Sylvan Lake Dam Reservoir Report

Last Updated: December 5, 2025

Sylvan Lake Dam, located in St.


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Summary

Francois, Missouri, is a private earth dam constructed in 1958 for recreational purposes. Standing at a height of 30 feet, the dam has a storage capacity of 209 acre-feet and a surface area of 13 acres. It is situated on TR Allen Branch and is under the jurisdiction of the St. Louis District of the US Army Corps of Engineers.

Despite its primary purpose for recreation, Sylvan Lake Dam poses a high hazard potential due to its condition being labeled as "Not Rated." The dam has not been inspected recently, and there are no emergency action plans in place, raising concerns about its safety and the potential risks it may pose to the surrounding area in the event of a failure.

Given its high hazard potential and lack of recent inspections, there is a pressing need for a thorough assessment of Sylvan Lake Dam to ensure its structural integrity and the safety of the community. Climate and water resource enthusiasts should closely monitor any developments regarding the dam's condition and the implementation of necessary risk management measures to mitigate potential hazards.

Year Completed

1958

Dam Height

30

River Or Stream

TR ALLEN BRANCH

Primary Dam Type

Earth

Surface Area

13

Drainage Area

600

Nid Storage

209

Structural Height

30

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

30
       
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.