Arpin Reservoir Report

Last Updated: December 5, 2025

Arpin is a hydroelectric dam located in Ladysmith, Wisconsin, along the Chippewa River.


°F

°F

mph

Wind

%

Humidity

Summary

Built in 1913, this gravity dam stands at 12 feet tall and spans 1590 feet in length, with a capacity for storing up to 980 acre-feet of water. The primary purpose of Arpin is to generate hydroelectric power, but it also serves other functions such as providing for fish and wildlife habitat and recreation opportunities.

Managed by the Federal Energy Regulatory Commission, Arpin has a low hazard potential and a moderate risk assessment rating. The dam features uncontrolled spillways and a variety of outlet gates for water release. Despite its age, Arpin has not undergone recent condition assessments, and its emergency action plan status is not available. However, with inspection frequency set at every 3 years, the dam continues to play a vital role in water resource management and energy production in the region.

Climate and water resource enthusiasts will appreciate the historical significance and engineering marvel of Arpin, as it continues to harness the power of the Chippewa River to generate clean energy while providing valuable ecological benefits. While facing moderate risks, the dam remains a key infrastructure for the local community and contributes to the sustainable use of water resources in Sawyer County, Wisconsin.

Year Completed

1913

Dam Length

1590

Dam Height

12

River Or Stream

Chippewa River

Primary Dam Type

Gravity

Surface Area

294

Hydraulic Height

34

Drainage Area

800

Nid Storage

980

Structural Height

16

Outlet Gates

Other Controlled - 2, Tainter (radial) - 2, Vertical Lift - 2

Hazard Potential

Low

Foundations

Rock

Nid Height

34
       
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.