Port Leyden Reservoir Report

Last Updated: December 10, 2025

Port Leyden, also known as Port Leyden Lower Dam, is a privately owned hydroelectric facility located in Lewis, New York, along the Black River.


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Summary

Constructed in 1983 by International Engineering Co., this concrete dam stands at 31.5 feet tall and has a storage capacity of 150 acre-feet, serving the primary purpose of hydroelectric power generation. It is regulated by the New York State Department of Environmental Conservation and falls under the jurisdiction of the Federal Energy Regulatory Commission.

With a low hazard potential and moderate risk assessment rating, Port Leyden plays a crucial role in providing renewable energy while managing water resources effectively. The dam has a spillway width of 160 feet and a maximum discharge capacity of 18,500 cubic feet per second, contributing to the overall water management system in the region. Regular inspections and enforcement by state and federal agencies ensure the safety and reliability of this essential infrastructure for water resource and climate enthusiasts in the area.

Year Completed

1983

Dam Length

310

Dam Height

31.5

River Or Stream

Black River

Primary Dam Type

Concrete

Surface Area

23

Drainage Area

429

Nid Storage

150

Hazard Potential

Low

Foundations

Rock

Nid Height

32
       
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.