Project Spotlight: Refresh Woolloomooloo
Heritage protected infrastructure, confined spaces and thousands of stakeholders in one of Australia’s oldest and most culturally sensitive precincts.
That was the challenge Diona faced when they took on the technically and culturally sensitive task of retrofitting4.6 kilometres of wastewater pipes in Woolloomooloo and Darlinghurst.
Such was the difficulty of the project that it was many years in the planning, as local authority Sydney Water completed as many surrounding works as possible before tackling the final section in its bid to bring inner Sydney’s convict era drainage system into the 21st century.s
Fortunately, the team from Diona assigned to the massive and technically challenging task had the persistence, courage and outstanding problem-solving skills to not only be four months ahead of schedule on project works, but also work closely with the local community to keep all stakeholders informed and disruption as minimal as possible within a highly dense residential and commercial region of Sydney.
Senior Project Manager Tommy Kelly, recently shared some of the highlights of this project which he considered unique in its complexity.
“It was very unique in comparison to some of the other wastewater projects we have done,” he said. “It was many years in the planning by Sydney Water as it was always looked upon as a very technically challenging job. A lot of people in Sydney Water were quite passionate about the project as they had worked tirelessly over a long period of time to plan it and get it over the line.”
At the heart of the project was a convict-built brick pipe called an oviform. This six-foot-high, four-foot-wide oval brick pipe had served the inner-city precinct as a combined storm and wastewater drain since the 1820s. Two centuries later,
it continued to perform its task admirably. However, the advent of the modern sewerage system, and a greatly increased population, posed a complication.
“Originally stormwater went into the oviform,” Mr Kelly said. “But now you have waste from toilets coming out of houses and into that same pipe. Back in the day, that was the same for every city in the world. That’s just how they did it. Many areas in Sydneyhad been separated, but given the complexities of the works required for this area, Sydney Water were committed to getting it right and so it took the longest to plan.”
The difficulty associated with this particular region occurred during times of heavy rain, which resulted in the sewage and stormwater overflowing into nearby Woolloomooloo Bay.
The importance of separating the wastewater from stormwater was obvious to all concerned – the challenge was how to achieve it. Mr Kelly said there were several large challenges
to be overcome: a busy inner-city precinct, work in restricted areas, busy roads and 35,000 stakeholders (including businesses, schools and residents).
The fact that the area is a busy CBD precinct, with heritage buildings built at very close quarters (as was the norm in the19th century) were significant complications to consider when planning the project.
“Some of the areas we were in very busy roads with very busy local businesses – so the impact on the community was quite high,” Mr Kelly said. “The challenge was to get the job done efficiently with the least impact on the local community. But given the volume of the work, it required big plant and machinery and challenging ground conditions.
“There were two extremes that we were working with. We either had really hard rock, which we dealt with using large rock saws and big equipment, or we had ground that was water charged with very low stability. So, there were different technologies and equipment we had to use depending on where we were. And then, in most instances, the equipment you’d use in normal circumstances, couldn’t be used because of the confined space or the need to ensure at least one traffic lane remains open during the work.
For instance, we might have a20-tonne excavator where we might really need a 30 tonne, but we couldn’t fit that, so we had to try to make do with what we could use. For those reasons, it was very challenging. All the gas, electricity and communications were in the ground already, but the sewer is five to 10 times the depth of the other services, so we had to support all those assets, make sure we didn’t damage anything and pass under them without affecting their operation. Usually, if we’re doing a new estate or a new development, the first thing we put in is the sewer because it’s the deepest, then you put everything else in on top of that.”
Which begs the obvious question: How?
“One word, communication,” Mr Kelly said. “Open communication along with careful planning and teamwork were the most important elements of this project. We had a really strong team and all of our crews on site were very experienced and there was great comradery between everyone on site. Everyone that was here was a team player. They wanted to help each other and the community going above and beyond to achieve a good result.”
The project was very successful. “That’s all down to the planning and the hard work of everybody involved.” Mr Kelly said. “We had daily meetings, weekly meetings, monthly updates – we monitored everything closely, because if one thing slipped, it could have had a really bad knock-on effect.
“We always had a Plan B because there were a lot of unknowns. Much of the area is heritage listed and there were multiple underground services that nobody knew were there. So, when our teams were excavating they would often discover an asset our design hasn’t considered because it wasn’t on any drawings due to how old it was.”
Managing Heritage Listed Discoveries
“At the start of the project we were discovering a lot of heritage items,” Mr Kelly said. “Anything sandstone, even the sandstone kerbs you’d see on the street, are all heritage. To remove
items like this, there is a certain process you must follow to ensure we were protecting their heritage which involves gaining approval from an archaeologist, or the Heritage Council.”
However, with careful planning the Diona project team minimised disruptions caused by the unforeseeable. “We came up with a protocol that identified different scenarios where it was acceptable to remove the heritage items without referring to the Heritage Council every time,” Mr Kelly said. “Having to go to the Heritage Council every time we came across heritage items such as glass bottles would have caused delays and additional costs for the project. So, we worked collaboratively with them to try to reduce those costs. At one stage, we were coming across heritage every second day.”
Some of those items, included convict-made bricks and glass bottles. “We uncovered many significant artefacts, including dinner plates, bottles and even old privies (outdoor toilets)” Mr Kelly said. “They were really impressive. I don’t know how they didn’t break when we were excavating around them.”
Then there is the built heritage, which in most cases remains people’s homes and businesses. “When we were working close to them we were very careful,” Mr Kelly said. “We would set up vibration monitors and alter our construction methods. Those old buildings are very prone to damage and cracks, so we had to put in measures to make sure we didn’t cause damage.”
Working with the Community
Although he had worked on similar projects internationally, Mr Kelly said it was one of the most challenging projects he had worked on. “One of our biggest challenges was keeping so many stakeholders happy, because in order to achieve the end result, which is a constructed separated wastewater and sewer system, we were going to impact people,” he said. “You just need to manage that and mitigate it as much as possible. But at the end of the day, it had to be done – we were going to have excavators out the front of people’s houses, we were going to have truck movements, we were going to be breaking rock. It was a matter of managing all of this and I think we did very well. Our client, Sydney Water is extremely happy, and the overwhelming majority of stakeholders were happy as well.
“If we were installing a new wastewater or sewer pipeline in a greenfield site through a paddock, it’s a walk in the park. When you have to think of pedestrians, traffic, noise and vibrations, updating the community, keeping everyone informed, it becomes very complex. So, you have to pre-empt issues, lookahead and plan. The key to a successful project like this is having a good team. One where everybody pulls their weight and works together.”
Examples of the planning involved to lessen the impact on the community, involved a nearby school and a newborn baby.
“Forbes Street was an area of extremely high strength rock,”Mr Kelly said. “You have to use breakers and big saws to cut the rock, which creates a lot of noise, vibration and dust. There’s a private girls’ school just off Forbes Street and, of course everyone was very nervous when we said we were going to start there.”
Part of the solution was to start in the school holidays. “We found that was a good move because it got the whole crew into a rhythm when we started to get everything set up,” Mr Kelly said. “We were able to make sure that when the kids came back to school after their holiday we had everything running like clockwork. But the exams were on when the students came back, so everybody was concerned because we didn’t want the students affected.
“We put numerous provisions in place to reduce the noise. We brought in specialist equipment and used multiple acoustic barriers to contain the noise. We also staggered breaks so that they coincided with exams, and carried out maintenance and other inaudible works.
But communication was, as in every other aspect of the project, the key. “We ensured there was ongoing consultation with the school,” he said. “We had a weekly meeting with the school to give them an update on progress, tell them our plans and ask them how they were going or if there were any issues.”
“And to everyone’s surprise, we actually managed to keep operating in that street and get the work done. We received exceptional compliments from the school and when SydneyWater’s senior management visited the site, the school’s management spoke to them and expressed their appreciation for everything we’d done to work with them.”
Another achievement on the same street involved just one child – a very small one. “There was a newborn baby in one
of the buildings. So, we made contact with the parents of the baby and we had an arrangement that the lady would send a text to our supervisor when the baby was going for a nap and we’d stop our work for a little while. Then she’d text back to our supervisor to say ‘he’s awake now, good to go again, off you go’. At Diona, if we can plausibly accommodate the needs of a single person – in this case, a newborn, we will.” The outcome was that area of the project was finished four months ahead of schedule.
Mr Kelly’s praise for the entire team was effusive. “You couldn’t ask for a better team, you really couldn’t,” he said. “We’ve really had a good experience on this site. And what we had
in the site office as well was unique. We invited Sydney Waterin to work with us. So, their team actually sat in with us and
we could walk over and bounce ideas off them and ask a few questions. We were always there for them, and if they had any issues or queries we worked collaboratively together.
“When I look back on it, it’s like any project, there’s things where I would say next time I would do it a little bit differently. Overall though, it’s been a great experience for anyone who’s worked here, from the crews on the site, traffic controllers, sub-contractors, the management team, the communications team, the safety team – everyone has learned valuable lessons.
“It’s great to have done what we have, to look back and say everyone doubted we could do it. But we all got together to come up with a good plan, we stuck to the plan, improved it as we went, communicated well with everyone, did everything we could to work in with the community. I think we’ll all walk away having achieved a good outcome, a happy client, happy community. It’s a good feeling for everyone to have achieved that.”
For Mr Kelly, it’s the positive impact this work will have on the environment and community that makes projects like this rewarding.
The new infrastructure we have installed will remove any waste overflow into the Woolloomooloo Bay which will benefit the environment and local community for generations to come – with a little luck, it will be another 200 years before it will need to be upgraded again. For me, this brings a lot of pride, to know that our team played a small part in creating a more sustainable city for future generations – it’s our legacy and that’s why I love what I do,” he said.