Plainwell Dam #1 Reservoir Report

Last Updated: December 5, 2025

Plainwell Dam #1, located on the Kalamazoo River in Allegan, Michigan, was completed in 1902 and serves a primary purpose of recreation.


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Summary

This gravity dam stands at a height of 21 feet with a hydraulic height of 14.6 feet and a length of 1185 feet. It has a normal storage capacity of 490 acre-feet and a maximum discharge of 5800 cubic feet per second. The spillway, which is uncontrolled, has a width of 335 feet.

Despite being classified as having a low hazard potential and a moderate risk assessment, Plainwell Dam #1 has not been rated for its condition. The last inspection took place in 2004, with a scheduled inspection frequency of every five years. However, the emergency action plan (EAP) was last revised in 2007, indicating a potential need for updated emergency protocols. The dam is not regulated by the state and does not have associated locks or outlet gates.

For water resource and climate enthusiasts, Plainwell Dam #1 offers a glimpse into the historical engineering feats that have shaped Michigan's water infrastructure. Its location on the Kalamazoo River provides opportunities for recreational activities, but the lack of recent condition assessments and emergency preparedness updates raise concerns about its long-term safety and maintenance. As discussions around water resource management and climate resilience continue to evolve, Plainwell Dam #1 serves as a reminder of the importance of proactive monitoring and risk mitigation for aging infrastructure.

Year Completed

1902

Dam Length

1185

Dam Height

21

River Or Stream

Kalamazoo River

Primary Dam Type

Gravity

Surface Area

56

Hydraulic Height

14.6

Drainage Area

1299

Nid Storage

1460

Structural Height

21

Hazard Potential

Low

Nid Height

21
       
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.