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Reduce flooding from backed up sewers? There's an app for that

a top down view of two people wearing baseball hats and safety vests standing beside a storm water retention pond. One is using a phone. The other is handling a tall metal sensor.
UM Civil & Environmental Engineering
Researchers from the University of Michigan's School of Civil & Environmental Engineering install sensors to monitor water levels in a storm water retention pond.

In areas where floods were once rare, some neighborhoods are now flooding repeatedly. Storm water sewers are being overwhelmed by more intense storms.

Most of the solutions call for big pipes and expensive construction.

But a group of researchers wants to instead get cities to use their current systems better with an app.

Kerkez Branko and a team of researchers at the University of Michigan are helping wastewater managers use internet-connected sensors to better manage sewers.

The idea behind the research is fairly simple. Even when there’s a lot of rain, there are parts of a combined storm water and sanitary sewer system that aren’t full. There is storage capacity. The problem is you have to know where.

And it's going to be different for every system.

“Some places are dealing with very sort of large scale flooding, while others are dealing with water quality impairments. Here in the Great Lakes region, we have a confluence of those,” said Branko Kerkez, an Associate Professor leading a group of Ph.D. students from the University of Michigan’s College Civil and Environmental Engineering.

You’ve heard of self-driving cars. They are engineering self-operating sewer systems.

Kerkez says a rainstorm doesn’t hit a city the same way everywhere at the same time.

“So, a good example is it's raining a lot on one part of town, it's not raining that much in another part of town, so you might have storage assets that are not full all the time,” Kerkez explained.

He and his team have been experimenting with cheap monitors hooked up to the internet. By looking at a computer screen or even a phone, sewer system operators can see what’s going on.

Just like a car that self-driving steers itself. Given changing conditions, water systems in the future may be able to control themselves dynamically in response to these inputs
Branko Kerkez, University of Michigan

“What are the conditions? Do I have extra storage over here? Can I close that valve to allow another part of the system to drain out? Just like a car that is self-driving steers itself. Given changing conditions, water systems in the future may be able to control themselves dynamically in response to these inputs,” Kerkez said.

The Washtenaw County Water Resources Commission has been working with Kerkez and his team to install the sensors. Harry Sheehan is the Chief Deputy Water Resources Commissioner.

“This cost $500, you can plunk them down anywhere, right, and it's got a solar panel and it's got a modem in it, so it can tell you what the levels of water are very quickly. So, you know, it's cheap, it's low maintenance, it gives you lots of information,” Sheehan said.

For Washtenaw County, the sensors are helping to identify where there are choke points. They can install the monitors in storage ponds and the creek that connects them. After a couple of years, they’ve gathered lots of data about how the creek and ponds behave during heavy storms.

“And when we hire an engineering consultant to do a modeling to see what can be done there and what the design should look like. They already have the data, right? So, you've already collected $30,000 worth of data for a few hundred bucks,” Sheehan said.

view of a pond in Ann Arbor on a fall day. There is a sign and tall, brown brush plants in the foreground. The water is in the distance with a tree line in the background
Lester Graham
This pond at Mary Beth Doyle Park in Ann Arbor is one of a series of retention basins that slow the rush of water and allow the stuff washed from parking lots and streets to settle out before the water goes into the Huron River.

That’s going to help Washtenaw County figure out how to better manage storm water and save some money.

Sheehan noted even the water soaking into the ground in rain gardens can be monitored to see if they’re working well.

In a system like the one in Washtenaw County, much of the storm water runoff goes to rain gardens and ponds.

Most of these ponds were excavated in the 1960s and 1970s, and not a lot of thought was given to the aesthetics at the time. A collaborator with Kerkez and his team finds that acceptance of a smart storm water system by the public depends on whether it seems to fit in the neighborhood.

“How the edge of the smart storm water pond appears, and that’s affected by the steepness of the slope for constructing the pond, as well as how much edge there is beyond that slope that has water in it, where you can plant and what kinds of plantings are there,” explained Joan Nassauer, professor in the School for Environment and Sustainability at the University of Michigan. She conducted surveys of in cities with and without smart storm water systems.

She says along with how it looks there are other concerns.

“Perception concerns are partly about amenity, partly aesthetics, but they’re also very much about perceived safety,” she said. "Would an automated system lowering and raising the level of water be dangerous to kids playing in the neighborhood? The water rises and falls naturally anyway, but the perceptions of the residents are still an important consideration."

The Great Lakes Water Authority operates water and wastewater systems for a big chunk of southeast Michigan including the City of Detroit and Wayne, Macomb and Oakland counties.

There, researchers are not only putting in the sensors in sewer pipes, but they’re getting more precise real time information about where it’s raining. They’re looking at ways to remotely activate valves and inflatable dams in the pipes to direct water where they have storage capacity. That will help to avoid floods in streets and neighborhoods downstream as well as to prevent dumping untreated or partially treated sewage into the Detroit River.

I still can't believe that we can manage sewers and that not only do we manage sewers, but that artificial intelligence is being used to help us manage sewers.
John Norton, Great Lakes Water Authority

John Norton is Director of Energy, Research & Innovation at the Great Lakes Water Authority. He says in just a few years, sewer systems could be controlled by artificial intelligence.

“What we need is controls—to build an automatic controls—well, we have that. We need sensors to figure out what's going on. Like you pointed out, there's rainfall sensors, there's actual predictions using radar and NOAA data. So there's a variety of different sensors and how do we integrate all that in? And then there's the algorithms themselves.”

Norton says they could have a system like that in place as soon as two or three years from now. Other cities such as Cincinnati, Ohio and South Bend, Indiana already have similar systems that are models for the nation.

“I still can't believe that we can manage sewers and that not only do we manage sewers, but that artificial intelligence is being used to help us manage sewers,” he said.

But the smart sewers won’t solve everything.

As climate change continues, more big concrete pipes and underground storage will be necessary in some places. But these systems will make what wastewater systems communities have right now work more efficiently and do it quicker and cheaper.

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