Flat Lake Reservoir Report
Last Updated: December 5, 2025
Flat Lake, located in Becker County, Minnesota, is a gravity-type dam completed in 1941 with a primary purpose of "Other." The dam stands at a height of 6 feet and has a structural height of 8 feet, with a length of 330 feet.
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Summary
It has a normal storage capacity of 5020 acre-feet and a maximum storage of 12100 acre-feet, serving a drainage area of 33.5 square miles. The reservoir covers a surface area of 1754 acres and is situated on the Egg River.
With a low hazard potential and a condition assessment of "Not Rated," Flat Lake dam has not been inspected recently and has an inspection frequency of 8 years. While the dam does not have an Emergency Action Plan (EAP) prepared, it meets guidelines for risk management measures. Despite being federally owned, there are no associated federal agencies for funding, design, construction, regulation, inspections, or operations. This picturesque reservoir is a vital water resource in the region, serving various purposes while maintaining a low risk profile for the surrounding community and environment.
Year Completed |
1941 |
Dam Length |
330 |
Dam Height |
6 |
River Or Stream |
EGG RIVER |
Primary Dam Type |
Gravity |
Surface Area |
1754 |
Drainage Area |
33.5 |
Nid Storage |
12100 |
Structural Height |
8 |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
8 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Straight River Near Park Rapids
|
46cfs |
Buffalo River Near Hawley
|
24cfs |
Wild Rice River At Twin Valley
|
85cfs |
Crow Wing River At Nimrod
|
279cfs |
Otter Tail River Near Elizabeth
|
111cfs |
Buffalo River Near Dilworth
|
84cfs |
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.
Flat Lake