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By Harold Cunliffe
Since July, 2002, a remarkable project is being conducted beneath our feet. The Nancy Creek Tunnel has been under construction, stretching from The R. M. Clayton Water Treatment Plant on the Chattahoochee River following Nancy Creek upstream to Johnson Ferry Road. The Tunnel is 16 feet in diameter, several hundred feet deep and approximately eight miles long. Upon completion, waste water from the existing surface trunk lines will be diverted into the Tunnel. This should dramatically reduce spillage into Nancy Creek for many years to come. Two massive tunnel boring machines worked for two years before punching through last summer. Since then, the Tunnel is being finished with a one-foot concrete liner. That liner is now complete from Johnson Ferry Road to the Roswell Road Shaft which is located across the street from Pike's Nursery. Flow was restored in the previously dry "Windsor Road" creeks shortly after the lining was installed beneath. The liner is also complete from Shadowlawn to the R. M. Clayton Plant leaving about 10,000 feet to go. As soon as the Tunnel is lined, a grouting operation is
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conducted that will all but seal the Tunnel from external leaks. There is no danger of leakage out of the Tunnel because the groundwater pressure far exceeds the pressure in the Tunnel. The grouting procedure is now completed 3,000 feet south from Johnson Ferry -- just under Derby Hills. Several intakes are also completed that will divert effluent from the existing surface sewer mains into the Tunnel. The Tunnel should be complete and ready in December, 2005. A pump station located at the R. M. Clayton Plant is now on the critical path and should be completed in January, 2006. These dates are well ahead of schedule and should meet the Consent Decree deadlines, thus avoiding substantial penalties to the City of Atlanta. The Nancy Creek Tunnel Project was budgeted at $180 million. The Tunnel itself will cost $131 million and the Pump Station, $31 million. Design and Management costs are projected to run under $18 million, bringing the project in slightly under budget. This report is Number 11 in a series going back to May, 2002. Previous reports are on NBCA's web site.
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