Big Stone Lake Reservoir Report
Nearby: Ortonville Twp 15 Odessa Twp North 25
Last Updated: December 13, 2025
Big Stone Lake in Minnesota is a state-regulated water resource located along the Minnesota River, with a dam completed in 1937 by the Works Progress Administration (WPA-CW).
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Summary
The dam stands at a height of 15 feet and has a maximum storage capacity of 205,000 acre-feet, serving as a vital source for water management in the region. With a surface area of 12,094 acres and a drainage area of 1,182 square miles, the lake plays a crucial role in maintaining water levels and regulating flow downstream.
The Big Stone Lake dam, with a spillway width of 77 feet, has a significant hazard potential and is classified in fair condition as of the last assessment in 2008. Inspections are conducted regularly, with the last inspection in August 2019, highlighting the commitment to ensuring the safety and integrity of the structure. The lake's primary purpose is listed as "Other," indicating its multifaceted role in water resource management, with a normal storage capacity of 100,880 acre-feet and a maximum discharge rate of 5,600 cubic feet per second.
Located in Ortonville, Big Stone Lake is a key water resource managed by the Minnesota Department of Natural Resources (MNDNR EWR) to meet various regulatory standards. The dam's construction and operation are overseen by state agencies, reflecting a comprehensive approach to water resource management and climate resilience in the region. Enthusiasts of water resources and climate trends will find Big Stone Lake an intriguing case study in sustainable water management practices and the complexities of balancing environmental protection and human needs in a changing climate.
Year Completed |
1937 |
Dam Length |
6300 |
Dam Height |
15 |
River Or Stream |
MINNESOTA RIVER |
Primary Dam Type |
Other |
Surface Area |
12094 |
Hydraulic Height |
6 |
Drainage Area |
1182 |
Nid Storage |
205000 |
Structural Height |
14 |
Hazard Potential |
Significant |
Foundations |
Unlisted/Unknown |
Nid Height |
15 |
Seasonal Comparison
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Nearby Streamflow Levels
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.
Big Stone Lake