Atlanta Water Supply Program Phase 1A, Bellwood Quarry Tunnels and Shafts
Atkinson is constructing a water conveyance and storage tunnel connecting the Bellwood Quarry to the Hemphill Pump Station and the Clayton Site adjacent to the Chattahoochee River. Once complete, the project will increase the City of Atlanta’s water storage capacity by approximately tenfold. Phase I construction includes a 5,569-foot long, 10.5-foot diameter TBM tunnel through hard rock from the Bellwood Quarry site via a portal launch to the Hemphill Pump Station.
The Bellwood Quarry site includes four shafts ranging from 200-feet to 400-feet deep with diameters ranging from 20-feet to 30-feet. Each is finished with reinforced cast-in-place concrete placed both top down and bottom up—with associated hand-mined adits connecting the shafts to Bellwood Quarry. At the Hemphill Pump Station, Atkinson's underground professionals make the connection to the tunnel via five, 9.5-foot diameter, blind-drilled pump shafts lined with steel casings. Due to the close proximity of our work to the Atlanta City Water Works Reservoir No. 1—the primary water source for Atlanta—Atkinson installed all necessary modifications prior to drilling.
Phase 2 of this project extends the TBM tunnel to the Clayton Site. At the Clayton site along the Chattahoochee River, crews will install a 30-foot diameter, 350-feet deep shaft that will be the exit location for the TBM. This shaft will also have a reinforced, cast-in-place lining.
Atkinson is self-performing all work activities with support from a local Joint Venture partner, Technique Concrete Construction. Additionally, Atkinson is providing design phase services to verify project constructability.