Upper Big Blue River Structure No. 3
Upper Big Blue River Structure No. 3 is an earth dam located in Rush County, Indiana, built in 1974. It carries a Significant hazard potential classification and has a fair condition assessment.
About Upper Big Blue River Structure No. 3
The primary purpose of Upper Big Blue River Structure No. 3 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 Big Blue River Conservancy District (local government). It impounds the Threemile Creek near Carthage.
The dam stands 54 feet tall and stretches 840 feet across, creates a reservoir covering 44 acres, has a maximum storage capacity of 3,840 acre-feet, and collects water from a drainage area of 11 square miles. 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. Its condition is rated fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. The most recent inspection on record was 04/18/2019.
At 54 feet, this dam is taller than 94% of dams nationwide.
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Location
| State | Indiana |
| County | Rush |
| Nearest City | Carthage |
| River/Stream | Threemile Creek |
| Coordinates | 39.76150, -85.54355 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 54 ft |
| Dam Height | 54 ft |
| Dam Length | 840 ft |
| Year Completed | 1974 (52 years old) |
Storage & Hydraulics
| NID Storage | 3,840 acre-ft |
| Max Storage | 3,840 acre-ft |
| Normal Storage | 355 acre-ft |
| Surface Area | 44 acres |
| Drainage Area | 11 sq mi |
| Max Discharge | 12,337 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | BIG BLUE RIVER CONSERVANCY DISTRICT |
| Owner Type | Local Government |
| Hazard Classification | Significant |
| Condition Assessment | Fair |
| Last Inspection | 04/18/2019 |
| Emergency Action Plan | No |
Identifiers
| NID ID | IN00231 |
| Federal ID | IN00231 |
| More Info | State Dam Safety Program |