The final commissioning of Atlanta’s $321.3-million water supply project in December 2020 signified more than just the completion of a five-year effort to bolster the city’s strained water supply resources. Begun amidst the looming specter of potentially devastating droughts and finished in the middle of a global pandemic, the multifaceted project overcame multiple technical challenges to win its race against the formidable opponent of time, thereby heroically securing Atlanta’s drinking-water supply for the next century.
Along with transforming a one-time quarry into a 2.4-billion-gallon raw water storage facility, the project team—led by the construction manager at-risk joint venture of PC Construction and H.J. Russell & Co.—mined five miles of 12.5-ft-dia tunnel through hard gneiss bedrock more than 400 ft below the surface. Blind-bore drilling created eleven 235-ft-deep to 420-ft-deep hard rock tunnel access shafts ranging between 8 ft and 40 ft in diameter. New 200-million and 135-million-gallon-per-day pump stations manage the two-way flow of water from the Chattahoochee River to the quarry to keep the treatment system in balance with demand.