Lake Frank Reservoir Report

Last Updated: December 5, 2025

Lake Frank, also known as Upper Rock Creek Watershed Site 1, is a gravity dam located in Twin Brook Forest, Maryland.


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Summary

Managed by the local government, this recreational site was completed in 1967 and has a dam height of 78 feet, with a storage capacity of 7854 acre-feet. With a surface area of 56 acres and a drainage area of 12.2 square miles, the dam serves as a vital resource for the community.

The dam, designed by USDA NRCS, is regulated by the Maryland Dam Safety agency and undergoes regular inspections to ensure its safety and functionality. Despite being classified as having a high hazard potential, the dam is currently in fair condition and meets emergency action plan guidelines. With a spillway width of 150 feet and a maximum discharge capacity of 24317 cubic feet per second, Lake Frank plays a crucial role in managing water resources in the area.

Surrounded by the North Branch and TR-Rock Creek, Lake Frank is not only a recreational hub but also a key component in the region's water management infrastructure. As climate change continues to impact water resources, the maintenance and regulation of dams like Lake Frank are essential in ensuring the safety and sustainability of water sources for future generations.

Year Completed

1967

Dam Length

576

Dam Height

78

River Or Stream

North Branch;TR-Rock Creek

Primary Dam Type

Gravity

Surface Area

56

Drainage Area

12.2

Nid Storage

7854

Outlet Gates

Slide (sluice gate) - 0

Hazard Potential

High

Foundations

Rock

Nid Height

78
       
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.