Highway Dept. #3
Highway Dept. #3 is an earth dam located in Mellette County, South Dakota, built in 1970. It carries a Significant hazard potential classification.
About Highway Dept. #3
Highway Dept. #3 is a dam in Mellette, South Dakota. The dam is owned by Dept. Of Transportation (state). It impounds the Tr Little White Offstream.
The dam stands 91 feet tall and stretches 650 feet across, and has a maximum storage capacity of 146 acre-feet. Completed in 1970, 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 11/02/2023.
At 91 feet, this dam is taller than 98% of all dams in the United States.
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Location
| State | South Dakota |
| County | Mellette |
| Nearest City | None |
| River/Stream | Tr Little White Offstream |
| Coordinates | 43.54849, -100.74410 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 91 ft |
| Dam Height | 91 ft |
| Dam Length | 650 ft |
| Year Completed | 1970 (56 years old) |
Storage & Hydraulics
| NID Storage | 146 acre-ft |
| Max Storage | 146 acre-ft |
| Normal Storage | 107 acre-ft |
| Max Discharge | 40 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Other |
| Owner | DEPT. OF TRANSPORTATION |
| Owner Type | State |
| Hazard Classification | Significant |
| Last Inspection | 11/02/2023 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | SD01471 |
| Federal ID | SD01471 |
| More Info | State Dam Safety Program |