A.W. Spiry Reservoir Report
Last Updated: December 13, 2025
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Summary
Spiry is a privately owned earth dam located in Walworth, South Dakota, with a height of 25 feet and a length of 380 feet. Completed in 1956, this dam has a normal storage capacity of 35 acre-feet and a maximum storage capacity of 70 acre-feet. It is regulated by the South Dakota Department of Environment and Natural Resources (DENR) and is rated as having a low hazard potential.
The dam's primary purpose and associated structures are not specified in the data, but it is noted that the dam has a maximum discharge of 600 cubic feet per second. Despite being in operation for several decades, the condition assessment of A.W. Spiry is listed as "Not Rated," indicating a lack of recent evaluation. The dam does not have an Emergency Action Plan (EAP) in place, and there is no information regarding risk assessment or management measures.
Given its location in South Dakota and its modest size and capacity, A.W. Spiry may not be a high-profile structure in the realm of water resource management and climate adaptation. However, its presence and regulatory status highlight the importance of monitoring and maintaining even smaller dams to ensure public safety and environmental integrity in the face of changing climate conditions.
Year Completed |
1956 |
Dam Length |
380 |
Dam Height |
25 |
River Or Stream |
TR-MISSONot RatedI |
Primary Dam Type |
Earth |
Hydraulic Height |
25 |
Nid Storage |
70 |
Hazard Potential |
Low |
Nid Height |
25 |
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 |
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