Marion County Roadgrade Dam 17-76-18
Marion County Roadgrade Dam 17-76-18 is an earth dam located in Marion County, Iowa, built in 1965. It carries a Significant hazard potential classification and has a poor condition assessment.
About Marion County Roadgrade Dam 17-76-18
Marion County Roadgrade Dam 17-76-18 is a dam in Marion, Iowa. The dam is owned by Marion County Board Of Supervisors (local government). It impounds the Tr-des Moines River near Harvey.
The dam stands 40 feet tall and stretches 1,000 feet across, creates a reservoir covering 41 acres, has a maximum storage capacity of 1,144 acre-feet, and collects water from a drainage area of 4 square miles. Completed in 1965, the structure is well into its service life at over 50 years old.
This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. Its condition is rated poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. The most recent inspection on record was 07/02/2024.
At 40 feet, this dam is taller than 87% of dams nationwide.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Iowa |
| County | Marion |
| Nearest City | Harvey |
| River/Stream | Tr-des Moines River |
| Coordinates | 41.38220, -92.96250 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 40 ft |
| Dam Height | 40 ft |
| Dam Length | 1,000 ft |
| Year Completed | 1965 (61 years old) |
Storage & Hydraulics
| NID Storage | 1,144 acre-ft |
| Max Storage | 1,144 acre-ft |
| Normal Storage | 324 acre-ft |
| Surface Area | 41 acres |
| Drainage Area | 4 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Other |
| Owner | Marion County Board of Supervisors |
| Owner Type | Local Government |
| Hazard Classification | Significant |
| Condition Assessment | Poor |
| Last Inspection | 07/02/2024 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | IA00667 |
| Federal ID | IA00667 |
| More Info | State Dam Safety Program |