Johnson-6 Dam Reservoir Report
Nearby: Lake Thunderhead Dam Phantom Lake Dam
Last Updated: December 12, 2025
Johnson-6 Dam, also known as Johnson Lake Dam #6, is a private structure located in Martinstown, Missouri, along the Chariton River.
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Summary
Completed in 1985, this earth dam stands at a height of 20 feet and serves primarily for flood risk reduction. With a storage capacity of 53 acre-feet and a surface area of 5 acres, the dam is designed to protect the surrounding area from potential flooding events.
Despite its low hazard potential, Johnson-6 Dam plays a crucial role in maintaining the safety and stability of the Chariton River watershed. The dam's uncontrolled spillway and stone core construction reflect its focus on flood risk reduction and grade stabilization. While not currently rated for condition assessment, the dam's moderate risk level underscores the importance of ongoing monitoring and maintenance to ensure its effectiveness in mitigating flood impacts in the region.
Managed by a private owner, Johnson-6 Dam is not regulated by the state and does not have a formal emergency action plan in place. However, its strategic location and design features make it a key asset for protecting the community from potential inundation. As water resource and climate enthusiasts, understanding the role of structures like Johnson-6 Dam in managing flood risk and preserving ecosystems highlights the interconnectedness of water management and environmental stewardship in our changing climate.
Year Completed |
1985 |
Dam Length |
350 |
Dam Height |
20 |
River Or Stream |
CHARITON RIVER |
Primary Dam Type |
Earth |
Surface Area |
5 |
Hydraulic Height |
19 |
Drainage Area |
235 |
Nid Storage |
53 |
Structural Height |
21 |
Outlet Gates |
None |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
21 |
Seasonal Comparison
Weather Forecast
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.
Johnson-6 Dam