Rynearson Dam No. 2 Reservoir Report

Last Updated: December 13, 2025

Rynearson Dam No.


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Summary

2, located in Necedah, Wisconsin, is a Federal-owned earth dam that was completed in 1939. Managed by the Fish and Wildlife Service, the primary purpose of this dam is to create a fish and wildlife pond, providing essential habitat for local species. With a height of 20 feet and a length of 2877 feet, the dam has a normal storage capacity of 1360 acre-feet and covers a surface area of 680 acres.

This dam is associated with the Branch of Little Yellow Creek and is regulated at the state level, with permitting and enforcement responsibilities falling under the jurisdiction of the state agency. The dam has a low hazard potential and is in satisfactory condition as of the last inspection in July 2018. With a history of modifications and major rehabilitation in 2002, Rynearson Dam No. 2 continues to serve its purpose of supporting fish and wildlife in the region while also contributing to local water resource management efforts.

Water resource and climate enthusiasts will appreciate the vital role that Rynearson Dam No. 2 plays in maintaining the ecological balance of the area, providing a reliable water source for wildlife and contributing to the overall health of the ecosystem. With its strategic location in Juneau County, this dam serves as a key component in the management of water resources and flood control measures in the region. As a Federal-owned structure, it exemplifies the collaborative efforts between government agencies to ensure the sustainability and resilience of water infrastructure in Wisconsin.

Years Modified

2001 - Foundation, 2001 - Hydraulic, 2001 - Mechanical, 2001 - Structural, 2003 - Foundation

Year Completed

1939

Dam Length

2877

Dam Height

20

River Or Stream

BRANCH OF LITTLE YELLOW CREEK

Primary Dam Type

Earth

Surface Area

680

Hydraulic Height

18

Drainage Area

24.93

Nid Storage

9220

Structural Height

20

Outlet Gates

Other Controlled

Hazard Potential

Low

Foundations

Soil

Nid Height

20
       
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.