Raw Water Reservoir Dam is an earth dam located in Jefferson County, Illinois, built in 1966. It carries a Significant hazard potential classification.
Dam profile
NID height · 20 ft20 ft tall and 1,560 ft long. 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 Raw Water Reservoir Dam
Raw Water Reservoir Dam is a dam in Jefferson, Illinois. The dam is owned by Consolidation Coal Company (private). It impounds the Ward Branch near Plumfield.
The dam stands 20 feet tall and stretches 1,560 feet across, and has a maximum storage capacity of 1,427 acre-feet. Completed in 1966, 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 05/27/2025.
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Location
| State | Illinois |
| County | Jefferson |
| Nearest City | Plumfield |
| River/Stream | Ward Branch |
| Coordinates | 38.15003, -89.02812 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 20 ft |
| Dam Height | 20 ft |
| Dam Length | 1,560 ft |
| Year Completed | 1966 (60 years old) |
Storage & Hydraulics
| NID Storage | 1,427 acre-ft |
| Max Storage | 1,427 acre-ft |
| Normal Storage | 674 acre-ft |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Other |
| Owner | Consolidation Coal Company |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Not assessed |
| Last Inspection | 05/27/2025 |
| Emergency Action Plan | No |
Identifiers
| NID ID | IL00175 |
| Federal ID | IL00175 |
| More Info | State Dam Safety Program |