Township tackles sewer issues, approves apartments

A larger-than-expected pipe helped unjam a planned apartment project being held up by sewer capacity issues in Thomson Township.

Josh Evans, an assistant engineer with the township’s contracted engineering company, AE2S, had recommended a halt on any new construction in Thomson Township at the board meeting April 18, because he believed the sewer system there was at or exceeding capacity based on modeling and flow data. At the time, township supervisors had refused to issue a moratorium on new construction, but they did delay a vote on the 22-unit apartment building that developer Gregg Perich of GSP Construction had been planning for more than a year.

But the modeling was based on an 8-inch pipe, and the engineer learned the apartment building would actually be tying into a 10-inch sewer pipe.

Updated models showed the sewer network that serves the proposed apartment building flows at 70 percent of capacity in dry weather with only one segment of the line exceeding the recommended design capacity of 75 percent. The apartment building would increase the flow in West Riverside sanitary sewer by just under 5 percent.

Although Evans still told the board he couldn’t recommend they approve the apartment building, he did suggest that municipalities facing similar sewer capacity issues have allowed growth to continue, but also started immediately on a sewer growth plan and efforts to reduce rainwater and sump pumps draining into the sanitary sewer system.

Supervisors were on board with both ideas, and voted unanimously to allow Perich to extend the existing sanitary sewer main on Evelyn Street to his apartment building in the Southridge Subdivision.

In the meantime, township and engineering staff aim to do what they can to find and eliminate extra rainwater entering the sewer system — known as inflow and infiltration, or I&I — by televising lines, conducting smoke testing and increased home inspections. Leaky sewer pipes should be lined. Sump pumps illegally draining into the sewer system would be detached.

“Anything that we do to reduce I&I in that time will help the system out,” Evans said.

Supervisor David Sunnarborg and township staff planned to continue physically confirming what size sewer pipes exist where.

“We have a lot of I&I, not only on that section, but throughout the township. We have sewer pipes [where] gravity isn’t flowing, in other spots,” Sunnarborg said. “We have a lot of sewer work we want to do this year that will take care of a lot of other problems.”

The township will also continue to plan for the future.

“I’d like to see a sewer growth management program front and center,” supervisor Terry Hill said. “So we’re proactive in upsizing where we need to upsize and moving forward.”

Developing and following a plan to increase capacity in critical areas will allow development to come in “without any fanfare,” said Justin Klabo, also of A2S.

“The biggest thing is being ahead of it; that way, when people come in, it’s a rubber stamp at the point for yourself and your staff,” Klabo said.