Big Falls Reservoir Report

Last Updated: December 5, 2025

Big Falls in Ladysmith, Wisconsin, is a gravity dam completed in 1923 primarily for hydroelectric power generation and recreation purposes.


°F

°F

mph

Wind

%

Humidity

Summary

With a height of 50 feet and a length of 2196 feet, the dam has a storage capacity of 4000 acre-feet and a maximum discharge of 91000 cubic feet per second. The dam sits on the Flambeau River within the Detroit District and is regulated by the Federal Energy Regulatory Commission.

This dam presents a high hazard potential due to its size and location, with a very high risk assessment rating. Despite its age, the condition assessment of the dam is not available, and it has not been inspected since September 2020. The dam features a controlled spillway with a width of 320 feet and eight Tainter radial outlet gates. The surrounding area has a surface area of 369 acres and a drainage area of 1786 square miles, making it a critical water resource and climate management site.

For water resource and climate enthusiasts, Big Falls offers a fascinating glimpse into the engineering marvels of early 20th-century hydroelectric infrastructure. Its historic significance, combined with its vital role in power generation and water management, makes it a site worth studying and appreciating. As climate change continues to impact water resources, understanding and maintaining structures like Big Falls will be crucial for ensuring a sustainable future for generations to come.

Year Completed

1923

Dam Length

2196

Dam Height

50

River Or Stream

Flambeau

Primary Dam Type

Gravity

Surface Area

369

Drainage Area

1786

Nid Storage

4000

Outlet Gates

Tainter (radial) - 8

Hazard Potential

High

Foundations

Rock

Nid Height

50
       
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.