Harmon Pond Dam is an earth dam located in Bureau County, Illinois, built in 1974. It carries a Significant hazard potential classification.
Dam profile
NID height · 37 ft37 ft tall and 1,126 ft long, taller than 83% 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 Harmon Pond Dam
The primary purpose of Harmon Pond Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Walter Harmon (private). It impounds the Trib Rocky Run near Tiskilwa.
The dam stands 37 feet tall and stretches 1,126 feet across, and has a maximum storage capacity of 51 acre-feet. Completed in 1974, 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 05/06/2025.
At 37 feet, this dam is taller than 83% of dams nationwide.
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Location
| State | Illinois |
| County | Bureau |
| Nearest City | Tiskilwa |
| River/Stream | Trib Rocky Run |
| Coordinates | 41.27377, -89.57835 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 37 ft |
| Dam Height | 37 ft |
| Dam Length | 1,126 ft |
| Year Completed | 1974 (52 years old) |
Storage & Hydraulics
| NID Storage | 51 acre-ft |
| Max Storage | 51 acre-ft |
| Normal Storage | 37 acre-ft |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Walter Harmon |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Not assessed |
| Last Inspection | 05/06/2025 |
| Emergency Action Plan | No |
Identifiers
| NID ID | IL01129 |
| Federal ID | IL01129 |
| More Info | State Dam Safety Program |