Rainfall causes continuous overflow of sanitary sewers into Lake Manistee reported on Sunday

MANISTEE — Rick Mohr, assistant manager of the Manistee Public Works Department, shared an initial report of a sanitary sewer overflow via email Sunday afternoon.

Manistee had a sanitary sewer overflow that began at 4:30 a.m. Sunday, the email said.

Mohr noted that the overflow was due to heavy rain.

A final report should be submitted once the overflow has ceased and bacterial testing results are complete on the receiving waters.

Typically, final reports show the number of inches of precipitation and the number of gallons of diluted raw sewage that overflowed into Lake Manistee.


The current three-part $19 million sewer pipeline project at the Manistee Treatment Plant would limit sanitary sewer overflows. Earlier plans indicated that it should end next month.

File photo

A story of excesses

Due to capacity and weather events such as rainfall that cause an influx of sewage, the Manistee sewage treatment plant cannot always handle the additional sewage.

In these situations, excess untreated sewage is dumped into Lake Manistee.

The plant is located at 50 Ninth St. and after a discharge, staff perform downstream sampling for E. coli at five sites to ensure that E. coli does not exceed 300 per ml.

Sanitary sewer overflow events must be reported to the public – but are legal – discharges are diluted and not a new occurrence.

According to previous interviews with Manistee Public Works Department Manager Jeff Mikula, overflows have been reported for the past 30 to 40 years.


Details of the overflow are being reported to the city, health department, and state. The News Advocate also reports details of the overflow events.

Over the past 30 years, Manistee has invested nearly $40 million to eliminate raw sewage discharges into the Manistee River.

The current three-part $19 million sewer pipeline project at the Manistee Treatment Plant would limit sanitary sewer overflows.

According to a previous email response from Mohr, spillovers could still occur after the work is complete.

“The retention ponds being constructed will hold a total of 6 million gallons. If a rain event is large enough to fill all three reservoirs totaling 6 million gallons, we will overflow to the lake,” Mohr explained. “The big difference is that it will be partially treated and chlorinated. It would most likely take a 25, 50 or 100 year storm to cause an overflow.

The new construction would mean that when flows exceed what the plant can handle, the flows would be dumped into three separate aboveground tanks where they could be stored until flows diminish. When the plant is back to capacity, wastewater workers can drain the tanks and run the streams through the treatment process.

Earlier estimates indicated that the project should be completed by some time in August.

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