Sweet Arrow Lake Reservoir Report

Last Updated: December 6, 2025

Sweet Arrow Lake, located in Pine Grove Township, Pennsylvania, is a picturesque reservoir primarily designed for recreational purposes.


°F

°F

mph

Wind

%

Humidity

Summary

The dam, completed in 1923, stands at a height of 36 feet and spans 480 feet in length, holding a maximum storage capacity of 3,110 acre-feet. The lake covers a surface area of 92 acres and is fed by the Upper Little Swatara Creek, with a drainage area of 20.5 square miles.

Managed by the Pennsylvania Department of Environmental Protection, Sweet Arrow Lake is regulated and inspected to ensure its structural integrity and public safety. Despite being classified as having a high hazard potential, the dam is currently in satisfactory condition and undergoes regular inspections. The surrounding area offers opportunities for outdoor activities such as fishing, boating, and picnicking, making it a popular destination for water resource and climate enthusiasts alike.

With its rich history dating back nearly a century and its stunning natural setting, Sweet Arrow Lake continues to be a cherished spot for locals and visitors to enjoy the beauty of Pennsylvania's water resources while emphasizing the importance of proper dam management and safety protocols in the face of changing climate conditions.

Years Modified

2003 - Hydraulic, 2003 - Structural, 2006 - Other

Year Completed

1923

Dam Length

480

Dam Height

36

River Or Stream

UPPER LITTLE SWATARA CREEK

Primary Dam Type

Earth

Surface Area

92

Drainage Area

20.5

Nid Storage

3110

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

36
       
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.