Edward Macdowell Dam Reservoir Report

Last Updated: December 19, 2025

Edward MacDowell Dam, located in Peterborough, New Hampshire, was completed in 1950 by the US Army Corps of Engineers with a primary purpose of flood risk reduction.


°F

°F

mph

Wind

%

Humidity

Summary

This earth dam, standing at a height of 63 feet and spanning 1100 feet in length, helps mitigate the risk of catastrophic flooding to the surrounding communities. However, a risk assessment conducted in 2014 classified the dam's hazard potential as high, primarily due to the sizable population living downstream who could be affected in the event of a dam failure.

The risk management measures implemented by the US Army Corps of Engineers include continuous monitoring of the dam's condition, prioritizing activities to mitigate risks, and collaborating with emergency managers and the public to raise awareness and preparedness for potential dam-related emergencies. Despite the low likelihood of failure scenarios such as water seepage or ice jams causing downstream flooding, the consequences could be devastating, with swift and deep floodwaters impacting areas including Peterborough, Bennington, Antrim, Hillsborough, and Concord. The importance of maintaining the dam and updating emergency action plans is crucial to ensuring the safety of those living downstream of Edward MacDowell Dam.

Year Completed

1950

Dam Length

1100

Dam Height

63

River Or Stream

NUBANUSIT BROOK

Primary Dam Type

Earth

Surface Area

165

Hydraulic Height

57

Drainage Area

44

Nid Storage

31600

Structural Height

63

Hazard Potential

High

Foundations

Rock, Soil

Nid Height

63
       
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.