Lake Boyce Dam Reservoir Report

Last Updated: December 21, 2025

Lake Boyce Dam, located in Thomkins Cove, Rockland, New York, was completed in 1929 for the primary purpose of recreation.


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Summary

This private dam, standing at a height of 16 feet and stretching 275 feet in length, holds a maximum storage capacity of 85 acre-feet with normal storage at 69 acre-feet. However, recent data indicates a poor condition assessment and significant hazard potential, raising concerns for the dam's structural integrity and safety.

Managed by the NYS DEC, the dam overlooks the TR-Hudson River and is regulated, permitted, inspected, and enforced by state authorities. Despite its recreational significance, the dam's risk assessment is moderate, emphasizing the need for improved risk management measures to mitigate potential hazards. With a spillway width of 30 feet and uncontrolled spillway type, Lake Boyce Dam's last inspection in 2017 revealed a concerning condition, underscoring the importance of ongoing maintenance and safety protocols to ensure public and environmental safety around this water resource.

Water resource and climate enthusiasts visiting Lake Boyce Dam can appreciate its historical significance and natural beauty while recognizing the importance of ongoing monitoring and maintenance efforts to safeguard against potential risks and ensure the sustainable enjoyment of this recreational site along the Hudson River.

Year Completed

1929

Dam Length

275

Dam Height

16

River Or Stream

TR-HUDSON RIVER

Primary Dam Type

Earth

Surface Area

16

Drainage Area

0.47

Nid Storage

85

Hazard Potential

Significant

Nid Height

16
       
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.