The City of Atlanta is converting an over-a-century-old quarry into a 2.4 billion-gallon raw water storage facility. The system consists of a deep hard rock tunnel, two deep pump stations, two dropshafts and multiple connecting adits and shafts. Bored with a TBM from tunnel portal at the quarry base, the tunnel is approximately 24,000ft long, 250ft to 450ft deep, 13ft in bore diameter, and is partially concrete lined with modified contact grouting to control water infiltration/exfiltration. CFD modeling is performed for the pressurized system. Various shaft construction techniques are used, including drill & blast, blind bore drilling and raisebore drilling.
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