Morley Dam Reservoir Report

Last Updated: December 5, 2025

Morley Dam, also known as Frank Deyo Dam, is a gravity dam located on the Little Muskegon River in Morley, Michigan.


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Summary

Built in 1908, this dam serves primarily for recreational purposes, offering a surface area of 57 acres and a maximum storage capacity of 600 acre-feet. With a height of 22 feet and a length of 460 feet, Morley Dam plays a crucial role in regulating the flow of the river and providing water storage for the surrounding area.

Managed by the local government and regulated by the Michigan Department of Environment, Great Lakes, and Energy (DEGLE), Morley Dam has a significant hazard potential but is currently assessed as being in satisfactory condition. The dam features a controlled spillway with a width of 64 feet to manage excess water flow, and has a maximum discharge capacity of 3,375 cubic feet per second. Despite its age, Morley Dam continues to be inspected regularly to ensure its structural integrity and safety for nearby residents and recreational users.

With a very high risk assessment rating of 1, Morley Dam requires vigilant risk management measures to mitigate potential hazards and ensure public safety. The dam's emergency action plan, last revised in 2013, serves as a guideline for responding to any unforeseen events or emergencies. As a historic structure that significantly impacts the local water resources and climate, Morley Dam remains a key focal point for water resource and climate enthusiasts in the Mecosta County area.

Year Completed

1908

Dam Length

460

Dam Height

22

River Or Stream

Little Muskegon River

Primary Dam Type

Gravity

Surface Area

57

Hydraulic Height

22

Drainage Area

157

Nid Storage

600

Structural Height

22

Hazard Potential

Significant

Nid Height

22
       
Seasonal Comparison

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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.