Gilbert No.1 Reservoir Report
Nearby: Salmen No.1 Hett No.1
Last Updated: December 6, 2025
Gilbert No.1 is a privately owned earth dam located in Harding, South Dakota, along the TR-South Fork Grand River.
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Summary
Built in 1954 by the Natural Resources Conservation Service, this dam stands at a height of 19 feet and has a length of 1300 feet, providing a storage capacity of 285 acre-feet. The dam's primary purpose and design are not specified, but it is regulated by the South Dakota Department of Environment and Natural Resources, with state permitting, inspection, and enforcement in place.
Despite its low hazard potential and current "Not Rated" condition assessment, Gilbert No.1 has not undergone recent inspections or assessments. Emergency preparedness measures such as an Emergency Action Plan (EAP) and inundation maps are not reported to be in place. The dam is not owned or funded by federal agencies, and there is no information available on associated structures or operational details. With a maximum discharge capacity of 8400 cubic feet per second, Gilbert No.1 plays a crucial role in managing water resources in the region, highlighting the importance of regular monitoring and maintenance to ensure public safety and environmental protection.
Year Completed |
1954 |
Dam Length |
1300 |
Dam Height |
19 |
River Or Stream |
TR-SOUTH FORK GRAND RIVER |
Primary Dam Type |
Earth |
Hydraulic Height |
19 |
Nid Storage |
285 |
Hazard Potential |
Low |
Nid Height |
19 |
Seasonal Comparison
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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.
Gilbert No.1