Cyril Johnson Mill Dam Reservoir Report

Last Updated: December 6, 2025

Cyril Johnson Mill Dam, also known as Mill Pond or Furnace Pond, is a private-owned structure located in Stafford, Connecticut.


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Summary

This masonry dam on Furnace Brook has a height of 15 feet and a length of 232 feet, serving primarily for water supply purposes. With a surface area of 3 acres and a drainage area of 16.2 square miles, the dam plays a significant role in managing water resources in the region.

Despite being in a non-rated condition, Cyril Johnson Mill Dam has a hazard potential classified as significant. The dam's inspection frequency is set at every 5 years, although the last inspection date is unspecified. The presence of a spillway with a width of 102 feet indicates a measure for controlling water discharge. In the event of an emergency, the dam's emergency action plan (EAP) status, readiness, and compliance with guidelines remain unreported, posing potential risks to the surrounding community.

Located within the New England District, Cyril Johnson Mill Dam stands as a focal point for water resource management in Stafford. As a crucial component of the local water supply infrastructure, the dam's condition and regulatory oversight are essential factors to ensure the safety and sustainability of water resources in the area. The dam's historical background and construction details, however, remain undisclosed, leaving room for further exploration and assessment in the context of climate change and water management practices.

Dam Length

232

Dam Height

15

River Or Stream

FURNACE BROOK

Primary Dam Type

Masonry

Surface Area

3

Drainage Area

16.2

Hazard Potential

Significant

Nid Height

15
       
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.