An 8-ton German tunnel borer gripped the rock so its own cutting wheel couldn’t roll it over, cut three 51-inch water intakes under a Georgia reservoir and came out through the lakebed three times for
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Key Points:
- Douglas County, Georgia, is expanding its Dog River Reservoir by raising the dam 35 feet to more than triple its water storage capacity, addressing concerns about drought resilience identified over a decade ago.
- Huxted Trenchless completed three 51-inch microtunnel water intake tunnels using a specialized 8-ton Herrenknecht AVN1000HR machine, designed to bore through hard rock and prevent rotation from torque via hydraulic grippers.
- The tunnels end at the reservoir bottom, requiring dual bulkheads to prevent flooding during machine recovery by divers, a complex process similar to previous water intake projects in other states.
- The new intake conduits will feed a pump station with two 2,500-horsepower pumps, supporting a water storage increase from 1.9 billion to 6.5 billion gallons, maintaining daily supply at 23 million gallons.
- The $390-$440 million project, the largest public infrastructure effort in Douglas County, is expected to be completed by 2029, with significant recreational area closures due to rising water levels.
