Fawn Mine #91 Refuse Impoundment Reservoir Report

Last Updated: December 6, 2025

Fawn Mine #91 Refuse Impoundment is a privately-owned structure located in Clinton Township, Butler County, Pennsylvania.


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Summary

This earth dam, with a height of 120 feet and a length of 1250 feet, serves as a critical water resource for the area, providing a storage capacity of 985 acre-feet. The impoundment covers a surface area of 24.2 acres and has a drainage area of 0.13 square miles, with a hazard potential classified as high.

Regulated by the Pennsylvania Department of Environmental Protection, the dam is subject to regular inspections to ensure its structural integrity and safety. The most recent inspection in October 2018 reported the impoundment's condition as fair. While the dam is currently in compliance with state regulations, it is essential to continue monitoring and implementing risk management measures to mitigate potential hazards and ensure the long-term sustainability of this vital water resource in the region. As climate change impacts water resources, structures like Fawn Mine #91 Refuse Impoundment play a crucial role in water storage and management, highlighting the importance of proactive maintenance and monitoring to adapt to changing environmental conditions.

Dam Length

1250

Dam Height

120

River Or Stream

TR LARDINTOWN RUN

Primary Dam Type

Earth

Surface Area

24.2

Drainage Area

0.13

Nid Storage

985

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

120
       
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.