Citizen Energy Group’s DigIndy Tunnel System has been under construction for more than a decade and is finally nearing completion. But many still have questions about the $2 billion project.
The company invited Mirror Indy and several other local media outlets to tour the Southport Deep Rock Tunnel Collector Pump Station, the first rock tunnel dug for the project back in 2012.
Here’s what we found out.
What is the DigIndy Tunnel System?
The DigIndy Tunnel System is a network of 28 miles of tunnels throughout the city. Two hundred and fifty feet underground, they were built to collect 5 billion gallons of sewage and rainwater every year.
That’s enough to fill Lucas Oil Stadium 17 times.
The 18-foot diameter tunnels have begun acting as a storage tank, preventing the collected wastewater from entering local waterways and polluting them with bacteria, viruses, debris, industrial chemicals and other hazardous substances.
Besides the tunnels, the DigIndy project also included the construction of about 32,000 feet of new sewer.
“We have sewers from the 1880s and they’re in disrepair. They’re collapsing,” said Mike Miller, manager of engineering for Citizens Energy Group.
Citizens Energy has found city pipes made of wood that may date back to the late 1800s or early 1900s. They are kept in service until they fail and are then replaced with modern service lines made of PVC or other materials.
The sewage and rainwater collected in the sewer systems is then transported to the DigIndy Tunnel System through large drop shaft structures, essentially 250-foot pipes, throughout the tunnel system.
Miller said the structures are the pieces being built along Fall Creek.
What happens to the water once it’s collected?
Once the sewer water is collected in the DigIndy tunnel, it’s taken to the Southport Deep Rock Tunnel Collector pump station located on the grounds of the Southport Advanced Wastewater Treatment Plant.
The wastewater goes through a screen and grit shaft, essentially a large sieve, where large debris is collected and removed.
“If you can flush it down the toilet or get it down a storm drain, it’s going to get here, and we don’t want that to get into the pumps,” Miller said. “For the most part, by the time it gets here, when we pull it out, it mostly looks like brown sludge. Most of it is not recognizable, except for maybe a plastic soda bottle or a Barbie head, G.I. Joe — whatever little kids like to put down the toilets.”
Once the debris is removed, the collected water is pumped about 300 feet upward to the Southport Advanced Wastewater Treatment Plant, where contaminants are removed before being discharged back into the White River.
Why was DigIndy necessary?
Indianapolis used to operate its own water and wastewater utilities until 2011, when Republican Mayor Greg Ballard’s administration sold it all to Citizens Energy Group.
That decision came after former Democratic Mayor Bart Peterson’s administration signed an agreement in 2006 with the Environmental Protection Agency. The agreement settled a lawsuit that had alleged the city violated the U.S. Clean Water Act by allowing too much raw sewage into public waterways.
“The system was actually designed to overflow into the local rivers during periods of heavy rain, so that we don’t back up into houses, businesses and streets during wet weather events,” Miller said.
The agreement required the city to implement long-term plans to stop 97% of the sewage overflows in the Fall Creek watershed and 95% in the White River watershed.
When Citizens Energy Group bought Indianapolis’ water utility, it took on the obligation to fulfill the agreement.
What resulted was the DigIndy Tunnel System, which began construction in 2012.
Recent water main breaks were unrelated
DigIndy construction is “completely unrelated” to two recent water main breaks on the east and west sides, according to Ben Easley, a spokesperson for Citizens Energy Group.
In March, roads flooded near 22nd Street and Dr. Andrew J. Brown Avenue. In June, they flooded near Lynhurst Drive and Morris Street.
“Our recent water main breaks that have been in the news are completely unrelated to this,” Easley said. “That’s the potable water that goes to your house. (DigIndy) is related to the sewage that comes out of your house.”
When will construction be completed?
Currently, DigIndy construction is happening along Fall Creek and Pleasant Run.
According to Citizens Energy, the entire project is expected to be completed before the end of the year.
Construction on four out of the six main tunnels has been completed. The Fall Creek Tunnel and the Pleasant Run Tunnel will be connected to the DigIndy system within the next few months.
Once construction is completed, the project will transition into a five-year performance monitoring phase, where the system’s effectiveness will be evaluated.
For more information about the DigIndy project, head to Citizen Energy’s DigIndy site.
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Mirror Indy reporter Enrique Saenz covers west Indianapolis. Contact him at 317-983-4203 or enrique.saenz@mirrorindy.org. Follow him on Bluesky at @enriquesaenz.bsky.social.
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