Maryland Dam Safety agency, with regular inspections and enforcement measures in place to ensure its structural integrity. Despite being classified as having a high hazard potential, the dam's condition assessment remains satisfactory as of its last inspection in April 2021. It is designated as a high-risk structure, warranting close monitoring and risk management measures to mitigate potential hazards.

Visitors to Lake Helene Dam can appreciate its significance in safeguarding the surrounding area from flood risks associated with the Muddy Branch-TR river. The dam's historical and engineering importance, combined with its critical role in water resource management, make it a notable site for water resource and climate enthusiasts to explore and learn about the intersection of infrastructure and environmental conservation.

Years Modified

1990 - Hydraulic, 1990 - Structural

Year Completed

1950

Dam Length

420

Dam Height

27

River Or Stream

Muddy Branch-TR

Primary Dam Type

Earth

Surface Area

1

Drainage Area

0.22

Nid Storage

177

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

27
       
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.