St. Clair Shores takes steps to separate combined sewers

By: Kristyne E. Demske | St. Clair Shores Sentinel | Published October 27, 2021

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ST. CLAIR SHORES — Taking the first step toward the separation of combined sewers in the Martin Drainage District, City Council approved a flow metering plan to determine how much storm water is within the lines during a rain event.

There are three districts in St. Clair Shores where storm and sanitary sewers are still combined. Hennessey Engineers investigated which of the three would provide the easiest way to implement a sequential phasing plan of sewer separation to reduce combined sewer overflows and basement flooding.

The Martin District had some advantages, according to Hennessey Engineers Vice President John Hennessey — it is a true combined system with the option to discharge into the Alexander Drain. Hennessey said Macomb County officials have given the go-ahead for the city to discharge into that drain, provided it can handle the excess flow.

That is why the engineering firm was in front of City Council in October seeking approval for a flow-metering plan that would install 11 meters in the combined sewer system to determine flow during rain events. Meters would be installed on the sewer along Frazho Street at Winton, Larchmont, Grant, Ursuline, and Princeton streets; at Bon Heur Street between Little Mack Avenue and Manhattan Street; at Madison Court and Lakeland Street; and on the sewer along Manhattan Street at Frazho, Sunnydale and Alexander streets.

The meters will be in place for about eight weeks to capture several different types of rain events.

“Then, we can model the system and come back to you at a future date with a more detailed plan,” Hennessey said Oct. 4.

The project has a cost not to exceed $48,500 and will be paid for using American Rescue Plan Act funding, as will the future costs of the sewer separation.

“This body dedicated money from the ARPA. Part of the money is to go to sewer separations,” Mayor Kip Walby said. “We’re, kind of, in essence, taking this next step to do some engineering as we look, hopefully down the road, to do some construction in 2022 to start separating them.”

With the results of the flow-metering study, Hennessey said they will be able to develop a comprehensive capital improvement plan to do the first phase of the separation.

“This is the very first phase of that — (a) road map for us to continue to do that as additional funding becomes available,” he said.

The fact that St. Clair Shores is three-quarters of the way separated already is good for a city of its age, Hennessey said, but separating more of the sewers will reduce the CSOs from the city.

“This is the way we were built, the older communities,” Walby said. “It’s a good use of ARPA. It’s an expensive process to (separate) the entire community.”

If too much water needs to flow to the Alexander Drain, the city would need to construct a new drain to accommodate the new flow.

Councilwoman Candice Rusie questioned whether eight weeks would provide enough reliable and accurate data. Hennessey said that October and November typically have enough rain events to provide accurate data.

“If we find that we’re not getting any readings through (that time period), we’ll be back before council,” he said. “Most metering is always done from the end of September toward December because that’s when you get really good rain events. You’ll get some good runoff from the ground.”

City Council unanimously approved the motion to move forward with the flow monitoring.

“It’s the right thing for the lake to reduce that,” Councilman John Caron said. “It may help get the county to where Martin doesn’t need to discharge during heavy rain events. That’s our goal.”