Lake Osage Dam Reservoir Report

Last Updated: December 19, 2025

Lake Osage Dam, also known as Camp Arrowhead Dam, is a privately-owned structure located in Webster, Missouri, along the Osage Fork of the Gasconade River.


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Summary

Built in 1959, this Earth-type dam stands at a height of 38 feet and spans 600 feet in length, with a maximum storage capacity of 151 acre-feet and a normal storage of 108 acre-feet. The primary purpose of Lake Osage Dam is for recreation, offering a surface area of 12 acres for outdoor activities.

Managed by the DAM AND RESERVOIR SAFETY PROG, the state-regulated dam is subject to regular inspections and enforcement to ensure its safety and satisfactory condition. With a hazard potential rated as high, the dam poses moderate risk and is categorized as having a moderate risk management level. Despite its risk level, the dam has been deemed to meet guidelines for emergency action plans, although specifics on inundation maps and risk assessment summaries are not provided. Overall, Lake Osage Dam serves as a vital resource for water recreation enthusiasts in the area while also being subject to necessary regulatory oversight to ensure public safety.

Year Completed

1959

Dam Length

600

Dam Height

38

River Or Stream

TR OSAGE FK-GASCONADE RIVER

Primary Dam Type

Earth

Surface Area

12

Drainage Area

346

Nid Storage

151

Structural Height

38

Outlet Gates

Uncontrolled

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

38
       
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.