Arnold Falls Reservoir Report

Last Updated: December 15, 2025

Arnold Falls, also known as Tsg&E No.


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Summary

1 1/2, is a hydroelectric dam located in St. Johnsbury, Vermont, along the Passumpsic River. This timber crib dam stands at a height of 21 feet and has a length of 285 feet, with a storage capacity of 170 acre-feet. The dam serves a primary purpose of generating hydroelectric power and is owned by a public utility in Vermont.

Despite being a low hazard potential structure with a "Not Rated" condition assessment, Arnold Falls has not been inspected since May 2000. The dam, which is under state jurisdiction, does not currently have state permitting or inspection requirements. However, with a drainage area of 245 square miles and a surface area of 7 acres, it plays a crucial role in managing water resources in Caledonia County and Vermont.

For water resource and climate enthusiasts, Arnold Falls represents a unique opportunity to explore the intersection of renewable energy generation and dam infrastructure in rural New England. With its location in a picturesque setting along the Passumpsic River and its historical significance in harnessing hydropower, Arnold Falls offers a fascinating case study in sustainable water management practices and the challenges of maintaining aging infrastructure in the face of changing climate conditions.

Dam Length

285

Dam Height

21

River Or Stream

PASSUMPSIC RIVER

Primary Dam Type

Timber Crib

Surface Area

7

Hydraulic Height

21

Drainage Area

245

Nid Storage

170

Structural Height

21

Hazard Potential

Low

Foundations

Rock, Soil

Nid Height

21
       
Seasonal Comparison

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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.