German microtunneling machine anchors to rock to bore water intakes under Georgia reservoir
Huxted Trenchless completed three 51-inch water intake tunnels under the Dog River Reservoir in Douglas County, Georgia, using an 8-ton Herrenknecht AVN1000HR microtunneling machine. The project aims to raise the dam by 35 feet and triple storage capacity to 6.5 billion gallons by 2029. The machine required hydraulic grippers to prevent rotational torque from rolling the unit over during hard rock excavation. Each tunnel ended at the lakebed, requiring divers to recover the equipment after the machine broke through the water. The new intake feeds a pump station with two 2,500-horsepower vertical turbine pumps, ensuring the county’s primary drinking water source can sustain 23 million gallons daily through severe droughts.