Mirror Lake Reservoir Report

Last Updated: December 15, 2025

Mirror Lake, also known as Number 10 Pond, is a picturesque water resource located in Calais, Vermont.


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Summary

This private lake serves as a popular recreational spot, offering opportunities for fishing, boating, and other water activities. Built in 1820, the dam at Mirror Lake stands at 8 feet tall and spans 125 feet in length, providing a storage capacity of 540 acre-feet.

Despite its historical significance and recreational value, Mirror Lake is facing challenges in terms of its condition and hazard potential. The dam has been assessed as poor, with a significant hazard potential, highlighting the need for regular inspections and maintenance. The last inspection in 2015 revealed the dam's deteriorating condition, prompting the need for risk management measures to ensure the safety of the surrounding area.

For water resource and climate enthusiasts, Mirror Lake presents an intriguing case study of balancing recreational use with dam safety and maintenance. As a vital part of the local ecosystem and community, efforts to preserve and protect Mirror Lake are essential to ensure its continued enjoyment for future generations. With its stunning natural beauty and historical significance, Mirror Lake serves as a reminder of the importance of sustainable water resource management in the face of changing environmental conditions.

Year Completed

1820

Dam Length

125

Dam Height

8

River Or Stream

DUGAR BROOK-TR

Primary Dam Type

Masonry

Surface Area

86

Hydraulic Height

8

Drainage Area

5.47

Nid Storage

540

Structural Height

8

Hazard Potential

Significant

Foundations

Rock, Soil

Nid Height

8
       
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.