Gage - South Dam Reservoir Report

Last Updated: December 15, 2025

Gage - South Dam, located in Passumpsic, Vermont, is a concrete gravity dam built in 1921 for hydroelectric purposes on the Passumpsic River.


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Summary

Standing at 18 feet high and 69 feet long, this dam has a storage capacity of 69 acre-feet and serves a drainage area of 413 square miles. With a maximum discharge capacity of 5440 cubic feet per second and an uncontrolled spillway width of 43 feet, the dam poses a low hazard potential and has a moderate risk assessment rating.

Owned by a public utility, Gage - South Dam falls under the jurisdiction of the Vermont Public Service Board and is regulated by the Federal Energy Regulatory Commission. The dam has one associated structure and is inspected every three years, with its last inspection conducted in June 2017. While the condition assessment is not available, the dam's emergency action plan was last revised in February 2014, showcasing a commitment to safety and risk management measures.

Overall, Gage - South Dam is a vital infrastructure supporting the region's energy needs while maintaining a balance between water resource management and environmental protection. With its historical significance and engineering design, this dam serves as a crucial asset in harnessing hydropower potential in Vermont's Caledonia County, contributing to sustainable development and climate resilience efforts in the area.

Year Completed

1921

Dam Length

69

Dam Height

18

River Or Stream

Passumpsic River

Primary Dam Type

Concrete

Surface Area

15

Drainage Area

413

Nid Storage

69

Hazard Potential

Low

Foundations

Rock

Nid Height

18
       
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.