Ambnot Rated Bros No.1 Reservoir Report
Last Updated: December 8, 2025
Ambnot Rated Bros No.1 is a privately owned dam located in Mellette, South Dakota, along the TR Little White Offstream river.
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Summary
Completed in 1953, this Earth-type dam stands at a height of 34 feet and has a length of 694 feet, providing a maximum storage capacity of 136 acre-feet. Despite its age, the dam is state-regulated and undergoes regular inspections, with a low hazard potential and a condition assessment that is currently not rated.
Managed by the DENR and falling under the jurisdiction of South Dakota, Ambnot Rated Bros No.1 plays a crucial role in water resource management in the region. Its primary purpose and specific purposes are not specified, but it serves as a key infrastructure for regulating water flow and storage. The dam's location and design ensure that it meets state permitting and enforcement requirements, contributing to the overall water resource management efforts in the area.
With a designated emergency action plan (EAP) status that is not rated and no recent risk assessments or management measures documented, Ambnot Rated Bros No.1 stands as a testament to the importance of maintaining and monitoring critical infrastructure for water resources. As climate change continues to impact water availability and quality, ensuring the safety and functionality of dams like Ambnot Rated Bros No.1 becomes increasingly vital for sustainable water management in South Dakota.
Year Completed |
1953 |
Dam Length |
694 |
Dam Height |
34 |
River Or Stream |
TR LITTLE WHITE OFFSTREAM |
Primary Dam Type |
Earth |
Hydraulic Height |
34 |
Nid Storage |
136 |
Hazard Potential |
Low |
Nid Height |
34 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
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.
Ambnot Rated Bros No.1