High Dam Reservoir Report

Last Updated: December 6, 2025

High Dam, also known as Lock No.6 Dam, is a gravity dam located in Oswego, New York, along the Oswego River.


°F

°F

mph

Wind

%

Humidity

Summary

Built in 1928, this state-owned structure serves primarily as a hydroelectric facility, with a secondary purpose of navigation. Standing at 35 feet tall and stretching 900 feet in length, the dam has a storage capacity of 3,927 acre-feet and can discharge a maximum of 32,500 cubic feet per second.

Managed by the Federal Energy Regulatory Commission, High Dam poses a high hazard potential due to its location and design. Despite its age, the dam has been inspected regularly, with the last inspection conducted in September 2020. An emergency action plan has been prepared and revised, ensuring that the surrounding area is prepared for any potential risks associated with the dam.

With a moderate risk assessment rating, High Dam remains a key feature in the water resource management of the area. Its historical significance and continued function as a hydroelectric facility make it a valuable asset for both energy production and waterway navigation in the region.

Year Completed

1928

Dam Length

900

Dam Height

35

River Or Stream

Oswego River

Primary Dam Type

Gravity

Surface Area

240

Drainage Area

5097

Nid Storage

3927

Outlet Gates

Slide (sluice gate) - 1

Hazard Potential

High

Foundations

Rock

Nid Height

35
       
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.