Crowded underground

As Ontario’s transportation, utility, and municipal infrastructure networks expand, the challenge below ground extends beyond finding room for new construction. Project teams must first understand and navigate an increasingly dense network of existing assets, aging infrastructure, and difficult ground conditions.

Corina Moore, executive vice-president of transportation and infrastructure at WSP Canada, says growth, infrastructure renewal, and new utility demands are being compressed into corridors that were never designed to accommodate that density. “Modern infrastructure demands have made the underground environment more crowded, layered, and interconnected,” she said. That density can constrain infrastructure delivery, particularly in growing urban areas. Unknown utility locations, incomplete maintenance records, and aging assets discovered during construction can complicate designs, disrupt schedules, and increase costs.

The congestion is particularly acute in Toronto, says Mitch Panciuk, president and CEO of Ontario Dig Authority. “You just have to look at any major construction project in the downtown core,” he said. “There is infrastructure criss-crossing and going every which way, and it’s at a depth level that is unbelievable.”

A really good geotechnical investigation report is critical, and I can’t emphasize that enough. We see so many projects with reports that … just aren’t adequate.

Mark Montgomery, Keller North America

Existing infrastructure is only part of the challenge. Mark Montgomery, director of infrastructure for Keller North America, says development is also being pushed onto sites with more difficult ground conditions. “The good ground has been built on for the most part. Newer structures are typically being built deeper and on trickier ground,” he said. Foundation elements may now extend as much as 300 feet below ground, requiring solutions that Montgomery says have become more sophisticated and costly.

When existing utilities conflict with a project, Montgomery’s preferred solution is to relocate them before foundation construction begins. That option, however, is becoming more difficult as utility owners increasingly resist relocation. The age and condition of those assets can compound the difficulty. Montgomery points to brick sewers dating to the early 1900s as one example of the fragile infrastructure contractors may have to work around.

Better underground mapping

As underground networks become more crowded, the need for accurate, accessible asset information is growing with them. According to Panciuk, one of the biggest obstacles is that existing records remain fragmented across different owners, formats, and data systems.

“I think the most important thing that’s changed in the last 10 years is that the environment [has become] a lot more complicated. There’s more infrastructure and there’s more excavation, and those two factors are really showing that we need to have better records,” he said. “In this really fragmented environment of mapping information, the challenge is being able to pull it all together so that we have accurate information.”

Ontario Dig Authority has proposed a unified infrastructure mapping strategy to the provincial government. The proposed system would consolidate different formats and data models into a single authoritative base map accessible to infrastructure owners, planners, designers, and excavators.

You just have to look at any major construction project in the downtown core. There is infrastructure criss-crossing and going every which way, and it’s at a depth level that is unbelievable.

Mitch Panciuk, Ontario Dig Authority

The UK began developing its National Underground Asset Register in 2018. Panciuk says approximately 80 per cent of the country’s underground assets have now been mapped, and participation is expected to become mandatory for buried-infrastructure owners. According to Panciuk, the system has reduced the average time required to locate asset information from about six days to six seconds. The value extends beyond excavation. Reliable underground data allows architects, engineers, and municipal planners to identify conflicts and constraints while future infrastructure is still being planned.

Ontario Dig Authority has proposed rolling out a similar program, the Ontario Underground Infrastructure Mapping Strategy, over six years at an estimated cost of $70 million. A cost-benefit analysis commissioned for the proposal estimated more than $1.3 billion in economic benefits over 10 years, through damage avoidance, improved worker and public safety, better data acquisition, and more efficient excavation.

Moore says Ontario project owners are investing in digital asset records, but better technology must be supported by stronger data governance and more consistent processes. “We have to put that data governance in place, so that we have earlier utility investigations and more consistent utility co-ordination processes,” said Moore.

Understanding subsurface conditions

Better information, however, depends not only on accurate asset records but also on a thorough understanding of subsurface conditions before design and construction begin. Montgomery says a thorough geotechnical investigation early in a project can reduce uncertainty, prevent avoidable problems, and ultimately save money. He sees growing reluctance among some project owners, particularly in the private sector, to invest upfront in comprehensive geotechnical investigations. Instead, many rely on reports that meet basic requirements but lack the interpretation and analysis needed to guide major design decisions.

“A really good geotechnical investigation report is critical, and I can’t emphasize that enough,” said Montgomery. “We see so many projects with reports that, at least in our opinion, just aren’t adequate.” Montgomery points to private developers who commission only a basic, “tick the box” geotechnical report while financing is still being assembled. His advice: “If you have to do that to get your project moving, build in a second round of properly done geotechnical investigations.”

I think we have better tools and we have better modeling, but the issue is shifting from whether space exists underground to whether we can understand and optimize and manage what is actually there.

Corina Moore, WSP Canada

Better information is also influencing how underground structures themselves are designed. One example is the industry’s response to Toronto regulations aimed at reducing flooding risks associated with aging sewer systems that combine household wastewater and stormwater runoff.

Montgomery says the new regulatory environment is forcing project owners to rethink how underground structures are designed and waterproofed. One result has been a rise in below-grade bathtub-type foundations that restrict groundwater flow, requiring engineers to account more carefully for groundwater movement throughout the life of the structure.

Technological tools

Infrastructure owners and excavators are increasingly relying on digital tools to better understand and manage underground complexity. According to Panciuk, digital platforms allow project teams to process large volumes of underground asset information, identify patterns, and improve planning efficiency.

Moore says underground mapping has advanced “leaps and bounds” over the past decade. Technologies such as ground penetrating radar, LiDAR, Building Information Modeling, and digital twins are helping the industry move from reactive problem-solving to predictive planning through richer, more integrated data, giving project teams a clearer picture of underground conditions before construction begins.

“It allows all the players, whether it’s the designer, the contractor, or the client, to see exactly what’s in the ground, and builds a clearer, more reliable picture of the underground conditions before the construction begins,” she said. Moore says better technology has changed how project teams approach underground complexity, shifting the focus from reacting to conflicts during construction to understanding and managing them much earlier in the project lifecycle. “We have better tools and we have better modeling, but the issue is shifting from whether space exists underground to whether we can understand and optimize and manage what is actually there,” she said.

A really good geotechnical investigation report is critical, and I can’t emphasize that enough. We see so many projects with reports that … just aren’t adequate.

Mark Montgomery,
Keller North America

That shift is changing when underground challenges are addressed.

“We are just layering onto all these things at the same time, which creates more congestion and confusion,” she said. “Because we have this level of complexity, it’s moving from a construction issue to a front-end planning and design issue. The most successful programs recognize that utility relocation and the co-ordination of stakeholders are not secondary activities. They are actually core delivery strategies that influence the project scope later. WSP is involved in more than 60 of the top 100 major infrastructure projects in Canada, and what we see is that increasingly they’re being structured around this early utility investigation.”

Moore believes that extensive, up-to-date underground utility data should be treated as a strategic asset rather than a project constraint. She says collaborative procurement models allow project owners, designers, engineers, and contractors to work from the same information earlier in the process, improving decision-making before construction begins.

“When we deem it a strategic asset, it is part of the decision-making from day one. It’s not something that pops up and suddenly becomes a risk affecting scheduling and constructability and therefore is an added cost,” she said. “You have to invest in the planning beforehand so that you can reduce that risk. It’s all about converting uncertainty into actionable information early on. That way, we know exactly what it’s going to take to construct what we design [and] we can all make improved decisions earlier on in the process,” she said.

As Ontario undertakes an unprecedented wave of transportation and infrastructure investment, the ability to understand what already exists below ground may become just as important as the infrastructure being built above it.