Lower West Deer Lake Reservoir Report

Last Updated: December 6, 2025

Lower West Deer Lake, located in West Deer Township, Allegheny, Pennsylvania, is a picturesque recreational dam situated along the TR Little Deer Creek.


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Summary

Owned and regulated by the Pennsylvania Department of Environmental Protection, this earth dam stands at a height of 16 feet and spans a length of 285 feet, with a storage capacity of 37 acre-feet. The dam, primarily used for recreation, covers a surface area of 2.36 acres and has a drainage area of 0.6 square miles.

Despite its satisfactory condition assessment, Lower West Deer Lake poses a high hazard potential, emphasizing the importance of regular inspections and maintenance. The last inspection was conducted in October 2020, with an inspection frequency of once a year. With a spillway width of 159 feet and no associated locks, the dam serves as a vital recreational resource while also necessitating stringent risk management measures to ensure public safety.

In the realm of water resource and climate enthusiasts, Lower West Deer Lake presents a fascinating study in balancing recreational benefits with the potential risks associated with high-hazard dams. As a regulated and state-jurisdictional structure, this dam serves as a focal point for environmental stewardship and water management practices in the region, reflecting the delicate interplay between human enjoyment of natural resources and the imperative of safeguarding against potential hazards.

Dam Length

285

Dam Height

16

River Or Stream

TR LITTLE DEER CREEK

Primary Dam Type

Earth

Surface Area

2.36

Drainage Area

0.6

Nid Storage

37

Hazard Potential

High

Foundations

Unlisted/Unknown

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.