Fort Randall Dam Reservoir Report

Last Updated: December 13, 2025

Fort Randall Dam, also known as Lake Francis Case, is a crucial structure located on the Missouri River in South Dakota, designed by the US Army Corps of Engineers to primarily manage flood risk.


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Summary

Completed in 1954, this Earth-type dam stands at a structural height of 170 feet and spans a length of 10,700 feet, with a storage capacity of 6.3 million acre-feet. Despite its ability to reduce floods, the dam still poses a high hazard potential due to the risk of erosion, spillway damage, and potential overtopping during extreme flood events.

The USACE Dam Safety Program continuously monitors and assesses the dam's condition to mitigate risks and ensure public safety. Following flooding in 2011, additional instrumentation was installed for enhanced foundation monitoring, and repairs were made to strengthen the spillway's resilience. Communities downstream are advised to stay informed about flood forecasts, evacuation plans, and individual preparedness measures to minimize risks associated with dam failure and potential downstream flooding. For more information on the USACE Dam Safety Program and risk assessments, visit their website at https://www.usace.army.mil/Missions/Civil-Works/Dam-Safety-Program.

Year Completed

1954

Dam Length

10700

River Or Stream

MISSOURI RIVER

Primary Dam Type

Earth

Surface Area

118400

Hydraulic Height

160

Drainage Area

14150

Nid Storage

6300000

Structural Height

170

Outlet Gates

Vertical Lift - 0

Hazard Potential

High

Foundations

Rock, Soil

Nid Height

170
       
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.