Menasha Dam Reservoir Report

Last Updated: December 5, 2025

Menasha Dam, also known as Otsego City Dam, is a gravity dam located on the Kalamazoo River in Allegan, Michigan.


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Summary

Constructed in 1886, this historic dam serves primarily for hydroelectric power generation and recreational purposes, with a height of 22 feet and a length of 180 feet. The dam has a storage capacity of 700 acre-feet, with a normal storage level of 300 acre-feet, covering a surface area of 73 acres.

Managed by the local government, Menasha Dam is regulated, permitted, inspected, and enforced by the Michigan Department of Environment, Great Lakes, and Energy (DEGLE). Despite being rated as having a high hazard potential, the dam's condition is assessed as fair, with the last inspection conducted in October 2019. The dam features an uncontrolled spillway with a width of 150 feet, and it poses a moderate risk as per the risk assessment conducted.

With its rich history, dual-purpose functionality, and essential role in water resource management and renewable energy generation, Menasha Dam stands as a significant landmark on the Kalamazoo River. Its presence not only contributes to the local community's power needs but also offers recreational opportunities while being closely monitored and managed to ensure safety and environmental protection.

Year Completed

1886

Dam Length

180

Dam Height

22

River Or Stream

Kalamazoo River

Primary Dam Type

Gravity

Surface Area

73

Hydraulic Height

21.6

Drainage Area

1415

Nid Storage

700

Structural Height

22

Hazard Potential

High

Nid Height

22
       
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.