Porter Moss Agate Dam Reservoir Report
Nearby: Tubbs Moss Agate Dam Frosh (Nid)
Last Updated: December 6, 2025
Porter Moss Agate Dam, located in Fall River, South Dakota, serves as a crucial water resource structure regulating a tributary of the Cheyenne River.
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Summary
Built in 1940, this earth dam stands at 18 feet in height and spans 550 feet in length, with a storage capacity of 144 acre-feet. Despite its low hazard potential, the dam remains state-regulated and regularly inspected by the South Dakota Department of Environment and Natural Resources to ensure its structural integrity and safety.
The dam's primary purpose and associated structures are unspecified, reflecting its private ownership and limited federal involvement. However, its location within the Omaha District and its designation as a state-regulated dam highlight its importance in water resource management. Although its condition assessment is currently "Not Rated," Porter Moss Agate Dam's historical significance and strategic position within the local watershed make it a focal point for water resource and climate enthusiasts interested in sustainable water management practices.
With Dusty Johnson (R) representing the area in Congress, issues related to water infrastructure and climate resilience are likely to be on the agenda, positioning Porter Moss Agate Dam as a key asset in the region's water resource strategy. As the dam's risk assessment and emergency preparedness measures continue to evolve, stakeholders and enthusiasts alike can monitor its progress in safeguarding the surrounding communities and ecosystem from potential water-related hazards.
Year Completed |
1940 |
Dam Length |
550 |
Dam Height |
18 |
River Or Stream |
TRIBUTARY OF CHEYENNE RIVER |
Primary Dam Type |
Earth |
Hydraulic Height |
18 |
Nid Storage |
144 |
Hazard Potential |
Low |
Nid Height |
18 |
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.
Porter Moss Agate Dam