Metro Water Services started inspecting underground sewage lines on Monday to assess damage after the Christmas Day bombing. To do it, the agency hired a contractor to send remote-controlled cameras into the pipes.
Spokesperson Sonia Allman says the agency will inspect about 12,000 feet of sewer line by the end of the week.
Some of the pipes are made of brick or concrete. But it’s the oldest ones — made of clay and installed in 1903 — causing the most concern.
“When you have older clay pipe, especially that type of vibration could have caused it to fail,” Allman said.
The clay pipes make up at least 3,300 feet of sewage lines in the area. However, that number is likely to go up, since there’s about 5,300 feet of line that the agency has listed as “unknown” material — likely additional clay infrastructure.
This is one of the cameras that will be used to inspect the underground sewer pipelines in the area of the Christmas Day bombing.
— Sergio Martínez-Beltrán (@SergioMarBel) January 4, 2021
To assess the potential damage, Metro is sending in a small camera that rolls on wheels with a headlight. It looks a little bit like a miniature version of the WALL-E robot. As it travels, some lines may need to be cleaned, requiring powerful jets of water and powerful vacuuming.
The cameras will record their underground journey so Metro engineers can decide which pipes need replacement. This inspection will cost $75,000 with contractor Ace Pipe Cleaning.
But the repair cost could increase substantially if they find a lot of damage, potentially requiring pipe replacements in the heart of downtown.
“If we had to dig up the street to completely replace them, it would be quite an impact to the city,” Allman said. “We want to use any options or methods that we have to lessen that impact.”
Thus far, Metro doesn’t believe there was any damage to the public water system. The focus is on sewage lines.