Williams No.1 Reservoir Report
Nearby: Bryan No. 1 Edwards Cattle Co. #1
Last Updated: December 13, 2025
Williams No.1 is a privately owned dam located in Mellette, South Dakota, along the tributary of Little White River.
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Summary
Constructed in 1967, this earth dam stands at 25 feet high and spans 325 feet in length, with a storage capacity of 26 acre-feet. While the primary purpose of Williams No.1 is not specified, it is regulated by the South Dakota Department of Environment and Natural Resources (DENR) and is subject to state permitting, inspection, and enforcement.
With a low hazard potential and a current condition assessment of "Not Rated," Williams No.1 serves as a key infrastructure for water resource management in the region. While specific details on the dam's associated structures, inspection frequency, and emergency action plan are not provided, its location within the St. Paul District of the US Army Corps of Engineers signifies a level of oversight and regulation. The dam's presence contributes to the overall water management efforts in the area, ensuring efficient water storage and discharge capabilities for the surrounding community.
As a significant component of the water infrastructure in South Dakota, Williams No.1 plays a crucial role in mitigating flood risks and providing essential water storage for the region. While further details on its operational aspects and risk management measures are not specified in the data, its existence as a state-regulated dam underscores the importance of proper maintenance and oversight to ensure its continued functionality and safety. For water resource and climate enthusiasts, Williams No.1 represents a piece of the broader puzzle in sustainable water management and climate resilience efforts in the region.
Year Completed |
1967 |
Dam Length |
325 |
Dam Height |
25 |
River Or Stream |
TRIB. LITTLE WHITE RIVER |
Primary Dam Type |
Earth |
Hydraulic Height |
25 |
Nid Storage |
26 |
Hazard Potential |
Low |
Nid Height |
25 |
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.
Williams No.1