Dieterich Dam #2 Reservoir Report

Last Updated: December 6, 2025

Dieterich Dam #2 is a historic masonry dam located in Millbrook, New York, along the Mill Brook river.


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Summary

Built in 1910, the dam serves multiple purposes including fire protection, stock, and small fish pond. With a height of 14 feet and a length of 525 feet, the dam has a maximum storage capacity of 14 acre-feet and a normal storage of 12 acre-feet. Despite its age, the dam has a significant hazard potential and a poor condition assessment, indicating the need for ongoing maintenance and potential upgrades to ensure its safety and integrity.

The dam features an uncontrolled spillway with a width of 50 feet and has a maximum discharge capacity of 1150 cubic feet per second. It is regulated by the New York State Department of Environmental Conservation and undergoes regular inspections, with the last one conducted in April 2019. The dam's risk assessment is rated as moderate, highlighting the importance of implementing proper risk management measures to mitigate potential hazards and protect surrounding areas from flooding or other safety concerns. Overall, Dieterich Dam #2 is a vital structure for local water resource management and climate resilience efforts in Dutchess County, New York.

As a privately owned dam, Dieterich Dam #2 plays a crucial role in providing essential water services for the community while also posing a significant risk due to its poor condition and aging infrastructure. It is important for the dam's owners to work closely with regulatory agencies and implement necessary maintenance and upgrades to ensure its long-term stability and safety. With its rich history and functional importance, the dam serves as a reminder of the ongoing challenges and opportunities in managing water resources and adapting to changing climate conditions in the region.

Year Completed

1910

Dam Length

525

Dam Height

14

River Or Stream

MILL BROOK

Primary Dam Type

Masonry

Surface Area

3

Nid Storage

14

Hazard Potential

Significant

Nid Height

14
       
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.