Ralph Hennemann Lake Reservoir Report

Last Updated: December 8, 2025

Ralph Hennemann Lake, located in Scott County, Missouri, was designed by the USDA NRCS and completed in 1992 for the primary purpose of flood risk reduction.


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Summary

This earth dam structure on Ramsey Creek has a height of 25 feet and a hydraulic height of 20 feet, with a storage capacity of 212 acre-feet. The lake covers a surface area of 3 acres and serves multiple purposes including fish and wildlife habitat, flood risk reduction, and recreational activities.

With its uncontrolled spillway and low hazard potential, Ralph Hennemann Lake provides a valuable resource for the local community while also contributing to the overall water management in the area. The dam's structure, made of stone core and soil foundation, has not been rated for its condition assessment, but it stands as a moderate risk (3) according to the risk assessment. Despite not being regulated or inspected by the state, the lake remains a vital part of the watershed, with a drainage area of 128 acres and a maximum discharge capacity of 239 cubic feet per second.

Although Ralph Hennemann Lake does not have outlet gates or associated structures, its presence on Ramsey Creek plays a significant role in managing water flow and mitigating flood risks in the region. As a private-owned reservoir, the lake offers a serene environment for outdoor enthusiasts and serves as a reminder of the importance of sustainable water resource management in the face of changing climate patterns.

Year Completed

1992

Dam Length

386

Dam Height

25

River Or Stream

RAMSEY CREEK

Primary Dam Type

Earth

Surface Area

3

Hydraulic Height

20

Drainage Area

128

Nid Storage

212

Structural Height

23

Outlet Gates

None

Hazard Potential

Low

Foundations

Soil

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.