Winslow Lake Reservoir Report

Last Updated: December 8, 2025

Winslow Lake, located in Oconto, Wisconsin, is a private water resource managed by the USDA NRCS and regulated by the Wisconsin Department of Natural Resources.


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Summary

This recreational lake, completed in 1971, serves as a popular spot for outdoor enthusiasts seeking leisure activities such as fishing and boating. With a dam height of 10 feet and a storage capacity of 200 acre-feet, Winslow Lake offers a serene escape for visitors to enjoy its 35-acre surface area.

Despite its low hazard potential and fair condition assessment, Winslow Lake has a very high risk assessment rating of 1 due to its location along the First South Branch Oconto River. The dam's controlled spillway and hydraulic height of 6 feet help manage potential flooding issues, with a maximum discharge capacity of 43 cubic feet per second. Regular inspections have been conducted, with the last inspection in May 2012 and a condition assessment update in August 2019. While emergency action plans are not currently in place, the lake remains a picturesque destination for water resource and climate enthusiasts to appreciate and explore.

Year Completed

1971

Dam Length

150

Dam Height

10

River Or Stream

FIRST SOUTH BRANCH OCONTO

Primary Dam Type

Earth

Surface Area

35

Hydraulic Height

6

Drainage Area

0.3

Nid Storage

200

Structural Height

10

Hazard Potential

Low

Nid Height

10
       
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.