By Stacy Jacobsonsjacobson@abcnews4.com
CHARLESTON, S.C. (WCIV) -- From the construction above ground, you may never realize what's below Concord Street in downtown Charleston, but 140 feet below the street are a series massive, 12-foot-diameter tunnels.
"We did this excavation in approximately two months," contractor Cliff Kassouf said.
The walls of the $25-million project are wooden now but eventually they'll be filled in with concrete. It will create the infrastructure for Charleston's new drainage system along the Market.
"The tunnel's going to collect all the storm water and then carry the storm water to the pump station," said Laura Cabiness, director of public service for the city of Charleston.
Construction crews used a special machine to plow the path of the tunnel for almost the entire length from Concord Street to the end of Market Street.
Cabiness has been with the city for more than 20 years. She said the project has been a huge challenge, and they're one of the first sea-level cities to do it. But now they're ahead of schedule.
"Those nasty afternoon thunderstorms will no longer flood the Market out and business will be able to continue. It'll dry up much faster," Cabiness said.
The project should be finished in 2016. It's separate from the Crosstown drainage project.