Little Falls Dam - Potomac River Reservoir Report

Last Updated: December 5, 2025

Little Falls Dam on the Potomac River, also known as Potomac River Dam #1, is a gravity dam managed by the US Army Corps of Engineers in Montgomery County, Maryland.


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Summary

Completed in 1958, this dam primarily serves as a water supply source, with a normal storage capacity of 1008 acre-feet and a total storage capacity of 13360 acre-feet. The dam stands at a height of 12 feet and spans a length of 1300 feet, making it a vital infrastructure for regulating water flow and ensuring water availability in the region.

The dam has a low hazard potential and is not currently rated for its condition. However, it is subject to regular inspections by the Maryland Dam Safety agency, with the last inspection conducted in December 2013. Little Falls Dam plays a crucial role in managing water resources in the area, with a maximum discharge capacity of 484,000 cubic feet per second. Despite its age, the dam has undergone modifications in 1986 to enhance its hydraulic capabilities, reflecting a commitment to maintaining and improving its functionality for the future.

Located in Washington, DC, the Little Falls Dam is part of the larger water management infrastructure on the Potomac River. With its rock foundation and uncontrolled spillway, it ensures the efficient control of water flow and protects against potential flooding events. As climate change brings about increased variability in weather patterns, the significance of dams like Little Falls in ensuring water security and mitigating risks from extreme weather events becomes ever more critical.

Years Modified

1986 - Hydraulic

Year Completed

1958

Dam Length

1300

Dam Height

12

River Or Stream

Potomac River

Primary Dam Type

Gravity

Surface Area

167.9

Drainage Area

11430

Nid Storage

13360

Outlet Gates

Needle - 0

Hazard Potential

Low

Foundations

Rock

Nid Height

12
       
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.