Middleville Reservoir Report

Last Updated: December 5, 2025

Middleville is a hydroelectric dam located on the Thornapple River in Michigan.


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Summary

Built in 1940, this earth and gravity dam stands at a height of 15 feet and spans 166 feet in length. With a storage capacity of 270 acre-feet and a drainage area of 557 square miles, Middleville plays a crucial role in harnessing the power of water for energy generation.

Managed by the Federal Energy Regulatory Commission, Middleville's dam serves a primary purpose of hydroelectric power generation. Its controlled spillway and other controlled outlet gates ensure the safe release of water, with a maximum discharge rate of 3200 cubic feet per second. Despite its low hazard potential, Middleville is subject to regular inspections and has a risk assessment rating of "Very High (1)", highlighting the importance of effective risk management measures in safeguarding this vital water resource.

Middleville's strategic location, efficient design, and significant storage capacity make it a key player in water resource management and climate sustainability efforts. Its role in hydroelectric power generation underscores the intersection of water infrastructure and renewable energy production, highlighting the importance of maintaining and monitoring dams like Middleville to ensure both water security and environmental resilience in the face of changing climate conditions.

Year Completed

1940

Dam Length

166

Dam Height

15

River Or Stream

Thornapple River

Surface Area

30

Drainage Area

557

Nid Storage

270

Outlet Gates

Other Controlled - 1

Hazard Potential

Low

Foundations

Soil

Nid Height

15
       
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.