Fann Detention Reservoir Report

Last Updated: December 5, 2025

Fann Detention, also known as N&H Acres, is a private-owned earth dam located in Fillmore County, Minnesota.


°F

°F

mph

Wind

%

Humidity

Summary

Built by the NRCS in 1993, this structure serves the primary purpose of flood risk reduction along the Root River. Standing at a height of 30 feet and a length of 350 feet, Fann Detention has a storage capacity of 24.3 acre-feet and a maximum discharge of 200 cubic feet per second.

Managed by the Minnesota Department of Natural Resources, Fann Detention has a low hazard potential and is considered to be in satisfactory condition as of its last inspection in June 2017. With a moderate risk assessment rating, this dam is equipped with uncontrolled spillways and gates. Despite its age, the structure continues to play a crucial role in mitigating flood risks in the region, ensuring the safety of nearby communities like Rushford.

As a vital component of flood risk management in Fillmore County, Fann Detention stands as a testament to effective infrastructure design and maintenance. With its strategic location and design features, this earth dam remains a key asset in safeguarding the local environment and residents from potential water-related hazards. Climate enthusiasts and water resource professionals alike can appreciate the significance of Fann Detention in preserving the natural landscape and enhancing resilience to changing weather patterns in Minnesota.

Year Completed

1993

Dam Length

350

Dam Height

30

River Or Stream

ROOT RIVER-TR

Primary Dam Type

Earth

Drainage Area

1

Nid Storage

24.3

Structural Height

34

Outlet Gates

Uncontrolled

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

34
       
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.