Little Falls Reservoir Report

Last Updated: December 5, 2025

Little Falls, also known as Upper Power, is a state-owned dam located on the Willow River in St.


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Summary

Croix, Wisconsin. Completed in 1895, this gravity dam stands at 30 feet tall and stretches 370 feet in length, providing a storage capacity of 1700 acre-feet. The dam primarily serves for recreational purposes, offering a surface area of 172 acres for outdoor enthusiasts to enjoy.

With a high hazard potential and fair condition assessment, Little Falls poses a significant risk, especially considering its very high risk assessment rating. Despite regular state inspections and regulatory oversight by the Wisconsin Department of Natural Resources, the dam remains a potential safety concern. Emergency action plans have been prepared, but there is room for improvement in meeting guidelines and ensuring the safety of the surrounding community in the event of a dam failure.

Located just 2 miles from Hudson, Little Falls is not only a historical landmark but also a critical piece of infrastructure in need of careful monitoring and management. As climate change continues to impact water resources and infrastructure, the importance of maintaining and upgrading dams like Little Falls becomes increasingly evident to ensure the safety and sustainability of our water systems.

Years Modified

1920 - Other

Year Completed

1895

Dam Length

370

Dam Height

30

River Or Stream

Willow River

Primary Dam Type

Gravity

Surface Area

172

Hydraulic Height

24

Drainage Area

171

Nid Storage

1700

Structural Height

30

Hazard Potential

High

Nid Height

30
       
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.