W. Assmessen Reservoir Report
Nearby: V. Garrett Lowell West Dam
Last Updated: December 7, 2025
W.
°F
°F
mph
Wind
%
Humidity
Summary
Assmessen is a private dam located in Sully, South Dakota, with a primary purpose that is not specified in the data. Completed in 1947, this earth dam stands at a height of 16 feet and has a length of 720 feet. The dam has a storage capacity of 115 acre-feet, with a normal storage level of 62 acre-feet. It is regulated by the South Dakota Department of Environment and Natural Resources (DENR) and is subject to state permitting, inspection, and enforcement.
Despite being classified as a low hazard potential structure, W. Assmessen has not been rated for its condition assessment. The dam is situated on the TR MISSO river or stream and is under the jurisdiction of the St. Paul District of the US Army Corps of Engineers. With a maximum discharge capacity of 1875 cubic feet per second, the dam provides flood protection and water management benefits to the surrounding area. The dam does not have associated structures or outlet gates, and its emergency action plan (EAP) status and risk assessment information are not provided in the data.
Water resource and climate enthusiasts interested in the infrastructure and management of W. Assmessen can appreciate its historical significance and the role it plays in water resource management in South Dakota. The dam's location, design, and regulatory oversight offer valuable insights into the management of water resources in the region. Further exploration of the dam's condition assessment, emergency preparedness, and risk management measures could provide additional context for understanding its role in the local ecosystem and community resilience efforts.
Year Completed |
1947 |
Dam Length |
720 |
Dam Height |
16 |
River Or Stream |
TR MISSONot RatedI |
Primary Dam Type |
Earth |
Hydraulic Height |
16 |
Nid Storage |
115 |
Hazard Potential |
Low |
Nid Height |
16 |
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.
W. Assmessen