Boltonville Reservoir Report

Last Updated: December 5, 2025

Boltonville, located in Washington County, Wisconsin, is home to a gravity dam on Stony Creek that was completed in 1848 for recreational purposes.


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Summary

The dam stands at a height of 12 feet and has a hydraulic height of 8 feet, with a storage capacity of 50 acre-feet. With a low hazard potential and fair condition assessment, the dam is considered to have a moderate risk level, according to the data available.

Managed by a private owner, Boltonville Dam is regulated by the Wisconsin Department of Natural Resources (WIDNR), with state jurisdiction and permitting in place. The dam has been inspected periodically, with the last assessment conducted in May 2020. Despite its age, the dam has been modified in 1964 and continues to serve its purpose effectively for recreation, covering a surface area of 9 acres and a drainage area of 16 square miles.

For water resource and climate enthusiasts, Boltonville Dam offers a glimpse into historical dam construction and management practices in Wisconsin. With its picturesque location and recreational significance, the dam plays a vital role in the local ecosystem and provides opportunities for outdoor enjoyment. Keeping a close eye on the dam's condition and risk level is essential for ensuring the safety and sustainability of this valuable water resource in Boltonville.

Years Modified

1964 - Other

Year Completed

1848

Dam Length

200

Dam Height

12

River Or Stream

STONY CREEK

Primary Dam Type

Gravity

Surface Area

9

Hydraulic Height

8

Drainage Area

16

Nid Storage

50

Structural Height

12

Hazard Potential

Low

Nid Height

12
       
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.