Sinnwell Dam Reservoir Report
Nearby: Burhans Dam Jorgensen Dam
Last Updated: December 10, 2025
Located in Madison County, Iowa, Sinnwell Dam is a privately owned structure designed by the Soil Conservation Service (SCS) with a primary purpose of fire protection, stock, or small fish pond.
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Summary
Completed in 1987, this earth dam stands at a height of 27 feet and spans 365 feet in length, with a storage capacity of 20 acre-feet. The dam is situated on the TR- Middle River and is regulated by the Iowa Department of Natural Resources, with state permitting, inspection, and enforcement in place to ensure its safety and compliance.
With a low hazard potential and a moderate risk assessment, Sinnwell Dam plays a crucial role in water resource management in the region. The dam's normal storage of 8 acre-feet and surface area of 1.4 acres provide valuable water resources for various purposes, while also serving as a protective barrier against potential flooding events. Despite its uncontrolled spillway type, Sinnwell Dam continues to be a vital asset for fire protection and stock water supply, highlighting its importance in both water resource management and climate resilience efforts in the area.
Year Completed |
1987 |
Dam Length |
365 |
Dam Height |
27 |
River Or Stream |
TR- MIDDLE RIVER |
Primary Dam Type |
Earth |
Surface Area |
1.4 |
Drainage Area |
0.1 |
Nid Storage |
20 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
27 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Raccoon River At Van Meter
|
1640cfs |
North River Near Norwalk
|
48cfs |
Raccoon River Near West Des Moines
|
1300cfs |
Middle River Near Indianola
|
48cfs |
Raccoon River At 63rd Street At Des Moines
|
587cfs |
Walnut Creek At Des Moines
|
10cfs |
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.
Sinnwell Dam