Rowden Lake Dam
Rowden Lake Dam is an earth dam located in Jersey County, Illinois, built in 1971. It carries a Low hazard potential classification.
About Rowden Lake Dam
The primary purpose of Rowden Lake Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Frank Rowen (private). It impounds the Piasa Creek-offstream near Alton.
The dam stands 40 feet tall and stretches 380 feet across, and has a maximum storage capacity of 160 acre-feet. Completed in 1971, the structure is well into its service life at over 50 years old.
This dam has a low hazard potential classification, meaning that failure would cause minimal damage, limited primarily to the dam owner's property, with no expected loss of life. The most recent inspection on record was 08/27/2025.
At 40 feet, this dam is taller than 87% of dams nationwide.
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Location
| State | Illinois |
| County | Jersey |
| Nearest City | Alton |
| River/Stream | Piasa Creek-offstream |
| Coordinates | 39.10294, -90.14902 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 40 ft |
| Dam Height | 40 ft |
| Dam Length | 380 ft |
| Year Completed | 1971 (55 years old) |
Storage & Hydraulics
| NID Storage | 160 acre-ft |
| Max Storage | 160 acre-ft |
| Normal Storage | 121 acre-ft |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | FRANK ROWEN |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Not Available |
| Last Inspection | 08/27/2025 |
| Emergency Action Plan | No |
Identifiers
| NID ID | IL00900 |
| Federal ID | IL00900 |
| More Info | State Dam Safety Program |