Muddy Run Main Dam Reservoir Report

Last Updated: December 8, 2025

Muddy Run Main Dam, located in Lancaster, Pennsylvania, is a pivotal structure along the Susquehanna River, designed by the Philadelphia Electric Company and completed in 1967.


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Summary

This rockfill dam stands at an impressive height of 260 feet with a length of 4800 feet, serving primarily for hydroelectric purposes. With a storage capacity of 60,500 acre-feet and a maximum discharge of 20,000 cubic feet per second, the dam plays a crucial role in managing water resources and generating clean energy for the region.

Despite its high hazard potential, the dam's condition assessment is not available, highlighting the need for regular inspections and risk management measures. The Federal Energy Regulatory Commission oversees the regulatory aspects of the dam, ensuring its safety and compliance with standards. With a moderate risk classification, the dam's Emergency Action Plan is being regularly updated to meet guidelines and prepare for any potential emergencies that may arise. Overall, Muddy Run Main Dam stands as a vital infrastructure contributing to water resource management and climate-friendly energy production in the region.

Year Completed

1967

Dam Length

4800

Dam Height

260

River Or Stream

Susquehanna River

Primary Dam Type

Rockfill

Surface Area

1000

Drainage Area

9.2

Nid Storage

60500

Hazard Potential

High

Nid Height

260
       
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.