Under the direction of the Engineering and Records Division, the 5 Year, $640 million Capital Improvement Plan places Cobb Water System in the forefront of financial and capital planning efforts in the Southeast. More than 100 projects are identified and tracked. Typical projects include water and sewer line repairs/replacements and sewer line extensions. To view a map of current Cobb Water System construction projects in PDF format, follow the link at the top of this page.

South Cobb Tunnel

The South Cobb Tunnel is the largest capital improvement project in Water System history. A $305,000,000 construction contract was awarded to Shea-Traylor J.V. (a joint venture of J.F. Shea Construction and Traylor Brothers) on March 11, 2008. Construction will begin in June 2008 and will take six years to complete.

This project will provide needed long-term sewer conveyance capacity and equalization for the Sweetwater Creek and Nickajack Creek basins located in western and southern Cobb County, and will allow Cobb to eliminate two major pumping stations and about 87,000 linear feet of ageing sewer line and force main.

The South Cobb Tunnel project entails constructing a six mile, 27-foot excavateddiameter tunnel located in hard rock, with depths ranging from 150 feet to 400 feet. Most of this main tunnel will be excavated using a large tunnel boring machine similar to the picture on the right. Several six-foot diameter tunnels and one ten-foot diameter tunnel with lengths ranging from 100 to 3,200 linear feet will be constructed also.

The main tunnel alignment will begin near the intersection of Maxham Road and Old Alabama Road continue southeast along the county line then turn east just north of I-20 and continue east to the South Cobb WRF. To view a map of the project click here.

The project also includes building a deep lift station with a capacity of 130 million gallons per day at the South Cobb Water Reclamation Facility (WRF) to convey wastewater flows from the tunnel to the plant for treatment.

The Water System completed the Chattahoochee Tunnel, a six and a half mile tunnel with an excavated diameter of 18 feet, in 2004. The Chattahoochee Tunnel project was very successful and has been operating as expected. The Water System fully anticipates a similar level of success on the South Cobb Tunnel project.

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Woodbine Station

The Water System continuously inspects our sewer system to identify problems which need to be corrected to ensure the integrity of our system and to protect public property and the environment. We identified numerous sewer line defects in Woodbine Station Subdivision located off Sandy Plains Road. Repairs are required to stop groundwater from entering the sewers, to remove roots intruding in the pipes, and to prevent lines from collapsing. These repairs will extend the life of the sewer lines and help to prevent blockages which can cause sewer overflows.

The construction will be completed in three phases. First, the easement clearing contractor will begin clearing some of the easements in early April 2008 so that sewer lines can be accessed. Second, K.M. Davis Contracting will begin making repairs in late April 2008. Most of these repairs will be point repairs on the lines which only require digging at the location of the defect and repairing that one place. Seven lines in the subdivision are in such poor condition that the entire line between manholes needs to be replaced. These repairs will be completed by October 2008. Third, the Water System will hire a contractor to install a lining in the sewer lines in a few locations. Lining can be accomplished by accessing the manholes, so it does not require excavation. This is the least invasive way to repair sewer lines, but unfortunately all problems cannot be corrected by this method.

Click here for a link to the map showing the approximate location of the point repairs and line replacements (same ditch relay).

The pictures below are examples of defects which will be repaired.

Sewer tap protruding into line, and roots entering the connection.	Hole in sewer line.	Broken pipe.
Offset joint.	Crack in pipe with roots.	Heavy roots blocking line.

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R.L. Sutton WRF

After construction of the R.L. Sutton Water Reclamation Facility new liquid process treatment system was completed in December 2004, construction began on a new solids processing facility in February 2005. The facility includes a Solids Handling Building that houses two new fluidized bed incinerators and a dewatering system consisting of four centrifuges, cake pumps and screw feeders, sludge silos, polymer system, and controls. A sludge thickening system, odor control, sludge feed system, and gravity thickeners complete the construction scope. Construction should be completed by October 2008 at a cost of $56,890,000.

Above: Fluidized-bed     Incinerator.     Left: Solids Handling     Building.

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