Lake Thunderhawk Dam is an earth dam located in Johnson County, Illinois, built in 1975. It carries a Low hazard potential classification.
Dam profile
NID height · 31 ft31 ft tall and 490 ft long, taller than 72% of U.S. dams with a recorded height. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic embankment section and the water level is illustrative.
About Lake Thunderhawk Dam
The primary purpose of Lake Thunderhawk Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Frnak Nutty (private). It impounds the Little Saline River near Mitchellsville.
The dam stands 31 feet tall and stretches 490 feet across, and has a maximum storage capacity of 383 acre-feet. Completed in 1975, 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 07/26/2024.
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Location
| State | Illinois |
| County | Johnson |
| Nearest City | Mitchellsville |
| River/Stream | Little Saline River |
| Coordinates | 37.56162, -88.75541 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 31 ft |
| Dam Height | 31 ft |
| Dam Length | 490 ft |
| Year Completed | 1975 (51 years old) |
Storage & Hydraulics
| NID Storage | 383 acre-ft |
| Max Storage | 383 acre-ft |
| Normal Storage | 232 acre-ft |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Frnak Nutty |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Last Inspection | 07/26/2024 |
| Emergency Action Plan | No |
Identifiers
| NID ID | IL00957 |
| Federal ID | IL00957 |
| More Info | State Dam Safety Program |