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WJ News

Latest News and Updates from WJ Groundwater and across the Industry.

Dewatering and Groundwater Treatment

Dan Carpenter October 27, 2023

Residential Dewatering and Treatment

Whilst much of WJ Canada’s work has been on transport and infrastructure projects, we are equally at home providing groundwater control services on residential projects.

Complex Conditions

For this project WJ were engaged to provide an upgrade of an existing dewatering system to meeting unexpected groundwater conditions on site, and to ensure the works could take place successfully. When WJ were brought on board we were immediately met with a complex geology consisting of distinct aquifers and water flow conditions. Thick, highly permeable, sandy aquifers were present, with low permeability peat layers on the east side of the site.

Dewatering and Treatment

WJ’s flexible dewatering solution was successfully implemented to accommodate the varying groundwater conditions by reducing the natural groundwater levels by 10m in a 13m deep excavation.

In addition to the dewatering system, a water treatment system was also upgraded to accommodate the high flows of around 1,000,000.00 l/day, as well as treating the water so they iron rich water (100mg/l) were clear by the time they had passed through the various media filters and bag vessels (which included automatic backwash operations), without interrupting the onsite dewatering works.

…and monitoring

A remote monitoring system covering all dewatering and water treatment system components and including water level sensors were also installed within the scope of this project. Thus, all the details of dewatering and water treatment works happening on site were instantly visible and traceable.

WJ wellpoint installation at UOIT September 2019

LRT Extension Project in Toronto

Dan Carpenter October 27, 2023

WJ keep Toronto Moving

The expansion of the Toronto Light Rail Transit (LRT) network has provided WJ with a steady stream of work since WJ Canada was formed in 2016, work which continues to this day.

Throughout 2022 WJ undertook a variety of pumping tests and other hydrogeological investigations at a number of key sites along the LRT alignment. Alongside these investigatory works, WJ have provided robust dewatering solutions to maximize the drawdown at the Tunnel Boring Machine (TBM) intervention sites.

TBM Interventions

These interventions are locations along the alignment where maintenance is performed on the cutting face of the TBM, and therefore, for safety reasons, zero hydrostatic pressure is required. This requites an extensive and robust dewatering system – something WJ are experts in providing.

In addition to investigatory and dewatering works, an extensive array of groundwater monitoring wells was installed along the alignment to be used for pre-commissioning testing and system monitoring.

LOCATION: Toronto

Finch West LRT Project, Toronto

Dan Carpenter February 8, 2021

The Dewatering Vendor of Choice for Toronto LRT Projects

The success of the Eglinton Crosstown LRT (Light Rail Transit) project (also known as Line 5) in Toronto, where we have provided dewatering services to great effect on 12 of the 14 stations, has led to WJ becoming the dewatering vendor of choice for large LRT projects in the city.

Finch West LRT

Building on the success of this project, WJ have recently begun work on the Finch West LRT project. The Finch West Project (also known as Line 6) continues the expansion of public transit services in Toronto and is expected to carry some 40,000 passengers per day by 2031. Our initial works on the project will cover the two new underground station that are due to be constructed: the new terminus at Humber College and the new interchange terminus at Finch West, where the new line will connect with the Line 2 extension to York University.

Finch West Station

The Finch West Station includes a deep connection to the existing subway station and an underground track crossing – in short a deeply complex project, that will require the installation of deep wells, wellpoints and eductor wells. Fortunately these types of projects are second nature to WJ and perfectly demonstrate our creative and flexible approach to providing successful and efficient dewatering solutions that we have shown on thousands of project in Canada and elsewhere across the globe!

Humber College Station

The Humber College station, located adjacent to Highway 27 will be another opportunity to demonstrate many of the dewatering techniques that were used to great effect on the deep excavations of the Eglinton Crosstown project.

We are proud to be given the opportunity to contribute to this exciting project, and the continued expansion of public transit projects in Toronto, and look forward to its successful completion, and having the opportunity to hop on board!

LOCATION: Toronto
CLIENT: Metrolinx

Sump Pit Completion at Caledonia Station

WJ Group Admin July 18, 2019

The Eglinton Crosstown represents the largest transit expansion in Canada. It will completely change how residents and visitors in Toronto get around this great city. 19 kilometres of new light rail – 10km underground – that starts in the west end and travels right through the city to the east end, with 25 new stations and stops linking to 54 bus routes, three subway stations and various GO transit lines. That means shorter commutes, reliable and convenient transit and cleaner air.

But that kind of huge infrastructure project doesn’t come without more than its fair share of challenges! This was exactly the case at the Caledonia Station site. The ground conditions we encountered there were among the most challenging we’ve had to deal with in WJ’s long and successful involvement with the Eglinton project. However, we were confident that given our decades of experience and industry-leading practices, we were up for the challenge!

Eglinton Crosstown Caledonia Station dewatering

Multiple clay layers ran through the site, cutting up the aquifer into many different pieces. Factor in a massive 30m deep excavation, shored by soldier pile and lagging, and we had all the ingredients for a dewatering nightmare.

After coming in to rescue project developers, CTS, from an inferior dewatering system that couldn’t tackle these site conditions, WJ got to work with Crosslinx to uncover these layers. Our expert water management consultants deciphered the geology of ancient glacial lake bottom deposits that lay buried deep underground across Toronto.

However, in the world of dewatering, clay is clay. No matter how thin, a continuous layer can quickly change dewatering requirements.

Our deductions were proved correct when we uncovered a 1-inch thick layer of clay across the entire site. Working tireless to dewater each and every layer, WJ battled the water towards the base of the sump pit. From there. our sump pit dewatering actions provided a site suitable for CTS to complete their excavation and commence construction of the station from the bottom-up.

“WJ helped the Caledonia team through some very challenging conditions at Caledonia. They were committed and worked with us every step of the way. WJ’s can-do attitude was refreshing and much appreciated on this difficult and challenging site.”

– Daniel Sanchez, Project Manager, Caledonia and Keelesdale Stations.

LOCATION: Oakwood Station, Eglinton Crosstown Light Rail Transit
CLIENT: Crosslinx Transit Solutions
MAIN CONTRACTOR: CTS

Cross Cut Completion at Oakwood Station

WJ Group Admin July 18, 2019

The Eglinton Crosstown Light Rail Transit (ECLRT) project consists of 19.7 km of light rail transit running along Eglinton Avenue from Mount Dennis in the west to Kennedy in the east. The project is being designed and constructed by Crosslinx Transit Solutions (CTS).

With such an important and flagship infrastructure project, under constant public scrutiny, given the build disruption to local communities, the stakes were high. CTS needed a true water management partner who would work with them right through to the end. And that’s where WJ came in.

WJ was called in from the UK to take a look at dewatering requirements of the Eglinton Crosstown Project – a challenging commission, which combines difficult dewatering conditions with innovative construction techniques. Several of the stations within the Eglinton project are being constructed using a unique soil mining technique, known as the New Austrian Tunnelling Method. This meant that our dewatering solutions had to be just as innovative in order to succeed.

Right from the start, the Oakwood main entrance access (called the cross-cut) was flagged as the most challenging aspect of the project. A silty, low-permeability soil matrix that fines towards the bottom of the excavation was located just above a clay interface. Using, wellpoints, eductors, and deep wells, installed from the road surface and from confined spaces in TBM tunnels and mined caverns, WJ was able to complete this substantial dewatering feat, without any delay to the CTS mining schedule.

As everyone in mining knows: the mining can never stop!

WJ ensured it never did.

LOCATION: Oakwood Station, Eglinton Crosstown Light Rail Transit
CLIENT: Crosslinx Transit Solutions
MAIN CONTRACTOR: CTS

Eglinton Crosstown Light Rail Transit System

WJ Group Admin July 16, 2018

The Eglinton Crosstown Light Rail Transit (ECLRT) project

Bromley South Central, London

Dan Carpenter October 9, 2017

This contract took WJ to Bromley, in the heart of South London, to take part in a new major regeneration project.

Royal Hospital For Sick Children, Edinburgh

Dan Carpenter October 9, 2017

The Royal Hospital for Sick Children has been based on it’s existing site in the heart of Edinburgh since 1895, however in 2005 it was decided by the local NHS Trust that a more modern facility should be constructed adjacent to the existing Edinburgh Royal Infirmary at Little France on the south-east edge of the city.

Ipswich Tidal Barrier

Dan Carpenter July 19, 2017

This contract took us to the heart of Suffolk, to aid with the construction of a new Tidal Barrier Gate for the River Orwell, to reduce the risk and impact of flooding to the coastal town of Ipswich.

Lodz High Speed Rail Interchange, Poland

WJ Group Admin August 19, 2015

This highly exciting contract allowed WJ to branch into an entirely new area of expertise.