INDIANAPOLIS, Ind. - The city of Indianapolis has a combined sewer system underground, meaning both storm water and waste water (sewage) flows through the pipes.
It's an old system that was built more than 100 years ago and can only take so much.
"When we have combined sewer overflows (CSOs), we have raw sewage entering our waterways," said Laura O'Brien, the corporate communications coordinator for Citizens Energy Group. "When that happens, coming into contact with it, especially hand to mouth contact, swallowing the water, there's a risk of contracting something like e.coli, so you want to avoid those waterways when we have heavy rain events."
Citizens Energy said it does not take much rain to alert the company's environmental stewardship staff to send out a public notice. O'Brien said that will happen after we receive a quarter of an inch of rain. Indy received 3.85 inches of rain on Saturday.
"To let people know, 'Hey, you're not going to want to go near these bodies of water until the rain has slowed down,'" O' Brien explained of the alerts.
Currently, crews are working to complete the 28-mile DigIndy tunnel project. When it is complete, the vast majority of sewage will not reach the waterways.
"We'll be able to prevent up to 99% of that sewage from entering our waterways annually, or up to 6 billion gallons annually," O' Brien said.
The crews have 10 miles of the tunnel complete. That has stopped over 1.2 billion gallons of raw sewage from reaching the water. Citizens said in a May news release, the project is ahead of schedule and $400 million below its original budget.
"We'll have drop shafts, and the combined sewage will enter into the drop shafts, it will go down into the tunnel, and the tunnel will act as a huge holding vessel for all of that combined sewage and storm water and rain water," O' Brien explained. "It will stay there until we have capacity at one of our waste water treatment plants. As part of DigIndy, we've already more than doubled the capacity at those two treatment plants."
DigIndy is working in compliance with a federal consent decree with the U.S. Environmental Protection Agency, the U.S. Department of Justice and the Indiana Department of Environmental Management.
O' Brien did add that the drinking water is safe, and the rain has no impact on the efficacy of it.