Manhole rehab and solving I&I issues took center stage Tuesday at the North American Society of Trenchless Technology’s No-Dig Show in Palm Springs, California.

Municipalities, engineers and consultants led discussions during the technical paper sessions, giving attendees an idea of the challenges utilities are facing and how they are working to solve them.

Julie McMullin, a consultant with Brown and Caldwell’s office in Milwaukee, Wisconsin, discussed an issue with laterals following a large rain event in 2010 in Menomonee Falls.

Menomonee Falls is part of the Milwaukee Metropolitan Sewerage District (MMSD), which is made up of over 3,000 miles of sewer lines and another 3,000 miles of private laterals that are tributary to the system.

“We had two really large events that happened in a period of two weeks in 2010 that caused widespread flooding and basement backups,” says McMullin. “From that event, MMSD decided they needed to do something about private property I&I. They needed to figure out how to reduce that.”

MMSD created a program that made funding available for seed money for municipalities to start looking at private property I&I. The municipalities were given funding based on the amount of service fees they paid into MMSD.

“While there are plenty of I&I sources on the public side from deteriorating manholes and poor sanitary storm sewers, we were looking mainly on the private side,” McMullin says. “In the Milwaukee metro area, the homeowners own the entire lateral from the house to the sanitary sewer main, so it is all considered private property.”

The first thing that Menomonee Falls did was develop policies and guidelines on how to use the funds. 

“It was a completely voluntary program only applying to single-family residential homes and some applications of multi-family housing if it’s three or fewer units,” McMullin says. “Also, nothing could be done without a written waiver form completed to give crews permission to enter the property.”

There was no cost to the homeowners or the village with the entire funding coming from MMSD’s program.

For investigations, crews first did flow monitoring, followed by dye-water testing of storm sewers or ditches. Then they televised the lateral.

Because of these inspections, Menomonee Falls found some areas that needed work. In the end, 47 laterals were lined using CIPP in order to reduce the private property I&I.

“We learned a lot on our project in Menomonee Falls,” says McMullin. “For example, we learned that locating I&I can be a challenging thing, especially if the groundwater level is high.”

Officials from the city of St. Helens, Oregon also discussed a multi-year I&I abatement program that was recently completed to reduce sanitary sewer overflows and treatment plant costs.

With a holistic approach to reduce I&I, St. Helens’ program rehabilitated 12 miles of sanitary sewer and installed 2 miles of storm sewer using open-cut and trenchless installation techniques.

In the final session of the education track focusing on I&I and manhole rehab, Bradley Marin of GHD Ltd. discussed the process by which GHD evaluated, designed and worked with a contractor to rehabilitate the Hespeler Truck Sanitary Sewer in Cambridge, Ontario — about 5,600 feet of vitrified clay pipe and 18 manholes varying in depth up to 15 feet.

COLE Publishing staff will be at the No-Dig Show throughout the week attending the sessions and will be in the exhibit hall (Booth 368). To reach us, email cory.dellenbach@colepublishing.com.