The district is seeking both conditional use and coastal development permits for the tunnel repair, which includes realigning 740 feet of the tunnel under bluffs at Three Arch Bay.
Residents near a proposed 15,000-square-foot construction staging area at Fourth Avenue and South Coast Highway are concerned about noise, dust and traffic that could result from vehicles going in and out of the district-owned property.
Carl Goodwin, who lives on Florence Avenue near the proposed staging area, represented several residents at Wednesday's meeting.
"We heartily support the project," Goodwin told planning commissioners. "Our interest is maintaining a reasonable quality of life for the life of the project."
Goodwin's concerns center on noise, including trucks' back-up "beeps," and dust. He asked if construction vehicles could stay off a portion of Virginia Way south of Third Avenue.
The project is expected to last five years and cost about $80 million, said Joe McDivitt, the district's interim general manager.
One million gallons of sewage travels through a pipeline each day within the two-mile-long tunnel, originally built in 1954, a district staff report said.
The tunnel, which is 6 feet wide by 6 feet high, runs parallel to Coast Highway and is primarily located beneath privately owned oceanfront properties from Three Arch Bay north to Aliso Beach Park, the report said.
The tunnel is deteriorating and repairs are needed to prevent it and the sewer pipe from failing, according to the report. It added that an upgrade would make working conditions for district employees and contractors safer.