What's happening underneath the manhole covers? The city wants to find out

An Elgin, Illinois, company will be on Springfield's northeast side this week to evaluate the condition of the sanitary and storm sewer manholes.

The work follows up an administrative order the U.S. Environmental Protection Agency issued against the city in 2013 after documenting sanitary sewer overflows.

The overflows, or SSOs, violate the federal Clean Water Act.

The process going on this week will not affect operation of sewers and there will be no disruption of service at any point, according to a news release from the city.

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Tim Sumner, a project engineer and manager for Crawford, Murphy & Tilly, Inc., said Duke's Root Control Inc., will use a 360-degree camera to find out what kinds of defects are going on inside the manholes.

CMT has been contracted by the city to manage the investigation. CMT first got involved in 2015 to help prepare a plan in answer to the U.S. EPA's administrative order.

The work will be going on in a pilot area that includes Sangamon Avenue on the north, 22nd Street on the east, Ridgely Avenue on the south and 19th Street on the west.

"We're going to do some intense evaluation of the entire system in this pilot area and see what works and doesn't work so we can apply those lessons to the rest of the (larger northeast study area)," Sumner said.

According to a public presentation Sumner made last month at St. Aloysius School, the pilot area includes some 424 parcels.

SSOs happen when there's so much water in the sanitary sewer system that it gets overloaded, Sumner explained. The hydraulic pressure build-up pops the lids off manhole covers in some situations and can back up sewage into residents' basements, he added.

The northeast part of the city has a history of sewer surcharge and basement backups, Sumner noted in his presentation.

To alleviate the problem of basement backups, the city's Office of Public Works used to pump out of the manholes during heavy rainfall events, sending that water to a tributary of Spring Creek.

That practice is no longer allowed, Sumner said.

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The sanitary sewer systems are aging, Sumner admitted, with most 50-plus years old, though some are approaching 70 to 75 years.

There are other issues with the sewer system: potential cracks in the pipe, broken connections and connections from residents' sump pumps, Sumner allowed.

CMT crews and other companies, Sumner said, have been out in the area.

CMT is inspecting private properties for downspouts and area drains connected to sanitary sewers, he said.

The city's sewer division is cleaning and inspecting sanitary and storm sewers. Midwest Engineering and Testing is installing four monitoring wells to measure groundwater levels located between curbs and edges of sidewalks.

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Petersburg Plumbing & Excavating is performing smoke tests and dye water tests on sewers, as well as performing inspections on residences with basements, while Hoerr Construction is inspecting sewer laterals.

Data collected from the investigation, Sumner said, will help predict what combination of public and private propertycorrections will be sufficient to eliminate SSOs. It also will determine if repair and rehabilitation of defects anddisconnection of clear water sources used in the pilot area can be applied to the rest of the study area.

Work is scheduled to continue into mid-2023. Another public meeting will be held next summer before CMT submits its pilot area investigation report to the U.S. EPA in October 2023.

Contact Steven Spearie: 217-622-1788, sspearie@sj-r.com, twitter.com/@StevenSpearie.