Brighton Reservoir Report

Last Updated: December 5, 2025

Brighton, also known as Tridelphia Lake Dam, is a significant water resource structure located in Montgomery County, Maryland, near Laurel.


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Summary

Built in 1943, this buttress dam serves the dual purposes of hydroelectric power generation and water supply, with a maximum storage capacity of 19,560 acre-feet and a normal storage level of 17,200 acre-feet. The dam stands at a height of 82 feet and stretches 995 feet in length, with a spillway width of 340 feet to control water discharge.

Managed by the local government and regulated by the Maryland Dam Safety agency, Brighton is situated along the Patuxent River and falls under the jurisdiction of the Federal Energy Regulatory Commission. With a high hazard potential and very high risk assessment rating, the dam is subject to regular inspections and emergency action plan requirements to ensure public safety. The dam's outlet gates consist of Tainter (radial) structures, totaling 13 in number, to manage water flow and maintain operational efficiency.

Despite its age, Brighton continues to play a crucial role in water management and renewable energy production in the region. With a strong emphasis on safety and compliance with regulatory standards, the dam remains a vital component of Maryland's water infrastructure, highlighting the intersection of water resource management and climate resilience in a changing environment.

Year Completed

1943

Dam Length

995

Dam Height

82

River Or Stream

Patuxent River

Primary Dam Type

Buttress

Surface Area

800

Drainage Area

77

Nid Storage

19560

Outlet Gates

Tainter (radial) - 13

Hazard Potential

High

Foundations

Rock, Soil

Nid Height

82
       
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.