Lower (Pa-487a) Reservoir Report

Last Updated: December 5, 2025

Lower (Pa-487a) is a state-owned earth dam located in Crawford County, Pennsylvania, specifically in East Fallowfield Township.


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Summary

Built in 1973, the dam stands at a height of 20 feet and spans 1700 feet in length, serving primarily for flood risk reduction along Crooked Creek. With a storage capacity of 7810 acre-feet, the dam plays a crucial role in managing water resources and protecting the surrounding area from potential flooding events.

Managed by the Pennsylvania Department of Environmental Protection, Lower (Pa-487a) is subject to state regulation, inspection, and enforcement to ensure its structural integrity and safety. Despite being classified as having a high hazard potential, the dam is currently in fair condition as of the last inspection in June 2020. While the dam does not have an Emergency Action Plan in place at this time, its maintenance and monitoring are carried out to meet state guidelines and ensure its effectiveness in flood risk reduction.

For water resource and climate enthusiasts, Lower (Pa-487a) represents a vital piece of infrastructure in Pennsylvania's efforts to manage flood risks and protect communities along Crooked Creek. With its strategic location and significant storage capacity, the dam serves as a key asset in safeguarding the area from potential inundation events. As climate change continues to impact weather patterns and increase the frequency of extreme events, the importance of well-maintained dams like Lower (Pa-487a) in mitigating flood risks and ensuring water resource sustainability cannot be overstated.

Year Completed

1973

Dam Length

1700

Dam Height

20

River Or Stream

CROOKED CREEK

Primary Dam Type

Earth

Surface Area

193

Drainage Area

20.1

Nid Storage

7810

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

20
       
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.