Happy Hollow Lake 2 Dam
Happy Hollow Lake 2 Dam is an earth dam located in Knox County, Illinois, built in 1965. It carries a Significant hazard potential classification.
About Happy Hollow Lake 2 Dam
The primary purpose of Happy Hollow Lake 2 Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Happy Hollow Lake Association (private). It impounds the Trib Spoon River near Dahinda.
The dam stands 34 feet tall and stretches 240 feet across, and has a maximum storage capacity of 77 acre-feet. 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. The most recent inspection on record was 03/28/2024.
At 34 feet, this dam is taller than 80% of dams nationwide.
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Location
| State | Illinois |
| County | Knox |
| Nearest City | Dahinda |
| River/Stream | Trib Spoon River |
| Coordinates | 40.92637, -90.06978 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 34 ft |
| Dam Height | 34 ft |
| Dam Length | 240 ft |
| Year Completed | 1965 (61 years old) |
Storage & Hydraulics
| NID Storage | 77 acre-ft |
| Max Storage | 77 acre-ft |
| Normal Storage | 15 acre-ft |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | HAPPY HOLLOW LAKE ASSOCIATION |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Not Available |
| Last Inspection | 03/28/2024 |
| Emergency Action Plan | No |
Identifiers
| NID ID | IL01160 |
| Federal ID | IL01160 |
| More Info | State Dam Safety Program |