Shadow Lake Dam Reservoir Report

Last Updated: December 5, 2025

Shadow Lake Dam, also known as Mallorys Pond, is a local government-owned structure located in Ridgefield, Connecticut.


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Summary

Built in 1937, this earth dam stands at a height of 25 feet and spans 410 feet in length, providing recreational opportunities in the area. The dam has a storage capacity of 80 acre-feet, with a normal storage level of 69 acre-feet, covering a surface area of 7 acres and draining a watershed area of 0.43 square miles.

Managed by the Connecticut Department of Energy and Environmental Protection (DEEP), Shadow Lake Dam is regulated by the state and undergoes regular inspections to ensure its safety. The dam has an uncontrolled spillway type with a width of 30 feet and a significant hazard potential, although its condition assessment is fair as of the last inspection in April 2020. With a moderate risk rating, the dam is equipped with emergency action plans to mitigate any potential risks and meet safety guidelines.

Located along a tributary to Miry Brook, Shadow Lake Dam serves as a vital structure for water resource management and flood control in the region. Its presence not only offers recreational benefits to the community but also highlights the importance of maintaining and monitoring dam infrastructure to ensure public safety and environmental sustainability in the face of changing climate conditions.

Year Completed

1937

Dam Length

410

Dam Height

25

River Or Stream

TRIB TO MIRY BROOK

Primary Dam Type

Earth

Surface Area

7

Drainage Area

0.43

Nid Storage

80

Outlet Gates

None

Hazard Potential

Significant

Nid Height

25
       
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.