Maffitt Reservoir Dam Reservoir Report
Last Updated: December 13, 2025
Maffitt Reservoir Dam, located in Dallas County, Iowa, is a crucial infrastructure owned by a public utility and regulated by the Iowa Department of Natural Resources.
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Summary
Completed in 1944, this earth dam stands at a height of 79 feet and spans 1800 feet along the Raccoon River. Its primary purpose is to provide water supply, with a storage capacity of 6700 acre-feet and a normal storage level of 5200 acre-feet.
With a surface area of 230 acres and a drainage area of 1.41 square miles, Maffitt Reservoir Dam poses a high hazard potential but has been assessed as satisfactory in condition. The dam features an uncontrolled spillway with a width of 8 feet, and it is inspected every two years for safety and maintenance. Despite its age, the dam remains a critical component of the water infrastructure in the West Des Moines area, ensuring a reliable water supply for the local community while managing flood risk along the Raccoon River.
Year Completed |
1944 |
Dam Length |
1800 |
Dam Height |
79 |
River Or Stream |
TR-RACCOON RIVER |
Primary Dam Type |
Earth |
Surface Area |
230 |
Drainage Area |
1.41 |
Nid Storage |
6700 |
Hazard Potential |
High |
Foundations |
Soil |
Nid Height |
79 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Raccoon River Near West Des Moines
|
1300cfs |
Raccoon River At 63rd Street At Des Moines
|
587cfs |
Walnut Creek At Des Moines
|
10cfs |
North River Near Norwalk
|
48cfs |
Raccoon River At Van Meter
|
1640cfs |
Raccoon River At Fleur Drive
|
1200cfs |
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.
Maffitt Reservoir Dam
Walnut Woods Drive West Des Moines