Tarrywile Lake Dam Reservoir Report

Last Updated: December 5, 2025

Tarrywile Lake Dam, nestled in the picturesque city of Danbury, Connecticut, is a vital water resource managed by the local government for recreational purposes.


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Summary

Built in 1900, this earth dam stands at a height of 12 feet and spans a length of 180 feet, providing a storage capacity of 100 acre-feet and covering a surface area of 13.7 acres. With a drainage area of 320 square miles and a maximum discharge of 235 cubic feet per second, the dam plays a crucial role in regulating the flow of Parks Pond Brook.

Despite its age, Tarrywile Lake Dam has been assessed as being in satisfactory condition, with a significant hazard potential. Regular inspections take place every five years to ensure its structural integrity and safety. The dam's emergency action plan is kept up to date, although specific details regarding emergency preparedness measures are not provided in the data. Overall, Tarrywile Lake Dam serves as a valuable asset for both water resource management and recreational activities in the surrounding area.

In the event of an emergency, residents and visitors can rest assured that Tarrywile Lake Dam is monitored and regulated by the Connecticut Department of Energy and Environmental Protection (DEEP). With a designated state agency overseeing its permitting, inspection, and enforcement processes, the dam is subject to rigorous state regulations to mitigate risks and ensure public safety. As climate change continues to impact water resources and infrastructure, the maintenance and upkeep of dams like Tarrywile Lake Dam are essential in safeguarding communities and ecosystems against potential hazards.

Year Completed

1900

Dam Length

180

Dam Height

12

River Or Stream

PARKS POND BROOK

Primary Dam Type

Earth

Surface Area

13.7

Drainage Area

320

Nid Storage

100

Hazard Potential

Significant

Nid Height

12
       
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.