Whilst WJ are well known and respected as one of the leading dewatering contractors in the UK, we have many other services within our oeuvre. We recently demonstrated one of these whilst undertaking in-tunnel probe drilling as part of the Thames Tideway works at the Dormay Street Shaft in Wandsworth.
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On the 17th and 18th of September 2018, the British Geotechnical Association and Engineering Group of the Geological Society hosted the first major conference on Chalk in almost 30 years, right on WJ’s doorstep, at Imperial College in Central London.
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Back in May WJ UK had the honour of being included in articles in the British National Press because of our work on the Thames Tideway project. This time we’ve gone one step better and can now claim to be ‘as featured on TV’!
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WJ have been an established part of the dewatering game in the Middle East for over 15 years now since providing the dewatering for the Dubai International Airport Terminal 3 development back in 2003, with offices in Dubai since 2005 and our Qatar office due to celebrate its tenth anniversary in 2019. January this year marked our expansion in to nearby Kuwait when we were appointed by the Main Contractor HDEC (Hyundai Engineering and Construction) working under the Client KIPIC (Kuwait Integrated Petroleum Industries Company) for the Al Zour Liquefied Natural Gas (LNG) Terminal Project.
The new terminal is located in the Al-Zour region of Kuwait near to the border with Saudi Arabia, approximately 90km south of the capital Kuwait City, and will include eight LNG storage tanks, each with a capacity of 225,000m3, and associated marine facilities.
Although the sandy ground conditions were prime dewatering territory, the project had the potential to be particularly challenging. Not only would WJ be working in a new country which always brings with it a steep learning curve, but the structures to be dewatered were far from insubstantial – the intake and outfall structures which our systems were going to target were approximately 500m by 200m in size, and up to 15m deep, and the works would be taking place on land reclaimed from the Arabian Gulf. Fortunately there are few things WJ love more than a challenge!
In order to complete the works in a swift and prompt fashion WJ utilised one of our trusted partners, Trevi, to work alongside our own SM14 drilling rig. In total 62 dewatering wells and 10 groundwater monitoring standpipes were installed for the intake structure, and another 21 for the outfall structure. The initial plans were to install both perimeter and internal dewatering systems to draw the groundwater level down to enable a dry excavation, however the perimeter system proved to be so successful that there was no need for the internal system to be installed.
Although the works began at the start of 2018 when the temperatures in Kuwait are relatively comfortable, as the project has progressed the day time working temperatures approached the 40⁰C’s and as the Muslim holy month of Ramadan arrived it became necessary for some of the installation works to be undertaken during the night, with only monitoring to be undertaken during daylight hours. This however had no impact upon the expert level of service WJ are known for.
Hopefully this is the start of long and successful times for WJ in Kuwait and helps to strengthen our position as one of the go-to contractors for any technically challenging dewatering project across the Middle East.
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It’s not often WJ are featured in the national press, however we very recently had the honour of appearing in articles on both the Daily Mail and London Evening Standard websites about the Thames Tideway project currently underway through central London.
Much of the current sewer network underneath London date back to the mid-19th century when they were constructed under the guidance of the visionary engineer Sir Joseph Bazalgette. Over this time the population of London has more than doubled, and therefore these Victorian Sewers lack the required capacity. To tackle this problem a new 25km ‘super sewer’ running along the tidal section of the River Thames, through Central London, is being constructed, with new Combined Sewer Overflows (CSOs) and shafts being constructed at a number of iconic sites including Blackfriars, along Chelsea Embankment, along Albert Embankment, along Victoria Embankment and adjacent to Battersea Power Station at Kirtling Street.
The Kirtling Street site, is one of a number where dewatering is required, and there are few companies more accustomed to the dewatering requirements in Central London than WJ! The challenges of dewatering in the Battersea area are particularly well known to WJ having undertaken works for the nearby Battersea Power Station redevelopment, the New American Embassy in Nine Elms, and the Northern Line extension, as well as numerous smaller projects.
At the Kirtling Street site a 32m diameter shaft, over 60m deep, is being constructed as part of the Tideway works. As the shaft is being constructed with a diaphragm wall the groundwater in the upper aquifers of the River Terrace Deposits will be cut-off, however it was necessary for WJ to install passive relief wells in to the Lower Aquifers of the Chalk to relieve groundwater pressures and to ensure that as the shaft was sunk, the stability of its base was maintained.
The purpose of the shaft was to allow the construction of Tunnel Boring Machine (TBM) launch adits. To allow these adits to be constructed dewatering was required, predominantly installed from ground level, where 16 new wells were installed to dewatering the Chalk and Lambeth Group (in addition to existing wells). However access wasn’t always available from ground level, so WJ were required to use their experience of in-tunnel drilling from Crossrail to install over 60 inclined tunnel and shaft wells to again dewater the Lambeth Group.
The Thames Tideway project is expected to play a major part of WJs near future with dewatering required at a number of sites throughout London prior to the expected completion date of 2023.
You can read more about the projects at:
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WJ are once again showing our technical prowess with another challenging project in Anchorsholme; dewatering a cofferdam in the Irish Sea!
WJ have been working in and around Blackpool for several years now, having completed the Anchorsholme Park Storage Phase 1 and Phase 2 works for Ward and Burke and the Lennox Gate project for Ward and Burke and JN Bentley, both during 2016 and 2017.
Our latest project, working with the CH2M HILL – VolkerStevin joint venture, C2V+, was to aid the construction of a new 6m by 20m cofferdam in the Irish Sea, directly off the coast from the Anchorsholme Park Storage site. The particularly challenging aspect of this project was the offshore location of the cofferdam, fortunately WJ have undertaken several similar projects to this in recent years in Ipswich and Dover.
The dewatering system comprised eight 9.5m deep deepwells installed around the internal perimeter of the cofferdam, installed using a rotary drilling rig, in to interbedded sand and clay deposits during February 2018.
The first technical challenge on this project was the installation of the wells themselves. It was only possible to install during the two 6-hr low tide windows each day, as during high tides the cofferdam would be flooded. During each of these windows it was necessary to pump out the cofferdam, crane the drilling rig in to position, drill, seal off the works so they wouldn’t flood when the tide came back in, and remove the rig from the cofferdam. Fortunately due to the meticulous planning of the works by the WJ Project Engineer, Michael Cummiskey, the wells were all successfully installed during the planned installation period.
The second technical challenge was also a result of the offshore location. As the cofferdam would be flooded during high tides it was necessary for the WJ control cabin and generators to be located onshore on an existing revetment, above the maximum tide level, with cables running between the cofferdam and the cabins along the beach and existing sea defences.
Despite the best efforts of the Irish Sea the target drawdown was successfully achieved and the pumping is due to continue until the end of April.
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WJ Groundwater have a long and enviable reputation as technical leaders in the dewatering industry, renowned for being able to provide a professional and practical solution to groundwater problems. In order to reinforce this position, and to enhance our reputation as the ‘go to’ company for overpumping, WJ have invested in some new larger capacity pumps to add to our already extensive fleet.
The new pumps were purchased to aid with another high-profile sewage overpumping project at the Dubai Mall, the largest shopping mall in the world with over 1200 stores! The pumping setup included a mixture of WJ’s fuel efficient 16”, 12” and 6” diesel surface pumps, chosen to cope with both the project requirements and to minimise overall project costs to the client, HLG.
As is often the case in this industry, the biggest challenge WJ faced during the project was logistical. The site was located with an elevated bridge section on one side, and a live road on the other, with the requirement for several hundred metres of the overpumping system, including a 400mm diameter pipe, to be buried through a live construction site. With WJ’s characteristic careful planning, we were able to liaise with local authorities for road closures and the installation works proved to be a great success!
The system continues to perform extremely well even with the significant changes in flow between peak and low flow times of the day.
Dubai General Manager Oliver Vincent noted that the success of this project was a perfect example of why WJ have grown so quickly in this newly developing market:
“It was clear to us that the market wanted a reliable overpumping contractor that not only rented pumps, but also gave a complete service from design, to installation, to operation and maintenance. Yes, we do offer a rental only service, but often we find that clients don’t want to worry about sewage overflowing at night, so they would much rather give the complete package to WJ and rest easy. As we already had the design expertise, plus the backbone of supervisors, engineers and mechanics required to service the system, it was a natural progression for us. As you can imagine, it is very exciting for us as we get to work with some amazing pieces of equipment, with some very high flows and on some fantastic projects.”
Call WJ Groundwater today to find out how they can help you with your sewage and water control project. WJ are happy to provide advice at early design and prices at tendering stages.
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WJ Groundwater are pleased to announce that one of our recent projects in Scotland has been announced as the winner of a prestigious industry prize. WJ were awarded the contract to undertake dewatering works at the site on the outskirts of Glasgow between July 2015 and July 2016, and helped to contribute to the project which was recently awarded ‘UK Project with a Geotechnical Value up to £1.0m by Ground Engineering magazine.
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WJ’s latest Canadian employee inspects one of our pumps in the Eglinton Crosslinx tunnel in Toronto.
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Spring has been another busy period for WJ Groundwater with new contract awards in every corner of the UK, with projects starting in Dover, Port Talbot, Houston in Ayrshire, the Isle of Skye and Woodsmith Mine in North Yorkshire.
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