Lenape Lake Dam Reservoir Report

Last Updated: December 6, 2025

Lenape Lake Dam, located in Morsston, Sullivan County, New York, was completed in 1920 and serves primarily for flood risk reduction.


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Summary

This private dam, standing at a height of 20 feet and stretching 75 feet in length, has a storage capacity of 260 acre-feet and a maximum discharge of 95 cubic feet per second. With a low hazard potential but a very high risk assessment rating, Lenape Lake Dam is regulated by the New York State Department of Environmental Conservation and undergoes regular inspections to ensure its safety and integrity.

Despite its primary purpose of flood risk reduction, Lenape Lake Dam also caters to recreational activities, making it a popular spot for water resource and climate enthusiasts. The dam encompasses Lenape Lake, offering a surface area of 26 acres for visitors to enjoy. While the dam itself has not been rated for its condition, its emergency action plan status and risk management measures are not currently available. Overall, Lenape Lake Dam presents a fascinating blend of functionality, recreational opportunities, and potential risks that are of interest to those passionate about water resources and climate sustainability.

Year Completed

1920

Dam Length

75

Dam Height

20

River Or Stream

TR-MATAWA LAKE

Primary Dam Type

Earth

Surface Area

26

Nid Storage

260

Hazard Potential

Low

Nid Height

20
       
Seasonal Comparison

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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.