East Branch Dam Reservoir Report

Last Updated: December 15, 2025

East Branch Dam, also known as East Branch-Clarion River Lake, is a federal-owned structure located in Johnsonburg, Pennsylvania.


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Summary

Completed in 1952 by the US Army Corps of Engineers, this earth-type dam stands at a structural height of 184 feet and spans 1725 feet across the Clarion River. With a maximum storage capacity of 103,000 acre-feet and a surface area of 1160 acres, the dam primarily serves the purpose of flood risk reduction while also supporting fish and wildlife habitats, recreation, and other purposes.

Despite its high hazard potential, East Branch Dam is equipped with an uncontrolled spillway and eight slide gates for water release and management. The US Army Corps of Engineers actively manages the dam-related flood risks through regular inspections, maintenance, and engagement with local emergency managers and the public. The dam's emergency action plan, updated regularly, ensures preparedness and response readiness in case of a dam-related emergency. While the dam faces inherent risks during severe weather events, its risk management measures prioritize safety, risk reduction, and community awareness to safeguard against potential flooding incidents.

Year Completed

1952

Dam Length

1725

River Or Stream

CLARION RIVER

Primary Dam Type

Earth

Surface Area

1160

Hydraulic Height

173

Drainage Area

72

Nid Storage

103000

Structural Height

184

Outlet Gates

Slide (sluice gate) - 8

Hazard Potential

High

Foundations

Rock

Nid Height

184
       
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.
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