Swelstad Reservoir Report

Last Updated: December 13, 2025

Swelstad, Jack is a private water resource in Marinette, Wisconsin, regulated by the Wisconsin Department of Natural Resources.


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Summary

Situated along the tributary to the South Branch of the Penbenowan River, this dam stands at a height of 21.1 feet with a hydraulic height of 16.1 feet. It has a storage capacity of 555 acre-feet, providing critical water supply for the surrounding area.

Despite being classified as a low hazard potential structure, Swelstad, Jack received a fair condition assessment in 2015. The dam has a surface area of 29.5 acres and a drainage area of 0.5 square miles, contributing to its important role in managing water resources in the region. The last inspection took place in November 2013, with a scheduled frequency of every 10 years to ensure its continued safety and functionality.

With its strategic location and modest storage capacity, Swelstad, Jack serves as a key water resource in Marinette County. As climate change impacts water availability and quality, monitoring and maintaining structures like this dam are crucial for sustainable water management in the region. Enthusiasts of water resources and climate resilience will find Swelstad, Jack to be an intriguing case study in the intersection of infrastructure, regulation, and environmental stewardship.

Dam Height

21.1

River Or Stream

TRIB TO S BR PENBENOWAN RIVER

Surface Area

29.5

Hydraulic Height

16.1

Drainage Area

0.5

Nid Storage

555

Structural Height

21.1

Hazard Potential

Low

Nid Height

21
       
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.