Bnot Ratedke Reservoir Report
Nearby: Oakley Eide No.1 Steffen Dam
Last Updated: December 13, 2025
Bnot Ratedke is a state-regulated dam located in Gregory, South Dakota, along Coon Creek.
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Summary
Built in 1936 by the Works Progress Administration (WPA), this earth dam stands at a height of 25 feet and has a length of 480 feet. With a storage capacity of 484 acre-feet, it serves the primary purpose of flood control in the area. The dam has a low hazard potential and a moderate risk assessment rating of 3.
Despite its age, Bnot Ratedke is regularly inspected, with the last inspection taking place in May 2017. The dam is equipped with an uncontrolled spillway that is 30 feet wide, allowing for a maximum discharge rate of 2095 cubic feet per second. While the condition assessment is listed as "Not Rated," the dam is considered to be in moderate risk, prompting the need for ongoing risk management measures to ensure its safety and reliability. With its historical significance and vital role in water resource management, Bnot Ratedke is a key structure in the region's infrastructure.
Year Completed |
1936 |
Dam Length |
480 |
Dam Height |
25 |
River Or Stream |
COON CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
25 |
Drainage Area |
2 |
Nid Storage |
484 |
Outlet Gates |
None |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
25 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Platte Creek Near Platte
|
3cfs |
Niobrara River At Mariaville
|
1650cfs |
Keya Paha R At Wewela Sd
|
54cfs |
Long Pine Creek Near Riverview
|
191cfs |
White R Near Oacoma Sd
|
105cfs |
Keya Paha R Near Keyapaha Sd
|
33cfs |
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.
Bnot Ratedke