Reveal’s work on New Zealand’s Riverlink project has validated the importance of an increased understanding of underground utilities for infrastructure projects. Sam Clive, Reveal’s Head of Delivery, takes Roads & Infrastructure inside this venture.
Before now, the infrastructure sector’s lack of knowledge regarding subsurface utilities was often a pain point.
Utility strikes have caused unforeseen delays and damage, so much so that typically 20 per cent of associated costs for infrastructure projects are set aside to cater for related issues with unforeseen subsurface conditions (per Reveal).
Sam Clive, Reveal’s Head of Delivery, says the company’s process helps to take the guesswork out of this potential headache.
“We do large-scale data conflation and investigations to create a three-dimensional model, which can be used right from the preliminary phase to the conceptual phase, so they can have the most accurate and complete information possible to design the project appropriately,” Clive says.
As experts in subsurface utility engineering, locating and surveying, Reveal utilises a variety of technologies to uncover the truth when it comes to the subsurface.
“We used the same concept for the Riverlink project,” Clive says.
“We’ve done some of the largest utility mapping projects on the planet. So we were able to give them a methodology for a very large 3D model and we were able to do so in a three-to-four-month timeframe.”
Riverlink is a collaborative project between the Greater Wellington Regional Council, Hutt City Council, Waka Kotahi New Zealand Transport Agency, iwi mana whenua Taranaki Whānui ki te Upoko o te Ika (Taranaki Whānui), Ngāti Toa Rangatira (Ngāti Toa), and the AECOM-Fletcher alliance.
The project aims to increase flood resiliency, support urban growth and provide better transport solutions throughout the region of Lower Hutt (just northeast of Wellington) by delivering a holistic package. This includes infrastructure development and transport improvements on a large scale.
“We were engaged by the project funders in early 2023 to create what they referred to as a base utility model that they could hand over to the design engineering alliance prior to them starting their works on the project,” Clive says.
“They wanted the engineers and contractors, when they came on board, to have some form of a model that they could use to start works immediately.”
The proposed utility engineering works required accurate subsurface data; therefore, the first step was to collate information that had already been gathered by utility owners.
“This approach has been refined by Reveal, and not many other firms do it this way,” Clive says. “The way that we like to approach the first step is to compile all existing records in one place to look at what we have.
“We go through the process of extracting and transforming that information into a consistent database that digitises and geo-references all the PDF plans. From there we can go through a phase of verifying and correcting the data, because some of these records can be inaccurate, whether it be the wrong location or depth.”
Clive says the next step is known as ‘aerial picking’, a process of evaluating aerial imagery of objects such as chamber lids, cabinets, valve covers and more. This information is then overlayed with existing records to paint a more accurate picture.
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The third phase of the process features the use of ground-penetrating radar. This technology uses radar pulses to create an accurate image of subsurface utilities and “unknowns”.
This technology is towed behind a vehicle at night, thus minimising impacts on local businesses and the community – prerequisites that were outlined in the proposal phase.
“Minimising disruptions is really a key driver of what we do. People want to minimise the number of disruptions, which ultimately ties back to our service. Unknown subsurface utilities and consequently, utility strikes can create significant losses,” Clive says.
“With the technologies that we’re adopting as a firm, we try and be as non-invasive as possible. Rather than leaving permanent markings, we capture and digitise our records. That way we don’t have to do rework and that extends to our clients. They won’t need to do rework and create more disruptions for traffic in their projects for example.”
In order to also cater for both budget and time constraints, both Reveal and the project stakeholders went for a broad stroke approach. Instead of concentrating on a specific section, this model provided a wider overview for works on Te Awa Kairangi ki Tai.
“Using our software and the initial model that we created, the idea is that [Waka Kotahi] will be able to do more investigations over time and improve it as part of a risk-based approach,” Clive says.
“So instead of throwing every tool out for every square metre of the project, we can create a base model for the whole project. Then they can understand where the risk lies.”
Clive stresses that this is an ongoing process, one that Reveal is actively engaged in with project stakeholders as the project progresses.
“Any changes that we make go back to the asset owners so that these records can be updated,” Clive says. “The model that we create becomes a skeleton and a framework for these changes to occur.”
Clive adds that the model used for this project can cater for infrastructure projects of varying scope and scale.
“It fits within whichever [project] phase that you’re in. Whatever budget you’ve got, or risk approach you take, there’s something for everyone,” Clive says.
He says the Riverlink is a “great example” of this collaborative process.
“It shows that they’re progressive. They’ve been incredibly supportive of our ability to test the status quo; to do something innovative. They’ve been willing to invest to solve what could potentially become an issue,” Clive says.
This article was originally published in the September edition of our magazine. To read the magazine, click here.