Cornish Flowage Reservoir Report

Last Updated: December 5, 2025

Cornish Flowage, located in Aitkin, Minnesota, is a state-regulated dam completed in 1976 for the primary purpose of flood risk reduction.


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Summary

Managed by the Minnesota Department of Natural Resources, this rockfill dam stands at a height of 8 feet with a structural height of 9 feet and a length of 38 feet. With a storage capacity of 2000 acre-feet and a surface area of 300 acres, it plays a crucial role in controlling the flow of the Savannah River-TR.

The dam's condition is assessed as fair with a low hazard potential, and it undergoes inspections every 8 years to ensure its safety and integrity. The surrounding area benefits from its flood protection measures, with a maximum discharge capacity of 30 cubic feet per second. Despite its modest size and capacity, Cornish Flowage serves as a vital infrastructure for water resource management in the region, contributing to the overall resilience of the community against potential flooding events. Enthusiasts of water resources and climate would find this dam's design and purpose intriguing, highlighting the intersection of engineering, environmental conservation, and disaster risk reduction.

Year Completed

1976

Dam Length

38

Dam Height

8

River Or Stream

SAVANNAH RIVER-TR

Primary Dam Type

Rockfill

Surface Area

300

Drainage Area

4.4

Nid Storage

2000

Structural Height

9

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

9
       
Seasonal Comparison

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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.