Big Bend Dam Reservoir Report

Last Updated: December 13, 2025

Big Bend Dam, also known as Lake Sharpe, is a federal-owned structure located in Chamberlain, South Dakota, along the Missouri River.


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Summary

Completed in 1963, the dam serves multiple purposes including flood risk reduction, hydroelectric power generation, irrigation, navigation, and recreation. With a structural height of 95 feet and a hydraulic height of 78 feet, the dam has a storage capacity of 1.9 million acre-feet and a surface area of 60,000 acres.

Despite its reliable flood risk reduction capabilities, Big Bend Dam faces a high hazard potential due to the risk of overtopping during extreme flood events. The US Army Corps of Engineers (USACE) has implemented ongoing risk management measures, including regular monitoring, maintenance, and repairs, as well as working with state and local agencies to improve emergency preparedness and public awareness of flood risks. Following significant flooding in 2011, additional measures such as enhanced foundation monitoring, upgrades to drainage systems, and repairs to the spillway have been completed to mitigate potential risks.

Communities downstream of Big Bend Dam are advised to stay informed about flood forecasts, evacuation plans, and emergency actions to reduce individual risks. USACE continues to evaluate ways to further reduce risks associated with the dam and encourages public engagement in water management in the Missouri River basin. For more information on the USACE Dam Safety Program and risk assessments, visit: https://www.usace.army.mil/Missions/Civil-Works/Dam-Safety-Program.

Year Completed

1963

Dam Length

10570

River Or Stream

MISSOURI RIVER

Primary Dam Type

Earth

Surface Area

60000

Hydraulic Height

78

Drainage Area

5840

Nid Storage

1900000

Structural Height

95

Outlet Gates

Vertical Lift - 0

Hazard Potential

High

Foundations

Rock, Soil

Nid Height

95
       
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.