Lower Tumbling Run Reservoir Report

Last Updated: December 7, 2025

Lower Tumbling Run, also known as Silver Creek Reservoir, is a vital water resource in North Manheim Township, Pennsylvania.


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Summary

Managed by the local government, this earth dam was completed in 1832 with a primary purpose of water supply. With a dam height of 49 feet and a storage capacity of 698 acre-feet, the reservoir serves the surrounding area with a normal storage of 531 acre-feet and covers a surface area of 26 acres.

Despite its historical significance and essential role in water supply, Lower Tumbling Run faces challenges in terms of its condition assessment, with a poor rating and high hazard potential. The dam's last inspection in April 2020 highlighted the need for attention and potential risk management measures. As a regulated structure under the Pennsylvania Department of Environmental Protection, ongoing inspection, enforcement, and permitting are in place to ensure the safety and integrity of this critical water resource.

As a key component of the Tumbling Run watershed and the broader water infrastructure in Schuylkill County, Lower Tumbling Run is a focal point for water resource and climate enthusiasts. Its role in supplying water to the community, coupled with the need for continued monitoring and maintenance, underscores the importance of sustainable water management practices in safeguarding our natural resources for future generations.

Year Completed

1832

Dam Length

430

Dam Height

49

River Or Stream

TUMBLING RUN

Primary Dam Type

Earth

Surface Area

26

Drainage Area

6

Nid Storage

698

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

49
       
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.