Sioux Power Plant Dam Reservoir Report

Last Updated: January 12, 2026

The Sioux Power Plant Dam, located in Portage Des Sioux, Missouri, is a significant structure along the T Mississippi River.


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Summary

This public utility-owned dam stands at a height of 102 feet and serves multiple purposes, including flood control and water storage. With a hydraulic height of 107 feet and a storage capacity of 14,039 acre-feet, the dam plays a crucial role in managing the water resources in the region.

Constructed in an impressive buttress design, the Sioux Power Plant Dam has a structural length of 12,000 feet and a spillway width of 10 feet. The dam's uncontrolled spillway and outlet gates contribute to its high hazard potential, although its condition assessment in 2007 deemed it satisfactory. Despite its moderate risk level, the dam is regulated and inspected by the DAM AND RESERVOIR SAFETY PROG, ensuring its continued safe operation and maintenance to mitigate any potential risks to the surrounding area.

The Sioux Power Plant Dam is a vital structure for water management in St. Charles County, Missouri, serving as a key player in the region's flood control and storage efforts. With its strategic location on the T Mississippi River, this dam plays a crucial role in safeguarding the area from potential water-related hazards. As a publicly-owned utility dam, it undergoes regular inspections and enforcement measures to ensure its continued safe operation and protect the community from any risks associated with its high hazard potential.

Dam Length

12000

Dam Height

102

River Or Stream

T MISSISSIPPI

Surface Area

204

Hydraulic Height

107

Drainage Area

204

Nid Storage

14039

Structural Height

102

Outlet Gates

Uncontrolled

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

107
       
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.