Treman Lake Dam Reservoir Report

Last Updated: December 7, 2025

Treman Lake Dam, located in Ithaca, New York, is a state-owned structure with a primary purpose of recreation.


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Summary

Completed in 1930, this arch-type dam stands at a height of 36 feet and spans 85 feet in length, creating a storage capacity of 300 acre-feet for Treman Lake. The dam is situated on Buttermilk Creek and is regulated by the New York State Department of Environmental Conservation.

Despite its recreational importance, Treman Lake Dam poses a significant hazard potential due to its poor condition assessment. The dam has a very high risk rating and is in need of immediate attention to ensure public safety and prevent potential environmental damage. The last inspection in November 2018 highlighted the urgent need for maintenance and risk management measures to be implemented.

Water resource and climate enthusiasts should take note of Treman Lake Dam's critical state and advocate for proper maintenance and rehabilitation efforts to mitigate the risk of dam failure. As a key infrastructure for recreation and water storage in the region, ensuring the safety and longevity of Treman Lake Dam is crucial for preserving the natural environment and safeguarding the surrounding community.

Year Completed

1930

Dam Length

85

Dam Height

36

River Or Stream

BUTTERMILK CREEK

Primary Dam Type

Arch

Surface Area

25

Drainage Area

11

Nid Storage

300

Hazard Potential

Significant

Nid Height

36
       
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.