Van Collons No.1 Reservoir Report
Nearby: Derry Robert No.1 Ryno #2
Last Updated: December 13, 2025
Van Collons No.1 is a privately owned dam located in Mellette, South Dakota, along the White Thunder Creek tributary.
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Summary
Built in 1964, this earthen dam stands at 25 feet tall and stretches 347 feet in length, with a storage capacity of 17 acre-feet. The dam is regulated by the South Dakota Department of Environment and Natural Resources (DENR) and is subject to state permitting, inspection, and enforcement requirements. Despite its age, the dam is rated as having a low hazard potential and is currently in a condition that has not been formally assessed.
Managed by a private owner, Van Collons No.1 serves primarily as a flood control structure, with a maximum discharge capacity of 152 cubic feet per second. The dam's emergency action plan (EAP) status, risk assessment, and management measures are currently unspecified. The surrounding area seems to have a low risk of inundation, and the dam does not fall under the jurisdiction of the US Army Corps of Engineers. Overall, Van Collons No.1 presents an interesting case study for water resource and climate enthusiasts, showcasing the importance of regular inspection and maintenance of aging infrastructure in safeguarding communities from potential hazards.
Year Completed |
1964 |
Dam Length |
347 |
Dam Height |
25 |
River Or Stream |
TRIB-WHITE THUNDER CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
25 |
Nid Storage |
17 |
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.
Van Collons No.1