Opal Dam Reservoir Report
Nearby: C. Vansickel R. Talley No.2
Last Updated: December 12, 2025
Opal Dam in South Dakota, completed in 1937, stands as a crucial water resource structure along the TR Cheyenne river.
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Summary
This state-regulated earth dam, with a height of 22 feet and a storage capacity of 558 acre-feet, plays a vital role in managing water resources in the region. The dam's uncontrolled spillway, with a width of 70 feet, ensures the safe release of excess water during periods of high flow.
Despite its fair condition assessment in 2018, Opal Dam is classified as having a high hazard potential, highlighting the importance of regular inspections and maintenance. The dam's moderate risk assessment underscores the need for ongoing risk management measures to mitigate potential hazards. With its location in Meade County and ownership by the state, Opal Dam serves as a key infrastructure for water supply, flood control, and environmental conservation in the region, making it a landmark for water resource and climate enthusiasts to study and appreciate.
Year Completed |
1937 |
Dam Length |
515 |
Dam Height |
22 |
River Or Stream |
TR CHEYENNE |
Primary Dam Type |
Earth |
Hydraulic Height |
22 |
Drainage Area |
7 |
Nid Storage |
558 |
Outlet Gates |
None |
Hazard Potential |
High |
Foundations |
Soil |
Nid Height |
22 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Moreau R Near Faith Sd
|
14cfs |
Cheyenne R Near Plainview Sd
|
0cfs |
Belle Fourche River Near Elm Springs
|
17900cfs |
Belle Fourche R Near Sturgis Sd
|
34cfs |
Elk Cr Near Elm Springs Sd
|
0cfs |
Horse Cr Above Vale Sd
|
13cfs |
Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
Opal Dam