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Inflow and infiltration plagues Newport

The Newport and Metropolitan Council monitoring project would focus on four areas of the city that are using four different possible solutions to inflow and infiltration issues. Courtesy of the city of Newport

NEWPORT — After years of dealing with cracked and aging sewer infrastructure leading to increased rates and treatment of clean water, a Metropolitan Council grant could help ease Newport's severe inflow and infiltration problems.

Inflow and infiltration, or I/I, can be an effect from aging infrastructure, height of the Mississippi River, geography and soil around the pipes. When one of more of these or other factors affect a city's sewer line, rain water or other clean wastewater can get into the lines, causing clean water to have to be treated.

The city's sewer mains, installed in the early-1960s, are faced with two geographical obstacles, said City Administrator Deb Hill: the bedrock trenches the pipes were built into and the city's proximity to the Mississippi River.

The pipes sit in the rock, which then fills up during rain events and leaks into the sewer pipes at any crack in the system.

As major rain events batter the city more frequently, the system can overflow, leak and end up treating more and more clean water that doesn't need to be in the system, Public Works Superintendent Bruce Hanson said.

The severity of inflow has caused the system to overflow before, he said.

Hill said one beyond just overwhelming the system, inflow and infiltration also lead directly back to consumers with raised sewer rates every year as part of Met Council calculations.

"Communities that have significant I/I can have a major increase in sewer charges," said Marcus Bush with Met Council Environmental Services.

He said about two-thirds of metro communities deal with inflow and infiltration issues, and are in the Met Council I/I program.

The situation is so widespread a task force was formed in the early-2000s to find long-term solutions with inflow and infiltration, and its wastewater and environmental effects on the region.

When inflow and infiltration overflow a system, at times there's nowhere for it to go except the river or back up into homes, though these situations are rare.

Some cities in the metro have tried with lining their pipes or grouting to help seal the pipes, with the help of Met Council grants or advice. "Communities are working on tightening up their local systems ... and we're working on tightening up regional systems," Bush said.

About $19 million in grants have been awarded by the Met Council for inflow and infiltration projects. Newport has applied for all of these grants.

A chance at a solution

The Met Council is offering a one-time grant to launch an inflow and infiltration demonstration project.

"(It's) almost like a test project so they can gather some data, figure out which kinds of facilities, repair mechanisms, work the best so they can share that with the rest of the Metropolitan Council area and the rest of the state," said Lucas Jones from MSA, the city's consulting engineering firm.

If awarded the grant, Newport would receive a $500,000 matching grant that would launch a three-year study spanning the city from end to end.

Hill said they would likely bond for their share of the $1 million project.

In the past eight years, Newport has received about $250,000 from the Met Council for inflow and infiltration related repairs and projects.

The bigger amount could help make a bigger impact to the problem.

According to the Met Council, up to 80 percent of inflow and infiltration issues in a city can stem from the laterals — the pipes leading from the main to individual residences — on private property letting in extra water.

Part of the grant would specifically look at solving the lateral problem.

"The intent (of the grant) is to fix public and private infrastructure, but with an emphasis on removing private family or property construction," Jones said.

Across four separate test areas in the city, inflow and infiltration solutions will be implemented, including lining the sewer mains, adding grouting and sealing manhole covers.

Three of the four areas are directly along the river.

One option — complete replacement — won't be a feasible option under the grant because it's also the most costly option.

"Being cost effective is very important," Hill said. The city installed a few liners about eight years ago, but without lining the laterals, Hanson said it's hard to tell how much good the solution is doing.

"Laterals are exactly where the problems are," Hanson said.

Hanson said they've also tried some grouting before, with limited success.

Each time a road improvement or repaving project comes up in the city, Hanson said they can replace lines and laterals, but that means the current solutions the city can offer are largely small-scale.

The application will be submitted by Aug. 31.