Lower 7 Group No. 2 Reservoir Report
Nearby: Lower 7 Group No. 1 Harold Buck Dam
Last Updated: December 6, 2025
Lower 7 Group No.
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Summary
2 is a privately owned flood risk reduction structure located in Zumbrota, Minnesota, along the TR-NO. BRANCH ZUMBRO RIVER. Built in 1971 by the USDA NRCS, this earth dam stands at 20 feet tall and spans 360 feet in length, with a maximum storage capacity of 60 acre-feet. Despite its low hazard potential and moderate risk assessment, the dam's condition remains unrated, highlighting the need for further evaluation and maintenance to ensure its effectiveness in managing flood risks in the region.
With a spillway width of 83 feet and uncontrolled outlet gates, Lower 7 Group No. 2 plays a crucial role in mitigating floodwaters and protecting the surrounding areas from potential inundation. Its stone core and soil foundation contribute to its structural integrity, while its location within the Goodhue County landscape underscores its importance in the local water resource management system. The dam's association with the Natural Resources Conservation Service and its primary purpose of flood risk reduction emphasize the collaborative efforts involved in safeguarding communities and infrastructure from the impacts of extreme weather events.
As climate change continues to exacerbate the frequency and intensity of flooding events, the maintenance and assessment of structures like Lower 7 Group No. 2 become increasingly vital in ensuring the resilience of water resource systems. By understanding the dam's design, purpose, and risk profile, water resource and climate enthusiasts can appreciate the intricate balance between human intervention and natural forces in managing water-related hazards. As such, ongoing monitoring and maintenance efforts will be essential in safeguarding the dam's effectiveness and protecting the local community from the impacts of future flood events.
Year Completed |
1971 |
Dam Length |
360 |
Dam Height |
19 |
River Or Stream |
TR-NO. BRANCH ZUMBRO RIVER |
Primary Dam Type |
Earth |
Surface Area |
4 |
Hydraulic Height |
19 |
Drainage Area |
0.56 |
Nid Storage |
60 |
Structural Height |
20 |
Outlet Gates |
Uncontrolled |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
20 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Cannon River At Welch
|
384cfs |
Mississippi River At Red Wing
|
12400cfs |
South Fork Zumbro River At Rochester
|
85cfs |
Straight River Near Faribault
|
83cfs |
Vermillion River Near Empire
|
40cfs |
Mississippi River At Prescott
|
12900cfs |
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.
Lower 7 Group No. 2