Manhan River Dam Reservoir Report

Last Updated: December 6, 2025

The Manhan River Dam, located in Easthampton, Massachusetts, was completed in 1998 for the primary purpose of recreation.


°F

°F

mph

Wind

%

Humidity

Summary

This concrete dam stands at a height of 16 feet and has a hydraulic height of 8 feet, offering a surface area of 1.7 acres for water activities. With a normal storage capacity of 30 acre-feet and a maximum storage of 150 acre-feet, the dam plays a crucial role in providing water resources for the surrounding area.

Managed by the Department of Conservation and Recreation, the Manhan River Dam is regulated by the state of Massachusetts and undergoes regular inspections to ensure its structural integrity. While the dam is rated as having a fair condition assessment, its hazard potential is considered significant, emphasizing the importance of ongoing risk management measures. With a drainage area of 69 square miles, the dam serves as a vital resource for water supply and flood control in the region.

As part of the New England District, the Manhan River Dam serves as a key component in the local water infrastructure, contributing to the overall resilience and sustainability of the surrounding ecosystem. Its presence not only offers recreational opportunities but also plays a critical role in water management and conservation efforts in the Hampshire County area.

Year Completed

1998

Dam Length

115

Dam Height

16

River Or Stream

MANHAN RIVER

Primary Dam Type

Concrete

Surface Area

1.7

Hydraulic Height

8

Drainage Area

69

Nid Storage

150

Hazard Potential

Significant

Foundations

Unlisted/Unknown

Nid Height

16
       
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.