Allegheny River Lock And Dam 4 Reservoir Report

Last Updated: December 6, 2025

Allegheny River Lock and Dam 4, also known as Allegheny River Pool 04, is a federal-owned structure located in Brackenridge, Pennsylvania.


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Summary

Built by the US Army Corps of Engineers in 1927, this gravity dam serves primarily for navigation purposes on the Allegheny River. With a structural height of 29 feet and a length of 954 feet, the dam creates a reservoir with a storage capacity of 9,000 acre-feet and a surface area of 710 acres.

Despite being classified with a moderate risk assessment, the dam has operated without incident for over 80 years. Risk management measures are in place to ensure public safety and economic benefits, including routine monitoring, emergency action planning, and communication with external partners. In the event of a potential breach or flooding scenario, emergency exercises and comprehensive inspections are conducted to mitigate risks and protect residents and infrastructure in the area.

The US Army Corps of Engineers maintains a proactive approach to risk management, conducting regular assessments and surveillance to monitor the dam's condition and potential threats. By staying vigilant and prepared for emergencies, the agency aims to safeguard the integrity of the dam, prevent downstream flooding, and ensure the continued navigation and economic benefits provided by Allegheny River Lock and Dam 4.

Year Completed

1927

Dam Length

954

River Or Stream

ALLEGHENY RIVER

Primary Dam Type

Gravity

Surface Area

710

Length Of Locks

360

Hydraulic Height

29

Drainage Area

11419

Nid Storage

9000

Structural Height

29

Outlet Gates

None - 0, Uncontrolled - 0

Hazard Potential

Significant

Foundations

Rock

Nid Height

29
       
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.