A.W. Spiry Reservoir Report
Last Updated: December 13, 2025
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Summary
Spiry, located in Walworth, South Dakota, is a privately owned earth dam completed in 1953 with a height of 26 feet and a length of 400 feet. The dam has a storage capacity of 55 acre-feet, with a normal storage level of 30 acre-feet. It is regulated by the South Dakota Department of Environment and Natural Resources (DENR) and is regularly inspected, permitted, and enforced to ensure its safety and compliance with state regulations.
The dam, situated on the TR-MISSONot RatedI river or stream, has a low hazard potential and is currently assessed as "Not Rated" in terms of its condition. Although the dam does not have any associated structures, it plays a crucial role in water resource management and flood control in the area. The A.W. Spiry dam also has a maximum discharge capacity of 720 cubic feet per second, further highlighting its importance in mitigating potential flooding events and managing water resources effectively.
With a strong foundation and a history of serving its purpose effectively for several decades, A.W. Spiry stands as a significant water resource infrastructure in South Dakota. Its strategic location and design make it a valuable asset for the community, providing essential water storage and flood protection benefits. As climate change continues to impact water resources, the careful monitoring and maintenance of dams like A.W. Spiry will be vital in ensuring the resilience and sustainability of water management systems in the region.
Year Completed |
1953 |
Dam Length |
400 |
Dam Height |
26 |
River Or Stream |
TR-MISSONot RatedI |
Primary Dam Type |
Earth |
Hydraulic Height |
26 |
Nid Storage |
55 |
Hazard Potential |
Low |
Nid Height |
26 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Oak Cr Near Wakpala Sd
|
10cfs |
Grand R At Little Eagle Sd
|
47cfs |
Moreau R Near Whitehorse Sd
|
35cfs |
Beaver Creek Bl Linton
|
39cfs |
Cedar Creek Nr Raleigh
|
20cfs |
Cannonball River Nr Raleigh
|
40cfs |
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.
A.W. Spiry