"Deep Rock Tunnel" to provide cleaner water to Indianapolis

The Deep Rock Tunnel will replace "combined sewer overflows," under the city.
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Citizens Utilities is asking for water and sewer rate increases of more than 25 percent in the next year - and the rate hike requests won't end there. Some people estimate increases will top 400 percent by 2025.

It's a lot of money - billions of dollars - but the money will go to solve a costly environmental problem more than 100 years in the making.

It started at the turn of the last century, when civil engineers in Indianapolis decided to build "combined" sewers - a system that handles both waste water and rain water.Usually, it's not a problem. But when it rains, even as little as a quarter-inch, it turns into a big problem. The water treatment plants can't handle the volume, so the sewers overflow - sending the excess water directly into central Indiana waterways. The combined sewer overflows (or CSOs) dump hundreds of millions of gallons of raw sewage into rivers and streams. That was apparently acceptable in 1913, but in 2013, it is not.

"Back then, rivers running through major cities were sewage pits," said retired Eli Lilly researcher Richard Van Frank.

Van Frank made a career out of studying parasites and water-borne bacteria. When he retired in the 1990s, he turns his vocation into an avocation. He has been pushing the city and the utility company to contain CSOs ever since.

"It's not sustainable," he said, "because that raw sewage contains all sorts of disease-causing bacteria, viruses, and parasites."

The Environmental Protection Agency also knows it's not sustainable and is forcing Indianapolis to get ahold of the problem. To find the city's response, you have to do more than just scratch the surface. You have to go down, 250 feet into a hole on the south side near the Southport Water Treatment Plant. This is where you will find the beginning of the Deep Rock Tunnel Project.

Technicians and professional miners have been working below the surface here for more than a year to prepare to dig a tunnel that will hold raw sewage that used to flow straight into local waterways. When it is finished, the Deep Rock Tunnel system will hold 250-million gallons of raw sewage until two local water treatment plants can process it.

"We're creating, more or less, a bathtub for the whole county - for the center part of the county - as a combined sewer," Citizen's Utilities Construction Manager John Morgan said.

It's an ambitious project and it requires some hard-core equipment.

Enter a heavy-duty, high-tech tunnel boring machine, that delivers 3,376 horsepower to a solid steel 20-foot cutter that can drill through solid rock. The giant disc spins at only nine revolutions per minute, but it has 39 cutter heads that chip off the fist sized chunks of rock that are collected by one of six spinning collection buckets and then sent to a conveyer belt that will carry it back to the surface. It removes a thousand tons of rock per hour, but even operating 24 hours a day Monday thru Friday (weekend will be for maintenance), the project will move at a slow pace.

"150 feet is an average day. A good day will probably be 200-250 feet a day, maybe more," said project manager Stuart Lipofsky.

It will be a slow grind and it has already taken workers more than a year to get to this point. They loaded the tunnel boring machine piece by piece into a 300-foot starter hole and assembled it on site. All of the systems must be checked and rechecked.

Lipofsky has been through the punch list several times. It's not enough to cut through the deep rock, the machine has working sensors for methane gas and water - either of which can cause problems for the drilling. If the machine hits either one, it shuts down automatically. The operator watches the progress on a series of computer screens and gauges. If anything is offline, the system needs to be re-calibrated.

The job is complex, but Lipofsky has successfully completed projects like this before.

"Every project is unique," he said. "The concept is not unique, but every project is unique and has its own set of challenges to get it done."

In the last decade, deep rock tunnel projects have been started in Atlanta and Chicago. It's a proven technology.

Expensive, yes. But also a long-term fix.

In more than two decades as an active environmentalist, Van Frank has been critical of utility rate hike requests in the past, but not this time. He says customers will feel the pain of the hikes, "but they've been paying an unrealistically low rate for many years - more than 30 years - because they were satisfied with having raw sewage flow through the streams in Indianapolis."

The Environmental Protection Agency is no longer satisfied with CSOs in Indianapolis. By agreement with the city, the Deep Rock Tunnel system will eliminate up to 99 percent of the CSOs. It is the ultimate long-term fix.

The first phase of the Deep Rock Tunnel project will run about 7.5 miles, connecting the Southport Water Treatment Plant with the Belmont Water Treatment Plant, between Harding Street and Kentucky Avenue on the southside.

The schedule calls for putting the first phase on line in 2017, then extending the holding tunnel up to near the State Fairgrounds. By 2025, three more tunnels will collect with the Deep Rock Tunnel to complete the project.

When it's all done, 25 miles of tunnel will run under Indianapolis. Since the entire project will be 250 feet below the surface and out of sight - you will probably never know that construction is going on. The only place it will really be noticeable is on your monthly water and sewer bill - in the form of higher rates - and in central Indiana rivers and streams in the form of cleaner water.