Mahoning Creek Dam Reservoir Report

Last Updated: December 6, 2025

Mahoning Creek Dam, also known as Mahoning Creek Lake, is a gravity type dam located in Putneyville, Pennsylvania.


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Summary

Built in 1941 by the US Army Corps of Engineers, the dam serves a primary purpose of flood risk reduction while also providing benefits for fish and wildlife, recreation, and water storage. With a structural height of 162 feet and a length of 926 feet, the dam has a storage capacity of 94,000 acre-feet and covers a surface area of 280 acres.

The dam's spillway width of 150 feet and controlled spillway type help manage water levels during high flow events, with a maximum discharge capacity of 103,000 cubic feet per second. Despite its high hazard potential, the dam is regularly inspected and monitored to ensure its structural integrity and reduce flood risks. The US Army Corps of Engineers implements risk management measures, including emergency action plans, regular maintenance, and public outreach, to address potential dam-related emergencies and enhance community preparedness.

As a critical infrastructure for flood mitigation in the region, Mahoning Creek Dam plays a vital role in protecting surrounding communities from potential flooding events. The dam's risk management strategies and ongoing maintenance efforts demonstrate a commitment to ensuring the safety and resilience of the dam and the surrounding area in the face of changing climate patterns and extreme weather events.

Year Completed

1941

Dam Length

926

River Or Stream

MAHONING CREEK

Primary Dam Type

Gravity

Surface Area

280

Hydraulic Height

162

Drainage Area

340

Nid Storage

94000

Structural Height

162

Outlet Gates

Slide (sluice gate) - 6, Valve - 4, Vertical Lift - 5

Hazard Potential

High

Foundations

Rock

Nid Height

162
       
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.