Johnson Lake Dam Reservoir Report

Last Updated: December 19, 2025

Johnson Lake Dam in Carroll, Missouri, stands as a vital structure for fire protection, stock, and small fish pond management.


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Summary

Completed in 1955, this earth dam boasts a height of 25 feet and a storage capacity of 94 acre-feet, with a normal storage level of 54 acre-feet. Serving multiple purposes including recreation, Johnson Lake Dam serves as an offstream barrier for Standley Branch, offering a surface area of 7 acres for water enthusiasts to enjoy.

Despite its age, Johnson Lake Dam has a high hazard potential due to its condition being not rated and the last inspection dating back to 1980. With no state regulation or enforcement in place, this privately owned dam poses significant risks to the surrounding area in case of a breach or failure. Emergency action plans and risk assessments are lacking, raising concerns about the safety and management of this crucial water resource in the region.

As water resource and climate enthusiasts, the data on Johnson Lake Dam highlights the importance of regular inspection, maintenance, and emergency preparedness for dams to mitigate potential risks and ensure the safety of communities downstream. With its outdated infrastructure and lack of oversight, Johnson Lake Dam serves as a reminder of the need for proactive measures to safeguard our water resources and adapt to the changing climate conditions that may impact dam safety in the future.

Year Completed

1955

Dam Height

25

River Or Stream

OFFSTREAM STANDLEY BRANCH

Primary Dam Type

Earth

Surface Area

7

Drainage Area

32

Nid Storage

94

Structural Height

25

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

25
       
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.