WC145 NovDec 2025 - Magazine - Page 25
“It’sagenerationalprojectthat’sgoingtohavehugeimpacts.Short-term,
obviously,there’sconstructionimpacts,butlong-termit’sgoingtohave
hugebene昀椀tsfortheregion.”
install water main along this first stretch. News reports
at the time said this was $22 million more than the engineer’s initial estimate, largely due to significant price
escalations in the construction industry and a saturated
construction market. A report to Metro Vancouver’s
Water Committee that year attributed the cost increase
to pent-up demand for infrastructure spending coupled
with ongoing supply chain issues impacting material
availability, price stability, high energy prices, labour
shortages, and rising interest rates.
Metro Vancouver dipped into its project contingency fund to make up the $22-million shortfall, but the
project falls within the growth category so the overall
budget comes from development cost charges. “The idea
is basically that growth pays for growth,” Cheng says.
“The municipalities collect those fees from new developments in the region, and those fees are transferred to
Metro Vancouver to fund these growth projects.” Another significant source of project funding comes from bulk
water sales to member municipalities. “Those also fund
our capital projects,” Cheng says. “It’s a combination of
development cost charges and user fees.”
While cost containment is always an underlying
priority with large infrastructure projects, the Coquitlam project team also has its eye on meeting the
many technical and practical challenges that come with
installing underground pipes in immediate proximity
to roadways. With the new pipe wider than a vehicular
travel lane, contractors installed an extensive shoring
system along that first stretch, from Robson to Guildford Way, prior to excavating their trench. “Typically,
contractors do the excavation and then put in shoring
cages at key points where they need to get into the
trench and access the pipe,” Cheng says. “But this was
a bit different because we had to install the shoring
system before we started excavating. That way we could
control the width of the excavation so that it didn’t
slough in and cause it to widen and impact even more
traffic.” Shoring materials include metal plates slotted
in between H-piles, all held in place with a combination of the existing ground and concrete to essentially
ensure protections are in place when crews dig. “As we
excavated, we dropped that metal plate down further
and further,” Cheng adds.
Overall, the work currently underway is straightforward. When the trench floor is ready, the large steel
pipe will be lowered down together with concrete
WAT E R C A N A D A . N E T
anti-flotation beams to add weight sufficient to hold
it in place so it doesn’t shift or rise upwards over time.
Crews will seal vulnerable pipe components such as
joints with durable protective wrapping to prevent
corrosion, then pour controlled-density fill into the
trench for backfilling to prevent voids forming when
groundwater inevitably returns.
Controlling traffic flow close to the project site is
also crucial because some sections of roadway are fairly
narrow even without lane restrictions. “A number of
gravel and concrete businesses run their trucks down
Pipeline Road, and people live in the area as well, so it’s
challenging to manage the traffic there so we’re not too
impactful,” Cheng says. The project has also required
storm sewer, sanitary sewer, gas line and other utility
relocations. “It’s just the overall scale of the operation,”
Cheng explains.
Even with work underway close to the surface, the
project team is deep into planning the two-kilometre
tunnel through City Centre. Plans call for entry and
exit shafts reaching depths of about 60 metres at
each end, with a tunnel boring machine setting out
at Guildford Way and drilling southwards towards a
receiving yard at Dewdney Trunk Road at Westwood.
The steel pipe will measure 3.5 metres in diameter,
slightly wider than the three other sections, and crews
will contain it within a liner likely made of concrete.
“To avoid impacts to the downtown core we determined that it was best to tunnel it,” Cheng says. “It’s a
city-centre downtown core. There’s lots of traffic, lots
of impacts, so tunnelling made sense.”
While the project is scheduled in phases, the new
system won’t be commissioned until the last pipe is
laid and all nuts and bolts are in place. “As each section
gets done, we’ll get the contractors to connect to the
previous section that was built. Then at the end, once
everything is connected, our crews will tie in at the
north end and at the south end, and that’s when we’ll
put the whole main into service.”
With the work also being done to enhance the reservoir and its intake tunnel and treatment plant, Cheng
expresses confidence that the new water main will
prove resilient in the face of uncertainty and adversity.
“It’s a generational project that’s going to have huge
impacts. Short-term, obviously, there’s construction
impacts, but long-term it’s going to have huge benefits
for the region.”
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