Afton Reservoir Report

Last Updated: December 6, 2025

Afton, located in Rock, Wisconsin, is a privately owned dam on Bass Creek completed in 1952 for recreational purposes.


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Summary

The gravity dam stands at a height of 9 feet with a hydraulic height of 6 feet, providing a normal storage capacity of 80 acre-feet and a maximum discharge of 3850 cubic feet per second. With a hazard potential rated as significant and a risk assessment indicating a very high risk level, the dam is regulated by the Wisconsin Department of Natural Resources, with regular inspections and enforcement ensuring its safety and compliance with state regulations.

Despite its age, Afton Dam continues to serve as a vital recreational resource in the area, offering a surface area of 30 acres and a drainage area of 65 square miles for outdoor enthusiasts to enjoy. However, the dam's condition assessment remains unrated, highlighting the need for further evaluation and potential maintenance to mitigate any safety concerns. With a risk management plan yet to be implemented and emergency action preparedness status unclear, stakeholders are encouraged to stay informed about the dam's status and be prepared for any potential emergencies that may arise.

As a key component of the local water resource infrastructure, Afton Dam plays a crucial role in managing water flow and providing recreational opportunities for the community. With its controlled spillway and significant hazard potential, ongoing monitoring and maintenance are essential to ensure the dam's continued functionality and safety for both residents and visitors alike. As water resource and climate enthusiasts, it is important to stay engaged with the management of Afton Dam and advocate for responsible stewardship of this important natural resource.

Year Completed

1952

Dam Length

250

Dam Height

9

River Or Stream

BASS CREEK

Primary Dam Type

Gravity

Surface Area

30

Hydraulic Height

6

Drainage Area

65

Nid Storage

200

Structural Height

9

Hazard Potential

Significant

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.