The Greenbelt Trunkline Sewer Replacement Project is now in its final stages, with work set to be complete by mid-August. Officials say they just need to repave part of the trail. Krysteana Scribner / The Forecaster

SOUTH PORTLAND — Substantial progress has been made on a sewer project along the Greenbelt Walkway that has restricted access to part of the popular trail for most of the summer.

While the contract date for the $1.5 million Greenbelt Trunkline Sewer Replacement initiative allows for construction into October, officials now say the project should be completed by mid-August.

Construction inspector Mike Kane of Sebago Technics, who contracted with the city for the project, said there were initially conflicting estimates about when the project would be done because of uncertainty about weather and unforeseen technical issues.

A barricade on the trail at its intersection with Cottage Road promised completion by July 31, while letters sent to residents May 29 said the work may take until the end of August.

On July 30, however, Kane said no problems have appeared and work has been quite smooth.

“The weather has been decent, and there weren’t too many rainy days, so it certainly has helped,” he said.

The project, which began June 17, will reduce the size and frequency of combined sewer overflows and is a requirement of the city’s stormwater permit.

It involves replacing the sewer trunkline from the intersection of Mussey Street, down 3rd Street and on the Greenbelt toward Broadway, and required closing the trail between Cottage Road and Mussey Street. The 5.6-mile trail extends from the Wainwright Athletic complex near the Scarborough town line to Bug Light Park, and is popular with runners, walkers and bicycle riders.

Kane said workers finished connecting all 800 feet of sewer pipe along the trail on July 30 and also installed the final manhole.

“The bulk of the work has been completed, now we just need the grass to grow in,” he said. “We’ll also need to pave a stretch of the Greenbelt. My guess is, the paving will begin next week or the week after.”

Contractor working hours are typically weekdays, 7 a.m.-7 p.m., with limited exceptions. During those hours, residents are asked to use the sidewalk on Broadway instead of the trail along the Mill Cove shoreline.

In an interview June 19, city civil/transportation engineer Justin Gove said combined sewer systems are designed to collect rainwater runoff, sanitary sewage and wastewater in the same pipe. While the system typically transports all wastewater to the water treatment plant, heavy rainfall or snowmelt can cause overflow that discharges into the Fore River and Casco Bay.

This overflow, Gove said, is mainly stormwater, but there is still some sewage in the mix. Combined systems were built prior to the implementation of the Clean Water Act of 1972, so the concrete pipe deteriorated at a faster rate and is being replaced with a plastic pipe to ensure longevity.

According to Kane, the 24-inch pipe installed in the 1970s is too small in diameter to handle the water flowing through at peak times. He said the pipe, which was originally intended to serve a smaller population, can no longer keep up with the demand and volume, which was a driving factor in the decision to replace it with a 36-inch pipe.

The project was first discussed in a facilities plan in 2011 and put out to bid in May after the preliminary design was completed last year. The only bidder was Grondin Corp. of Windham.

City Water Resource Protection Director Patrick Cloutier said June 18 that almost $1.2 million of the project is funded through the sewer user fund in the city’s capital improvements budget, while the rest of the cost is covered by tax increment financing funds.

The project is part of a larger ongoing series of work being done to address combined sewage overflows in the city.

In 1986, South Portland had 28 CSO locations and discharged more than 500 million gallons of water into the Fore River and Casco Bay every year.

As of 2018, there were only four CSO locations that discharge a combined 3.5 million gallons a year.

Over 33 years the city has spent more than $45 million addressing the issue.