This work is extremely dangerous and complicated. The sewer lines are large enough for a person to walk through, so to do the repairs, there was significant coordination to bypass operations so the flow would go above ground and back down into another manhole. Crews first jackhammer, then sandblast, and finally repair structural parts of the manholes, all in this dangerous environment. The sewage is “dosed” upstream with chlorine powder to reduce odors, and protects workers in the pipe. Workers wear full gear respirators and protective equipment.

YPMO was involved in the design/assessment phase, so when the project went into construction, they had construction notifications ready to go. They had a strong sense of the project areas, had done due diligence, and created maps ahead of time.

YPMO has also worked with other engineering and construction firms on other parts of the SRO Manhole Rehabilitation project. “There are engineering companies working with the City on all this infrastructure,” says Anne Thompson, president. “We have been the common thread for all the design and construction phases for public outreach.”

The work involved identifying manholes along the route, and then scheduling crews to accommodate business needs and schedules. Knowing the alignment and number of manholes, the YPMO team created construction flyers for each one-mile segment.

“This went from Tempe to 91^st Avenue, so the contractor had to skip, hunt and peck for where they would have their crews work,” says Thompson. “In one location, there was a manhole in the loop 202 right-of-way that ADOT was just opening, so they didn’t want the crews in their new roadway. Crews were moving around a lot; it wasn’t a straight or linear project. There was some overlap at 51^st and 59^th Avenues and some residents and businesses got more than one notice.”

The work proceeded along Loop 202 in Tempe. When the work started, YPMO anticipated working closely with Tempe’s waterfront stakeholders. With the extreme danger of working in the large diameter pipes, the team was worried about working along Tempe Town Lake, and focused on odor mitigation and safety.

The project also included Sky Harbor International Airport and the Rental Car Facility, which required significant coordination with the contractor. Construction crews roped off stalls to allow adequate space for manhole repair, and sometimes they had to wait for the traveler to return to get access. Working at the airport was challenging prior to the COVID-19 pandemic. When few people were travelling, the construction teams had easier access for manhole repairs in parking garages.

There were also golf courses along the route, which required coordination and communication to minimize impacts. For example, YPMO learned when courses were in lower use seasons, so the construction impact would be minimal on their operations.

This project was originally intended to be 12 months, and extended to more than 18 due to COVID-19 quarantines and public concern regarding COVID-19 existing in the sewer water. The water was tested, and it was determined that their concerns were false.