John C. Hill Lake Dam Reservoir Report

Last Updated: December 8, 2025

John C.


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Summary

Hill Lake Dam, located in Gasconade, Missouri, is a privately owned earth dam built in 2005 by Lewis-Bade, Inc. It stands at a height of 52 feet with a hydraulic height of 46 feet, serving the purpose of storing water from Little Berger Creek. With a storage capacity of 523 acre-feet and a surface area of 23 acres, the dam plays a crucial role in managing water resources in the region.

This dam has a high hazard potential and is regularly inspected by the DAM AND RESERVOIR SAFETY PROG to ensure its structural integrity. Despite its satisfactory condition assessment in 2007, the dam's emergency action plan was last revised in 2014, raising concerns about its readiness for potential emergencies. The surrounding area, including the city of Hermann, relies on the dam for water supply and flood control, highlighting its importance in managing water resources and mitigating climate-related risks.

With a drainage area of 178 square miles and a maximum discharge of 191 cubic feet per second, John C. Hill Lake Dam plays a vital role in regulating water flow and preventing downstream flooding. As the primary dam type being earth with a buttress core, this structure showcases the importance of sustainable water resource management practices in addressing climate change impacts. Its location, design, and operational features make it a focal point for water resource and climate enthusiasts seeking to understand the critical role of dams in ensuring water security and resilience in the face of changing environmental conditions.

Year Completed

2005

Dam Length

885

Dam Height

52

River Or Stream

LITTLE BERGER CREEK

Surface Area

23

Hydraulic Height

46

Drainage Area

178

Nid Storage

523

Structural Height

52

Outlet Gates

Uncontrolled

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

52
       
Seasonal Comparison

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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.