Lake Diane Dam Reservoir Report

Last Updated: December 5, 2025

Lake Diane Dam, also known as Goforth Lake Dam, is a private structure located in Hillsdale, Michigan, near Pioneer Ohio.


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Summary

Constructed in 1966, it serves primarily for recreational purposes, offering a surface area of 290 acres and a drainage area of 4.3 square miles. With a height of 19.4 feet and a maximum storage capacity of 3200 acre-feet, this earth-type dam plays a crucial role in managing water resources and supporting outdoor activities in the region.

Despite its recreational focus, Lake Diane Dam is regulated by the state of Michigan and subject to regular inspections to ensure its safety and efficiency. The dam features a controlled spillway with a width of 6 feet, helping to manage water discharge during peak flow events. With a hazard potential rated as significant and a risk assessment indicating a very high risk level, the authorities are attentive to implementing risk management measures and emergency action plans to protect the surrounding communities and environment.

In the event of any potential hazards or emergencies, the dam's condition has been assessed as satisfactory, and appropriate measures are in place to mitigate risks. As a significant structure in the region, Lake Diane Dam stands as a vital component of the local water resource management system, contributing to the ecological balance and recreational opportunities for residents and visitors alike.

Year Completed

1966

Dam Length

190

Dam Height

19.4

River Or Stream

Tributary to Clark Fork Creek

Primary Dam Type

Earth

Surface Area

290

Hydraulic Height

17.1

Drainage Area

4.3

Nid Storage

3200

Structural Height

19.4

Hazard Potential

Significant

Nid Height

19
       
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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.