Ilex Dam
Ilex Dam is an earth dam located in Polk County, Iowa, built in 1980. It carries a Significant hazard potential classification.
About Ilex Dam
The primary purpose of Ilex Dam is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by Polk County Public Works Dept (local government). It impounds the Trib To Des Moines River near Des Moines.
The dam stands 10 feet tall and stretches 500 feet across, has a maximum storage capacity of 64 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1980, the structure is 46 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. The most recent inspection on record was 10/30/2024.
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Location
| State | Iowa |
| County | Polk |
| Nearest City | Des Moines |
| River/Stream | Trib To Des Moines River |
| Coordinates | 41.64810, -93.60910 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 10 ft |
| Dam Height | 10 ft |
| Dam Length | 500 ft |
| Year Completed | 1980 (46 years old) |
Storage & Hydraulics
| NID Storage | 64 acre-ft |
| Max Storage | 64 acre-ft |
| Drainage Area | 1 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | Polk County Public Works Dept |
| Owner Type | Local Government |
| Hazard Classification | Significant |
| Condition Assessment | Not Rated |
| Last Inspection | 10/30/2024 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | IA04375 |
| Federal ID | IA04375 |
| More Info | State Dam Safety Program |