Greenbrier State Park Dam & Dike Reservoir Report

Last Updated: December 5, 2025

Greenbrier State Park Dam & Dike, located in Mount Lena/Greenbriar, Maryland, is a state-owned structure designed for flood risk reduction along the Little Beaver Creek-TR.


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Summary

Built in 1965, this earth dam stands at a height of 64 feet and stretches 445 feet in length, with a maximum storage capacity of 734 acre-feet. The dam's spillway, of uncontrolled type, boasts a width of 145 feet to handle a maximum discharge of 14,168 cubic feet per second.

Despite its critical role in flood control, the dam's condition assessment in April 2021 deemed it unsatisfactory, with a high hazard potential. The structure was last inspected in August 2021, with a recommended inspection frequency of once a year. The dam underwent structural modifications in 1996, and its emergency action plan (EAP) status is currently unknown. With a moderate risk assessment rating, the Greenbrier State Park Dam & Dike presents a complex management challenge that requires ongoing monitoring and maintenance to ensure public safety and infrastructure resilience in the face of changing climate patterns.

Years Modified

1996 - Structural

Year Completed

1965

Dam Length

445

Dam Height

64

River Or Stream

Little Beaver Creek-TR

Primary Dam Type

Earth

Surface Area

27

Drainage Area

0.8

Nid Storage

734

Outlet Gates

Valve - 0

Hazard Potential

High

Foundations

Rock

Nid Height

64
       
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.