Long Lake Reservoir Report
Nearby: Birch Lake Bear Lake
Last Updated: December 5, 2025
Long Lake, located in Washburn, Wisconsin, is a gravity dam completed in 1913 for recreational purposes, offering a surface area of 3290 acres and a maximum storage capacity of 35,000 acre-feet.
°F
°F
mph
Wind
%
Humidity
Summary
This picturesque lake is regulated by the Wisconsin Department of Natural Resources and boasts a controlled spillway type with a hydraulic height of 7 feet and a structural height of 15 feet. With a drainage area of 82 square miles and a maximum discharge of 2660 cubic feet per second, Long Lake provides a serene setting for water resource and climate enthusiasts to explore and enjoy.
Despite its fair condition assessment and high hazard potential, Long Lake remains a popular destination for outdoor recreation, attracting visitors with its scenic beauty and abundant water activities. The dam's emergency action plan, last revised in 2012, helps mitigate risks associated with its very high hazard potential rating. With a history of modification in 1992 and regular inspections every two years, Long Lake is closely monitored to ensure public safety and environmental sustainability. As a vital part of the Detroit District, Long Lake stands as a testament to the importance of responsible water resource management in the face of changing climate patterns.
Long Lake's rich history and enduring appeal as a recreational haven underscore the critical role it plays in balancing human enjoyment with the need for effective dam management. As a gravity dam with a significant storage capacity and controlled spillway, Long Lake represents a harmonious blend of natural beauty and engineered infrastructure. With its high hazard potential and very high risk rating, Long Lake serves as a reminder of the challenges and responsibilities inherent in safeguarding water resources in an era of climate uncertainty. For water resource and climate enthusiasts, Long Lake offers a compelling case study in the intersection of human recreation, environmental stewardship, and infrastructure resilience.
Years Modified |
1992 - Other |
Year Completed |
1913 |
Dam Length |
575 |
Dam Height |
15 |
River Or Stream |
BRILL |
Primary Dam Type |
Gravity |
Surface Area |
3290 |
Hydraulic Height |
7 |
Drainage Area |
82 |
Nid Storage |
35000 |
Structural Height |
15 |
Hazard Potential |
High |
Nid Height |
15 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Chippewa River Near Bruce
|
668cfs |
Flambeau River Near Bruce
|
616cfs |
Chippewa River At Bishops Bridge Near Winter
|
251cfs |
Namekagon River At Leonards
|
111cfs |
St. Croix River Near Danbury
|
1650cfs |
Red Cedar River Near Colfax
|
593cfs |
Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
Paiute
Mingo
Tonkawa
Quapaw
Menomonee
Miami
Long Lake
Long Lake -- Access at End Of Sunset Bay Rd