Lake John Reservoir Report

Last Updated: December 9, 2025

Lake John, located in Sullivan County, Pennsylvania, is a state-owned reservoir regulated by the Pennsylvania Department of Environmental Protection.



Weather Forecast

Next 5 Days

°F

°F

mph

Wind

%

Humidity

Summary

Built in 1958, this Earth-type dam stands at 15 feet high and spans 325 feet in length, providing a recreational haven with a storage capacity of 509 acre-feet. The dam, situated on the TR MEHOOPANY CREEK, serves as a low hazard structure with a surface area of 75 acres and a drainage area of 1.2 square miles.

Despite its modest size, Lake John offers a serene escape for water resource and climate enthusiasts seeking outdoor adventure in the picturesque surroundings of Colley Township. The dam's primary purpose is for recreation, attracting visitors with its tranquil waters and abundant wildlife. The last inspection in May 2016 deemed the dam to be in good condition, with a low hazard potential and an inspection frequency of every five years.

With its rich history and scenic beauty, Lake John continues to be a beloved destination for locals and tourists alike, offering a peaceful retreat for fishing, boating, and nature appreciation. As a vital resource for the community, this state-regulated reservoir not only provides recreational opportunities but also serves as a reminder of the importance of sustainable water management practices in safeguarding our natural environment for future generations.

Year Completed

1958

Dam Length

325

Dam Height

15

River Or Stream

TR MEHOOPANY CREEK

Primary Dam Type

Earth

Surface Area

75

Drainage Area

1.2

Nid Storage

509

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

15
       
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.