Maffitt Reservoir Dam
Maffitt Reservoir Dam is an earth dam located in Dallas County, Iowa, built in 1944. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Maffitt Reservoir Dam
The primary purpose of Maffitt Reservoir Dam is water supply. The dam stores water for municipal, industrial, or agricultural use, helping ensure a reliable supply for the surrounding area. The dam is owned by Des Moines Water Works (public utility). It impounds the Tr-raccoon River near West Des Moines.
The dam stands 79 feet tall and stretches 1,800 feet across, creates a reservoir covering 230 acres, has a maximum storage capacity of 6,700 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1944, the structure is well-established, with more than 75 years of service.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. Notably, no emergency action plan is currently on file for this high-hazard dam. The most recent inspection on record was 05/31/2023.
At 79 feet, this dam is taller than 97% of all dams in the United States.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Iowa dam safety program can provide more specific information about emergency planning for this structure.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Iowa |
| County | Dallas |
| Nearest City | West Des Moines |
| River/Stream | Tr-raccoon River |
| Coordinates | 41.51720, -93.79210 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 79 ft |
| Dam Height | 79 ft |
| Dam Length | 1,800 ft |
| Year Completed | 1944 (82 years old) |
Storage & Hydraulics
| NID Storage | 6,700 acre-ft |
| Max Storage | 6,700 acre-ft |
| Normal Storage | 5,200 acre-ft |
| Surface Area | 230 acres |
| Drainage Area | 1 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Des Moines Water Works |
| Owner Type | Public Utility |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 05/31/2023 |
| Emergency Action Plan | No |
Identifiers
| NID ID | IA01338 |
| Federal ID | IA01338 |
| More Info | State Dam Safety Program |