Altamont Reservoir Dam is an earth dam located in Effingham County, Illinois, built in 1972. It carries a Significant hazard potential classification.
Dam profile
NID height · 42 ft42 ft tall and 506 ft long, taller than 88% 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 Altamont Reservoir Dam
The primary purpose of Altamont Reservoir Dam is water supply. The dam stores water for municipal, industrial, or agricultural use, helping ensure a reliable supply for the surrounding area. The dam is owned by City of Altamont (local government). It impounds the Trib Big Creek near Watson.
The dam stands 42 feet tall and stretches 506 feet across, creates a reservoir covering 62 acres, has a maximum storage capacity of 1,255 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1972, 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 05/25/2023.
At 42 feet, this dam is taller than 88% of dams nationwide.
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Location
| State | Illinois |
| County | Effingham |
| Nearest City | Watson |
| River/Stream | Trib Big Creek |
| Coordinates | 39.03219, -88.71443 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 42 ft |
| Dam Height | 42 ft |
| Dam Length | 506 ft |
| Year Completed | 1972 (54 years old) |
Storage & Hydraulics
| NID Storage | 1,255 acre-ft |
| Max Storage | 1,255 acre-ft |
| Normal Storage | 950 acre-ft |
| Surface Area | 62 acres |
| Drainage Area | 1 sq mi |
| Max Discharge | 563 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Water Supply |
| Owner | City of Altamont |
| Owner Type | Local Government |
| Hazard Classification | Significant |
| Condition Assessment | Not assessed |
| Last Inspection | 05/25/2023 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | IL00965 |
| Federal ID | IL00965 |
| More Info | State Dam Safety Program |