Twin Parks 4 Reservoir Report

Last Updated: December 5, 2025

Twin Parks 4, also known as Prazak's, is a local government-owned dam located in Iowa, Wisconsin.


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Summary

Built in 1965 by the USDA NRCS, this earth dam stands at a height of 30.8 feet and serves the primary purpose of flood risk reduction along the TR Mill Creek. With a storage capacity of 178 acre-feet and a maximum discharge of 110 cubic feet per second, Twin Parks 4 plays a crucial role in managing water flow and protecting the surrounding area from potential flood hazards.

The dam is regulated by the Wisconsin Department of Natural Resources (WIDNR) and undergoes regular inspections to ensure its structural integrity and functionality. Despite being classified as having a high hazard potential, Twin Parks 4 is currently assessed to be in fair condition as of the last assessment in May 2020. The dam features an uncontrolled spillway with a width of 40 feet and covers a surface area of 5 acres, providing vital debris control and flood risk reduction benefits to the community.

Located in a picturesque setting with a moderate risk assessment rating, Twin Parks 4 stands as a testament to effective water resource management and climate resilience efforts in Wisconsin. As water resource and climate enthusiasts, it is essential to recognize the importance of infrastructure like Twin Parks 4 in safeguarding our communities and natural habitats against the impacts of extreme weather events and flooding.

Year Completed

1965

Dam Length

448

Dam Height

30.8

River Or Stream

TR MILL CREEK

Primary Dam Type

Earth

Surface Area

5

Hydraulic Height

13.2

Drainage Area

2

Nid Storage

178

Structural Height

30.8

Hazard Potential

High

Nid Height

31
       
Seasonal Comparison

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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.