Allegheny River Lock And Dam 5 Reservoir Report

Last Updated: December 6, 2025

Allegheny River Lock and Dam 5, located in Freeport, Pennsylvania, is a gravity dam completed in 1927 by the US Army Corps of Engineers for navigation purposes on the Allegheny River.


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Summary

With a structural height of 16 feet and a length of 856 feet, the dam has a maximum storage capacity of 9,800 acre-feet and serves a drainage area of 9,351 square miles. The dam features a multi-arch core type built on a rock foundation, with an uncontrolled spillway width of 632 feet to manage maximum discharge of 82,000 cubic feet per second.

The dam, with a low hazard potential and a moderate risk rating, is continuously monitored by the US Army Corps of Engineers to address flood risks, manage water levels, and ensure structural integrity. Emergency action plans and inundation maps are prepared and regularly updated, with coordinated efforts with local emergency managers to raise public awareness and readiness in case of a dam-related emergency. Regular maintenance and repairs are carried out to keep the dam functioning effectively, with a focus on prioritizing activities to mitigate risks and engage stakeholders in risk management measures.

As a vital component of the Allegheny River's water resource management system, Allegheny River Lock and Dam 5 plays a crucial role in regulating water flow, supporting navigation, and reducing flood risks in the region. The ongoing efforts by the US Army Corps of Engineers ensure the dam's resilience and readiness to address challenges posed by severe weather events and changing hydrological conditions, highlighting the importance of proactive risk management and community engagement in safeguarding water resources and climate resilience.

Year Completed

1927

Dam Length

856

River Or Stream

Allegheny River

Primary Dam Type

Gravity

Surface Area

660

Length Of Locks

360

Hydraulic Height

16

Drainage Area

9351

Nid Storage

95

Structural Height

16

Hazard Potential

Low

Foundations

Rock

Nid Height

16
       
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.