Dubuque smoke testing to find sewer system leaks - KWWL - Eastern Iowa Breaking News, Weather, Closings

Dubuque smoke testing to find sewer system leaks

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Cracks in Dubuque's sanitary and storm sewers are leading to overflows and problems for some homeowners.

The city is trying to smoke out the issue that's costing taxpayers thousands of dollars every year.

Thursday morning, a crew with the city's engineering department was at Dubuque Senior High School, pumping a non-toxic smoke down one sanitary sewer connection and watching to see where the smoke leaked out in other spots.

Some smoke leaked out where it was supposed to, such as roof vents connected to the sanitary sewer. Other places, however, had smoke pouring out where there should have been none. Some smoke even seeped up through the grass, evidence of a crack or loose seal in the pipe buried below.

The leaks are costing taxpayers money. Rainwater, instead of being directed to the river via the storm sewer system, is leaking into the sanitary sewer system thanks to cracks and loose seals and causing problems such as sanitary sewer overflows during heavy rain events.

Dubuque's engineering department established the Inflow and Infiltration program back in 2011 as part of an agreement with the U.S. Environmental Protection Agency and Iowa Department of Natural Resources aimed at tackling a burdened sanitary sewer system.

Nick Connolly is an inspector with the Inflow and Infiltration program. He was on site at Dubuque Senior High School Thursday morning and explained why a crack in a storm sewer pipe is problematic.

"When it rains, the water can also follow that crack down and get into the sanitary sewer system, and that's where we're seeing the excess water getting into the sanitary sewer system," he said.

Crews conducted smoke testing the day before at Clarke University, just down the street from Dubuque Senior High School. Connolly said that's because the entire area has problems with sanitary sewer overflows in heavy rain events and attributes it to rainwater leaking into the sanitary sewer. The schools are two of the biggest contributors to the sewer systems in that area.

"During the last rain event, we went out and were just kind of looking at manhole lids, and we noticed a higher amount of flow that probably should be coming, so we knew something was going on," Connolly said.

Jonathan Brown is manager of Dubuque's Water and Resource Recovery Center. He said the inflow and infiltration problem can triple the rate of water flow coming into the treatment center during a heavy rainstorm, from eight to 10 million gallons per day up to 30 millions gallons per day.

"We're treating a lot more water than we need to treat," he said, adding inflow and infiltration is also the cause of sanitary sewer overflows, which create public health risks.

Clean-up and water treatment, of course, don't come free, thus the added cost to taxpayers.

Connolly said Dubuque is not alone in this. Leaks in sewer systems are just part of aging infrastructure in old cities.

Dubuque will be smoke testing some residential areas in coming weeks. Connolly said residents in those areas will be given notice a day or two ahead of time.

In residential testing, finding smoke inside the home can indicate a problem.

"If they're getting smoke into their house, that means they have bad plumbing," Connolly said, "so they're actually running more of a chance of getting sewer gas into their houses, which is methane or carbon dioxide, you know, just waste gases."

He said people who see the non-toxic smoke filtering into their house during residential tests should call the city of Dubuque's engineering department. A phone number will be listed on the alerts people in the area receive. Connolly said the testing will take place around Peru Road in northern Dubuque.

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