Thunderbird Lake Dam
Thunderbird Lake Dam is an earth dam located in Jersey County, Illinois, built in 1965. It carries a Low hazard potential classification.
About Thunderbird Lake Dam
The primary purpose of Thunderbird Lake Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Unknown;unknown (private). It impounds the Tr- Little Piasa Creek near Alton On Mississippi.
The dam stands 28 feet tall and stretches 300 feet across, creates a reservoir covering 4 acres, has a maximum storage capacity of 48 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1965, 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 06/23/2025.
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Location
| State | Illinois |
| County | Jersey |
| Nearest City | Alton On Mississippi |
| River/Stream | Tr- Little Piasa Creek |
| Coordinates | 39.03885, -90.16686 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 28 ft |
| Dam Height | 28 ft |
| Dam Length | 300 ft |
| Year Completed | 1965 (61 years old) |
Storage & Hydraulics
| NID Storage | 48 acre-ft |
| Max Storage | 48 acre-ft |
| Normal Storage | 32 acre-ft |
| Surface Area | 4 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 194 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | UNKNOWN;UNKNOWN |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Not Available |
| Last Inspection | 06/23/2025 |
| Emergency Action Plan | No |
Identifiers
| NID ID | IL40044 |
| Federal ID | IL40044 |
| More Info | State Dam Safety Program |