Lost Lake Dam & Dike Reservoir Report

Last Updated: December 5, 2025

Lost Lake Dam & Dike, located in Brewster, New York, is a privately-owned structure that serves the primary purpose of recreation.


°F

°F

mph

Wind

%

Humidity

Summary

Completed in 1977, this earthen dam stands at a height of 10 feet and has a length of 900 feet, with a storage capacity of 362 acre-feet. Situated on the TR-E Branch Croton River, the dam has a spillway width of 9 feet and a maximum discharge of 259 cubic feet per second.

While the dam has a low hazard potential and is currently rated as "Not Rated" in terms of condition assessment, it is regulated by the New York State Department of Environmental Conservation (NYS DEC). The dam underwent its last inspection in November 2020, with inspections conducted every 4 years. Despite its moderate risk level, the dam does not currently have an Emergency Action Plan in place, highlighting the need for further risk management measures to ensure the safety and integrity of the structure. For water resource and climate enthusiasts, Lost Lake Dam & Dike presents an intriguing case study in the management of recreational dams within the state of New York.

Year Completed

1977

Dam Length

900

Dam Height

10

River Or Stream

TR-E BRANCH CROTON RIVER

Primary Dam Type

Earth

Surface Area

34

Drainage Area

2.95

Nid Storage

362

Hazard Potential

Low

Nid Height

10
       
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.