SHEBOYGAN - A rapidly eroding shoreline is beginning to expose a major sewer line on Sheboygan’s south side.
The pipe is a “critical piece of infrastructure,” said David Biebel, the city’s director of public works.
It carries nearly 50% of all of the sewage going to the city’s wastewater treatment plant, including most of the City of Sheboygan’s sewage as well as some from the town of Sheboygan and outlying areas, he said.
Reinforcing the pipe, which is more than 90 years old, became a priority for the city because of rising water levels on Lake Michigan — which have increased 3 to 4 feet over the past four years.
A $10 million construction project set to take place next year will maintain access to the sewer line and regrade the shoreline from King Park to the wastewater treatment plant.
The project will be paid for using the city’s American Rescue Plan funds, federal COVID-19 relief funds given out this year.
Officials worried water levels could damage or compromise the sewer line
The southside sewer line was built in 1930, when Lake Michigan’s water levels were approximately 3 feet lower than they are today, according to data from the National Oceanic and Atmospheric Administration.
Annual average lake levels rose from 2014 to 2020, and recently, local officials have become concerned that erosion could damage or even compromise the pipe, Biebel told The Sheboygan Press.
“There are manhole structures to access the pipe that are very close to the lakeshore, that under high water conditions can be overtopped with wave action and during the winter time can get ice being shoved into them, which can cause damage,” he said.
Another concern is that many areas have become inaccessible to equipment because of the shifting topography of the lakeshore — meaning crews might struggle to get to the pipe in an emergency, Biebel said.
Here’s what construction will look like
City officials have already inspected the pipe and — finding it in good condition despite its age — are finalizing the design for a construction project that will reinforce the pipe and nearby shoreline.
The project will provide shoreline protection from King Park all of the way to the treatment plant by regrading the shoreline, building a lot of stone revetments and building an access road for future maintenance.
“This project will not only provide protection of this critical asset in the sewer system, it will also protect the southside lake bank, which is quite steep as you start heading south,” Biebel said.
Construction crews will also raise the level of some manhole structures to protect them from future high water and wave action.
The project in its entirety is almost 8,000 feet long — more than a mile-and-a-half long — and will require a lot of material and heavy equipment, Biebel said, but he hopes most or all of the construction will be done next year. It depends on the schedule of the company that gets the bid this winter.
This project will lay the groundwork for future work to line the pipe when it becomes necessary in five or 10 years, Biebel said.
City will pay for the project using ARPA funds
Engineers estimated the project will cost about $10 million.
The city council allocated $9,950,000 in American Rescue Plan funds to pay for the project.
Without the ARPA funds, the city would have had to borrow money over a 20-year timeframe and increase ratepayers’ sewer bills by about $67.50 per year.
Instead, Biebel said sewer rates next year are expected to remain about the same as in 2021, Biebel.
This article originally appeared on Sheboygan Press: Sheboygan: Sewer line threatened by high Lake Michigan water levels