Dieterich Dam #3 Reservoir Report

Last Updated: December 6, 2025

Dieterich Dam #3, also known as Dieterich Pond, is a private-owned structure situated in Millbrook, New York, along the Wappinger Creek.


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Summary

Built in 1910, this masonry dam stands at 14 feet high and spans 55 feet in length, serving primarily for irrigation purposes. With a storage capacity of 200 acre-feet, including a normal storage level of 110 acre-feet, the dam covers a surface area of 31 acres and drains a 12.6 square mile watershed area.

The dam's spillway, which is uncontrolled and 50 feet wide, can handle a maximum discharge of 925 cubic feet per second. Despite being rated as having a significant hazard potential, the dam's condition assessment remains unrated. Regular inspections are conducted, with the last one taking place in November 2020, following a frequency of 4 inspections per year. The risk assessment for Dieterich Dam #3 is moderate (3), indicating a need for ongoing risk management measures to ensure the safety and stability of the structure.

Located in Dutchess County, New York, this historic dam is regulated by the New York State Department of Environmental Conservation, with enforcement, permitting, and inspection responsibilities falling under state jurisdiction. With its rich history and vital role in the local irrigation network, Dieterich Dam #3 stands as a testament to the importance of water resource management and climate resilience in the region.

Year Completed

1910

Dam Length

55

Dam Height

14

River Or Stream

WAPPINGER CREEK

Primary Dam Type

Masonry

Surface Area

31

Drainage Area

12.6

Nid Storage

200

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.