Gray's Landing Lock And Dam Reservoir Report

Last Updated: December 5, 2025

Gray's Landing Lock and Dam, located in Greene, Pennsylvania, along the Monongahela River, serves as a crucial structure for navigation purposes in the region.


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Summary

Constructed in 1995 by the US Army Corps of Engineers, this gravity dam stands at a height of 33 feet with a length of 680 feet, providing storage of up to 12,500 acre-feet of water. Equipped with a single lock measuring 720 feet in length, the dam also features an uncontrolled spillway with a width of 576 feet to manage maximum discharges of 80,000 cubic feet per second.

With a significant hazard potential, Gray's Landing Lock and Dam undergoes regular inspections and risk assessments to ensure its structural integrity and the safety of surrounding communities. The US Army Corps of Engineers follows a comprehensive risk management plan, involving continuous monitoring, maintenance, and collaboration with local emergency managers to address flood risks associated with the dam. By updating emergency action plans and engaging with the public, the Corps aims to enhance preparedness and response capabilities in the event of a dam-related emergency, emphasizing the importance of proactive measures and awareness in safeguarding the dam and its surroundings from potential risks.

Year Completed

1995

Dam Length

680

River Or Stream

MONONGAHELA RIVER

Primary Dam Type

Gravity

Surface Area

796

Length Of Locks

720

Hydraulic Height

33

Drainage Area

4460

Nid Storage

12500

Structural Height

33

Outlet Gates

None - 0, Uncontrolled - 0

Hazard Potential

Significant

Foundations

Rock

Nid Height

33
       
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.