MARQUETTE — Problems caused by spring runoff and recent heavy rainfall in the city of Ishpeming may have been much worse if not for an eagle-eyed Ishpeming Department of Public Works employee who saw “swirling” in Lake Bacon on Sunday.

“‘Hawkeye’ John Harnet looked and saw it in the water,” City Manager Mark Slown said. “He saved the day, and a bigger problem was narrowly averted.”

Despite efforts by the city to remain proactive, Slown said the water from Lake Bacon had begun to flood into the Park Street Lift Station, forcing the city to discharge flood water combined with diluted sewage into the Carp River for roughly 18 hours.

He said if that volume of stormwater had continued to infiltrate the city sewer system it could have had serious consequences, namely sewer backups in residents’ homes.

“A few houses around the school have had backups, but we have been pumping as soon as we knew the rain was falling,” Slown said in a phone interview Tuesday. “In this case, we had to berm the area with large sand bags. A. Lindberg and Sons helped with that. They brought sand bags that can only be lifted by a crane because what we had was not capable of holding the water back.”

The city notified the Michigan Department of Environment, Great Lakes and Energy, the Marquette County Health Department and The Mining Journal as required by law, District Supervisor of the Marquette EGLE Water Resources Division Jay Parent said in a Wednesday email.

“The city of Ishpeming had to pump out diluted sewage from their collection system to protect homes from basement flooding,” Parent said. “The event was due to high groundwater and excessive rain that infiltrated into the collection pipes. The pumping continued for about 18 hours and was discharged to the city stormwater system, which discharges to Partridge Creek and ultimately Carp Creek. While unfortunate, the city needs to first protect public health by preventing sewage backups into basements.”

The city has been working with GEI Consultants to inspect, televise and map its sewer infrastructure, Slown said. That work is funded, in part, by a $1.3 million EGLE Stormwater Asset Management and Wastewater Grant awarded in 2016.

In addition, GEI and the city have been metering and monitoring the city’s sewer systems for the past year, GEI Senior Project Engineer Mark Stoor said.

Meters that were placed in the sanitary sewer system during two large storm events in the last year recorded peaks in flow, Stoor said. Additional meters have been placed farther down the system to identify further problems with stormwater infiltration.

“It is common for municipalities to have some level of infiltration of rainwater (often referred to as “clear water“) into their sanitary sewers through cracks in pipes, manholes and basement stormwater sump pumps illegally connected to sanitary service laterals,” Stoor said. “When the groundwater is high, as it is right now, and a heavy rain or snowmelt event is added to it, this exacerbates the issue. When this happens, the clear water infiltrates into the sanitary and can result in sewer backups on some occasions, as well as additional costs of treating extra water.”

Parent said the city is not the only Upper Peninsula community to encounter the infiltration of stormwater into its sanitary sewer.

“With the amount of snowfall and rain the area has received over the last few seasons there have been a number of U.P. communities that have experienced hydraulic issues, both in their collection systems and at treatment facilities,” Parent said. “The spring (six) years ago resulted in similar conditions.”

Stoor said once all the data has been collected, GEI will provide Ishpeming city officials with a report that can be used to plan future repairs of the system.

Lisa Bowers can be reached at 906-228-2500, ext. 242. Her email address is lbowers@miningjournal.net.