SOUTH PORTLAND — Base construction and sewer separation necessary for the planned Mill Creek Transit Hub are slated to begin in less than two weeks.

Councilors on Monday approved a $560,000 bid from Maietta Industries of Scarborough to do the work in the Knightville-Mill Creek area.

The work is part of a multi-phased plan for several city departments and utilities to combine efforts to reduce how often sidewalks and streets must be ripped up.

The first phase, expected to begin Aug. 15 and be complete by Nov. 15, includes reconstruction of the City Hall parking lot; reconstruction of curbs and sidewalk on the east side of Ocean Street between Hinckley Drive and the end of the City Hall parking lot; new pavement, sidewalks and driveway aprons on both sides of Ocean street south of Hinckley Drive to Broadway; and sewer separation on Thomas Street and a small section of Ocean Street at the intersection with Thomas.

City Manager Jim Gailey said he was unsure whether any major traffic routes would be completely blocked.

“Traffic will be delayed somewhat, but we haven’t received the traffic plan from the contractor as of yet,” Gailey said. “I don’t see us closing off Ocean Street, but we may close off Thomas Street.”

Sewer separation is dividing sewage and storm-water runoff systems to prevent the overflow that can lead to sewage being dumped into Casco Bay or the Fore River through a combined sewer overflow. Before undertaking sewer separation projects, South Portland had 28 such overflows. That number has since dropped to five.

The work involves the Public Works Department, Transportation Department and Water Resource Protection Department. The directors of each department decided to come together for the project in order to reduce duplication of effort.

“It made sense to do the sewer separation now so that we wouldn’t have to tear everything up twice,” said Brad Weeks, city engineer with Water Resource Protection.

There are dozens of so-called combined catch basins in the area that empty into the sewer system. If more than 2 inches of rain fall in a short period of time, Weeks said the system overflows into Casco Bay. While there is no CSO in Knightville, the system is attached to a trunk line that carries the overflow to one near the U.S. Coast Guard Station in Ferry Village.

When all phases of the transit hub plan are complete, the Water Resource Protection Department will have removed 43 combined catch basins, Weeks said.

The work planned for the parking lot behind City Hall includes paving the unpaved portion and increasing permeable cover, said Dan Riley, senior project manager at Sebago Technics, who will oversee the project for the city.

That means installing features like concrete pavers with sand joints, and depressed landscape areas to filter out storm water before it enters the new, separated system. The lot will have 43 striped parking spaces, which might mean fewer cars will fit than in the unpaved, unstriped lot next to Ocean Street.

Riley said the parking lot improvements prepare the site for the construction of the planned Mill Creek Transit Hub, one of the future phases of the project. He said the reconstruction makes space for the transit functions and improves flexibility in the lot’s usage.

“This improves the function of the entire site,” Riley said. “When you take that parking area out for the transit hub, it reorients the rest of the parking lot. And it allows the transit and other municipal functions to happen at the same time.”

Eventually, the corner of Thomas and Ocean streets will host a central exchange building for the city’s buses. The closed building will feature seats for riders to wait for their buses.

City councilors on Monday also:

Knightville Phase i