Mill Creek Structure 8 Dam is an earth dam located in Clark County, Illinois, built in 1987. It carries a Low hazard potential classification.
Dam profile
NID height · 40 ft40 ft tall and 650 ft long, taller than 86% 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 Mill Creek Structure 8 Dam
The primary purpose of Mill Creek Structure 8 Dam is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by Mill Creek Conservancy District (private). It impounds the Blackburn Branch near Snyder.
The dam stands 40 feet tall and stretches 650 feet across, has a maximum storage capacity of 3,219 acre-feet, and collects water from a drainage area of 6 square miles. Completed in 1987, the structure is 39 years old.
This dam has a low hazard potential classification, meaning that failure would cause minimal damage, limited primarily to the dam owner's property, with no expected loss of life. An emergency action plan is in place for this dam. The most recent inspection on record was 09/13/2022.
At 40 feet, this dam is taller than 86% of dams nationwide.
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Location
| State | Illinois |
| County | Clark |
| Nearest City | Snyder |
| River/Stream | Blackburn Branch |
| Coordinates | 39.30931, -87.74933 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 40 ft |
| Dam Height | 40 ft |
| Dam Length | 650 ft |
| Year Completed | 1987 (39 years old) |
Storage & Hydraulics
| NID Storage | 3,219 acre-ft |
| Max Storage | 3,219 acre-ft |
| Normal Storage | 228 acre-ft |
| Drainage Area | 6 sq mi |
| Max Discharge | 6,528 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | Mill Creek Conservancy District |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Last Inspection | 09/13/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | IL50040 |
| Federal ID | IL50040 |
| More Info | State Dam Safety Program |