New Harrisburg Reservoir Dam is an earth dam located in Saline County, Illinois, built in 1955. It carries a Significant hazard potential classification.
Dam profile
NID height · 38 ft38 ft tall and 1,000 ft long, taller than 84% 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 New Harrisburg Reservoir Dam
New Harrisburg Reservoir Dam is a dam in Saline, Illinois. The dam is owned by City of Harrisburg (local government). It impounds the Trib Middle Fork Saline River near Galatia-offstream.
The dam stands 38 feet tall and stretches 1,000 feet across, creates a reservoir covering 218 acres, has a maximum storage capacity of 6,233 acre-feet, and collects water from a drainage area of 6 square miles. Completed in 1955, 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. An emergency action plan is in place for this dam. The most recent inspection on record was 05/09/2025.
At 38 feet, this dam is taller than 84% of dams nationwide.
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Location
| State | Illinois |
| County | Saline |
| Nearest City | Galatia-offstream |
| River/Stream | Trib Middle Fork Saline River |
| Coordinates | 37.83642, -88.59037 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 38 ft |
| Dam Height | 38 ft |
| Dam Length | 1,000 ft |
| Year Completed | 1955 (71 years old) |
Storage & Hydraulics
| NID Storage | 6,233 acre-ft |
| Max Storage | 6,233 acre-ft |
| Normal Storage | 2,050 acre-ft |
| Surface Area | 218 acres |
| Drainage Area | 6 sq mi |
| Max Discharge | 8,804 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Other |
| Owner | City of Harrisburg |
| Owner Type | Local Government |
| Hazard Classification | Significant |
| Condition Assessment | Not assessed |
| Last Inspection | 05/09/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | IL00017 |
| Federal ID | IL00017 |
| More Info | State Dam Safety Program |