Johnson Pool Reservoir Report

Last Updated: December 6, 2025

Johnson Pool is a private dam located in Freeborn County, Minnesota, designed by the USDA NRCS and completed in 1970.


°F

°F

mph

Wind

%

Humidity

Summary

The primary purpose of this rockfill dam is flood risk reduction along Turtle Creek-TR. With a structural height of 20 feet and a length of 500 feet, Johnson Pool provides a storage capacity of 1454 acre-feet and covers a surface area of 77 acres.

Managed by the MNDNR EWR, Johnson Pool has a low hazard potential and a fair condition assessment as of the last inspection in 2013. The dam features uncontrolled spillways and outlet gates, with a maximum discharge capacity of 25 cubic feet per second. Even though the risk assessment is moderate, the dam meets regulatory standards with state permitting, inspection, and enforcement in place to ensure its safety and functionality for water resource management in the region.

Overall, Johnson Pool serves as a vital infrastructure for flood risk reduction in the area, providing storage capacity, discharge control, and regulatory compliance to protect the surrounding communities from potential water-related hazards. As climate enthusiasts and water resource stakeholders, understanding the design, purpose, and management of dams like Johnson Pool is essential for sustainable water management practices and climate resilience initiatives in the region.

Year Completed

1970

Dam Length

500

Dam Height

17

River Or Stream

TURTLE CREEK-TR

Primary Dam Type

Rockfill

Surface Area

77

Drainage Area

1

Nid Storage

1454

Structural Height

20

Outlet Gates

Uncontrolled

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

20
       
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.