Willow Creek Flowage No 1 Reservoir Report

Last Updated: December 6, 2025

Located in Chippewa, Wisconsin, Willow Creek Flowage No 1 is a state-regulated earth dam completed in 1966 for the primary purpose of serving as a fish and wildlife pond.


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Summary

With a structural height of 8.8 feet and a length of 200 feet, the dam has a maximum storage capacity of 67 acre-feet and covers a surface area of 28 acres. The dam is equipped with a controlled spillway measuring 37 feet wide to manage a maximum discharge of 145 cubic feet per second.

Despite being classified as having a low hazard potential and fair condition assessment, the dam is situated in an area with a very high risk assessment ranking. The emergency action plan for Willow Creek Flowage No 1 was last revised in 2014, with inspections occurring every 10 years. The regulatory oversight for the dam falls under the Wisconsin Department of Natural Resources, ensuring that the structure is regularly inspected, permitted, and enforced to meet state standards.

Willow Creek Flowage No 1 serves as a vital habitat for local fish and wildlife, while also providing recreational opportunities for outdoor enthusiasts. With its strategic location and purposeful design, this earth dam showcases the intersection of water resource management and climate adaptation efforts in Wisconsin's diverse ecosystem.

Year Completed

1966

Dam Length

200

Dam Height

8.8

River Or Stream

Willow Creek

Primary Dam Type

Earth

Surface Area

28

Drainage Area

1.1

Nid Storage

67

Structural Height

8.8

Hazard Potential

Low

Nid Height

9
       
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.