Mill Creek 3 Reservoir Report

Last Updated: December 5, 2025

Mill Creek 3, also known as Ewers, is a local government-owned earth dam located in Boaz, Wisconsin, along Core Hollow Creek.


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Summary

Built in 1961 by USDA NRCS, this flood risk reduction structure stands at a height of 31 feet and has a hydraulic height of 16 feet. With a storage capacity of 135 acre-feet and a drainage area of 2 square miles, this dam plays a crucial role in debris control and flood risk reduction in the area.

Despite its age, Mill Creek 3 is well-maintained, with a fair condition assessment as of September 2020. The dam has a low hazard potential and is inspected every 10 years to ensure its structural integrity and functionality. Managed by the WIDNR, this dam has a moderate risk assessment rating, indicating the importance of continued monitoring and risk management measures to safeguard against potential hazards. The dam's uncontrolled spillway and overall design contribute to its effectiveness in managing water flow and reducing flood risks in the region.

For water resource and climate enthusiasts, Mill Creek 3 serves as a prime example of successful flood risk reduction infrastructure in Wisconsin. Its strategic location, design features, and regulatory oversight by the WIDNR highlight the importance of efficient water management practices in mitigating potential hazards and safeguarding communities against the impacts of extreme weather events. As climate change continues to pose challenges for water resources, structures like Mill Creek 3 play a crucial role in enhancing resilience and protecting vulnerable areas from the adverse effects of floods.

Year Completed

1961

Dam Length

680

Dam Height

31

River Or Stream

CORE HOLLOW CREEK

Primary Dam Type

Earth

Surface Area

1

Hydraulic Height

16

Drainage Area

2

Nid Storage

135

Structural Height

31

Hazard Potential

Low

Nid Height

31
       
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.