Lake Ossawinnamakee Reservoir Report

Last Updated: December 5, 2025

Lake Ossawinnamakee, also known as Pelican Brook, is a gravity dam located in Minnesota's Crow Wing County.


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Summary

Built in 1937 by the Works Progress Administration (WPA-C), this dam serves as a crucial water resource for the region, with a normal storage capacity of 8,812 acre-feet and a maximum storage capacity of 10,744 acre-feet. The dam has a structural height of 10 feet and a hydraulic height of 1.9 feet, creating a surface area of 662 acres and serving a drainage area of 47.2 square miles.

Managed by the Minnesota Department of Natural Resources, Lake Ossawinnamakee's dam is regulated, inspected, and enforced by state authorities to ensure its safety and functionality. The dam's spillway, controlled by a width of 20 feet, helps manage water discharge, with a low hazard potential and a satisfactory condition assessment. Despite its significant storage capacity and importance for the local ecosystem, the dam poses a very high risk due to its age and potential for failure, requiring vigilant risk management and monitoring to prevent any emergencies.

With its historical significance and vital role in managing water resources in the region, Lake Ossawinnamakee stands as a testament to the importance of dam infrastructure for climate resilience. As climate change continues to impact water availability and quality, sustainable management of dams like Lake Ossawinnamakee will be crucial for ensuring water security and resilience in the face of evolving climate threats.

Year Completed

1937

Dam Length

48

Dam Height

10

River Or Stream

PELICAN BROOK

Primary Dam Type

Gravity

Surface Area

662

Hydraulic Height

1.9

Drainage Area

47.2

Nid Storage

10744

Structural Height

10

Hazard Potential

Low

Foundations

Unlisted/Unknown

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.