SIOUX FALLS, S.D. (KELO AM) It took about a month of slow but steady progress for a special machine to bore a huge underground tunnel beneath busy Interstate 229 in Sioux Falls.
Sewer pipes big enough to stand up in will be placed in the tunnel to carry away 90 percent of the growing city's wastewater.
City officials on Thursday gave local media a 'look and see' update for the huge $25 million infrastructure project. The two-year project is scheduled to be completed in the fall.
The project includes includes the replacement of a 66-inch-diameter pipe with approximately 1.8 miles of 72-inch-diameter gravity sewer line from west of Cliff Avenue and Chambers Street to the Main Pump Station near I-229 and East Rice Street.
The crossing underneath I-229 is 350 feet long. Tunneling began on July 10 on the east side of I-229 and emerged on the west side of I-229 on August 8. The machine gobbled through at the rate of about one foot an hour. The 72-inch pipe will be placed within the 96-inch casing pipe on rails to ensure the sewer pipe is on the correct line and grade.
“This project has gone extremely smoothly, even including the risks associated with tunneling under a major interstate. Our wastewater infrastructure will be stronger than ever and ready for the continued growth expected for our city,” says Civil Engineer Dustin Posten.