Chattahoochee Tunnel
- Location
- Cobb County, GA
- Owner
- Cobb County, Georgia Water & Sewer Authority
- Contractor
- Gilbert Southern Corp.
- Value
- $114 million
- Completion
- December 2004
Located in eastern Cobb County, northwest of Atlanta, the $114 million Chattahoochee Tunnel is the largest project the Georgia Water & Sewer Authority of Cobb County has ever undertaken. The joint venture led by Gilbert Southern Corp., a subsidiary of Kiewit Corporation, substantially completed the project in December 2004.
The scope included excavating a 49,600-ft.-long rock tunnel 100- to 350-ft. deep. Approximately 48,300 ft. of 16-ft.-dia. tunnel was excavated using two tunnel boring machines, and 1,300 ft. of 16-ft.-dia. tunnel was excavated by drill-and-blast methods.
Additional work included excavating two 30-ft.-dia. construction shafts 190- and 230-ft. deep, and a 110-ft.-dia. pump station shaft 190-ft. deep. Crews are also constructing four intake structures consisting of surface structures and associated pipelines.
The tunnel supplements an older sewage line and will help prevent raw sewage spills into the river. With substantial population growth occurring in Cobb County, the project is a necessary addition to the area's infrastructure. Early challenges involved limiting blasting operations to specified times and adhering to blast noise restrictions.
- Additional Markets
