Longan Lake Dam Reservoir Report
Nearby: Dale Deraps Lake Lake Imhoff Dam
Last Updated: December 23, 2025
Longan Lake Dam, located in Marion, Missouri, was completed in 1971 and serves multiple purposes including fire protection, stock, and small fish pond, as well as recreation.
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Summary
The private dam is classified as an earth dam with a height of 33 feet and a storage capacity of 88 acre-feet. It is situated on Moniteau Creek and falls under the jurisdiction of the St. Louis District. Despite being privately owned, the dam is not regulated by the state and has a low hazard potential.
The dam has a surface area of 5 acres and a drainage area of 25 square miles. While it has not been rated for its condition, it has not undergone any recent modifications and is considered to be in a stable state. It does not have an emergency action plan in place, but its low hazard potential suggests a lower risk of failure. With its tranquil setting and multiple uses, Longan Lake Dam stands as a testament to the importance of water resource management and climate considerations in the region.
Year Completed |
1971 |
Dam Height |
33 |
River Or Stream |
TR--MONITEAU CREEK |
Primary Dam Type |
Earth |
Surface Area |
5 |
Drainage Area |
25 |
Nid Storage |
88 |
Structural Height |
33 |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
33 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Hinkson Creek At Columbia
|
1cfs |
Missouri River At Jefferson City
|
29200cfs |
Moreau River Near Jefferson City
|
16cfs |
Missouri River At Boonville
|
28300cfs |
Osage River Below St. Thomas
|
1210cfs |
Lamine River Near Otterville
|
13cfs |
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.
Longan Lake Dam