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What is the Tunnel Boring Machine?

A tunnel boring machine (TBM) is designed to dig through rocks to create a smooth underground tunnel. The TBM will be used to construct the five-mile long tunnel with a 10-foot diameter from the quarry to the Chattahoochee River.

Why do we need a TBM?

The tunnel boring machine will be used to build the tunnel connecting the Chattahoochee River, Hemphill Water Treatment plant and the new 2.4 billion gallon water storage facility. The Water Supply Program will provide the City with a minimum water supply of 30 days.

What impact will tunnel construction have on my property?

Nearby residents can expect minimal impact of traffic during the arrival of TBM parts. The construction will not pose any local noise impacts.

How big is the TBM?

The tunnel boring machine is 12.5 feet in diameter, but because the tunnel will have a concrete liner, it will be 10 feet in diameter.

What is the estimated cost of the Water Supply Program?

The estimated cost of the Water Supply Program is $298,073,432. For context, the cost to the City of Atlanta businesses, including the world’s busiest passenger airport, if we were to lose our water supply would be $100 million per day.

How much is a TBM?

The estimated cost of the TBM is $11.6 million.

Who may I contact for questions or concerns regarding the project?

If you have additional questions or concerns, please contact the DWM Office of Communications and Community Relations at 404-546-3200. You may also visit our website at and our Facebook and Twitter pages at @ATLWatershed for more project information and updates. Join the online conversation with the hashtag #H2O4ATL.

Where was the TBM coming from?

The TBM will travel to Atlanta from Solon, Ohio on 78 tractor trailers. It will be assembled on the floor of the quarry.

Who will perform the work?

PC/Russell, Joint Venture is the selected Construction Manager at Risk for the Water Supply Program. PC Construction, along with partners Atkinson, Stantec, and Robbins, are currently preparing the quarry work site, including assembling the tunnel boring machine.

When does the TBM arrive?

The TBM began arriving June 29 on 78 tractor trailers. The TBM consists of 28 different parts that will also arrive by the end of July.

When will the TBM be assembled?

Assembly of the TBM will begin in July and is slated for completion by September. Once finished, it will be 400 feet long – longer than a football field!