Maple Lake Reservoir Report

Last Updated: December 5, 2025

Maple Lake in Oneida, Wisconsin, is a gravity dam completed in 1941 primarily for recreational purposes, offering a surface area of 144 acres and a maximum storage capacity of 1330 acre-feet.


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Summary

The dam stands at a height of 12 feet, with a hydraulic height of 7 feet, and a length of 85 feet. The lake's drainage area is one square mile, with a controlled spillway type and a maximum discharge capacity of 170 cubic feet per second.

Despite its fair condition assessment and high hazard potential, Maple Lake is regulated by the Wisconsin Department of Natural Resources, with state permitting, inspection, and enforcement in place. The dam's emergency action plan status is unclear, but its risk assessment indicates a very high risk level. Located in the Detroit District, Maple Lake's risk management measures and inundation maps are currently unavailable, warranting careful monitoring and maintenance to ensure the safety and sustainability of this water resource for future generations.

Year Completed

1941

Dam Length

85

Dam Height

12

River Or Stream

OUTLET TO TOWN LINE LAKE

Primary Dam Type

Gravity

Surface Area

144

Hydraulic Height

7

Drainage Area

1

Nid Storage

1330

Structural Height

12

Hazard Potential

High

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.