Cranberry Lake Reservoir Report

Last Updated: December 5, 2025

Cranberry Lake, also known as George Von Hoffmann, is a private dam located in Vilas, Wisconsin, near Eagle River.


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Summary

This gravity dam serves primarily for recreational purposes, with a storage capacity of 72 acre-feet and a low hazard potential. The dam stands at a structural height of 8.1 feet and has a hydraulic height of 6 feet, controlling the flow of the Inlet Cranberry Lake.

Despite its fair condition assessment, Cranberry Lake poses a very high risk due to its location and potential impact on the surrounding area. The dam has been inspected periodically, with the last assessment conducted in November 2012. While the dam is regulated, permitted, inspected, and enforced by the Wisconsin Department of Natural Resources, there have been no major modifications or risk management measures implemented to address the identified high risk level.

Enthusiasts of water resources and climate in Wisconsin may find Cranberry Lake an intriguing case study, with its unique design, recreational purpose, and high risk profile. As climate change continues to impact water resources and infrastructure, understanding the management and maintenance of dams like Cranberry Lake becomes increasingly important for ensuring public safety and environmental sustainability in the face of changing hydrological conditions.

Dam Height

8.1

River Or Stream

INLET CRANBERRY LAKE

Primary Dam Type

Gravity

Surface Area

18

Hydraulic Height

6

Drainage Area

0.1

Nid Storage

72

Structural Height

8.1

Hazard Potential

Low

Nid Height

8
       
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.