When a landslip on the embankment of the Aire and Calder Navigation threatened to make the commercially used waterway unstable, marine engineering specialists, The Rothen Group, stepped in to make the transport route safe and secure again.
The Aire and Calder Navigation has grown over the years and today transports significant amounts of raw materials across West Yorkshire, with oil, sand and gravel being the main goods being moved from the Humber ports. From Leeds, the line flows to the tidal River Ouse at Goole, where the docks are a reminder that the canal continues to serve its historic function of transporting freight.
Despite competition from road and rail, continual improvements over the years to the Aire and Calder Navigation means it remains a crucial logistics route, even after 300 years since it was constructed. The canal’s size is impressive, measuring 34 miles long and able to accommodate boats of up to 200ft in length that often weigh 700 tonnes or more.
As such, the Aire and Calder Navigation has to remain traversable. So, when the canal was breached in December 2020, action needed to be taken.
Taking Stock
Following an embankment collapse on the Don Drain section of the Aire and Calder line, there were several areas where wash walls and piles failed because of dramatic changes in water levels.
This resulted in a significant drop in hydrostatic pressure on the banks of the canal, causing piles and wash walls to fail and fall into the navigation. Two areas covering 300m were identified as requiring repair.
Water from the breach flooded surrounding fields in the aftermath while authorities rushed to stem the immediate risk to nearby properties and farmland. Because of the canal’s commercial importance and high flood threat, it could not be left to become more unstable.
Site Challenges
The Canal & River Trust, the charity responsible for the upkeep of the UK’s waterways, engaged JN Bentley to carry out urgent repair works and prevent a worsening situation. However, the extraordinary depth of the canal presented immediate challenges for the construction company.
Most canals are approximately between one and one and a half metres deep, whereas the Aire and Calder Navigation has an average depth of over three metres to accommodate the size of the boats that use the waterway. This meant that long stability legs were needed for boats to be able to work in remote sections of the canal, and heavy-duty long piles would be required to adequately fix the embankment slip.
Consequently, the company contacted The Rothen Group (TRG), to install an effective solution comprising of a floating platform and cantilever piles. TRG initially set up a floating platform using a wide beam pontoon and high-capacity crane boat, both with stability legs to provide a safe and unmovable base for workers to use when driving the cantilever piles into the ground. This allowed TRG’s specialist cranes and hoppers to be able to work directly on the water.
Due to the depth of the canal, the Canal & River Trust decided the cantilever piles needed to be back tied to reduce the length of the piles required while keeping the strength and structural stability of the equipment. Normally, cantilever piles would not require a back tie but since the teams working on the project could not access the site from the land, it would have been an impossible feat to get the right size kit on the water to be able to drive the cantilever piles in entirely.
TRG’s work on the Aire and Calder Navigation was also completed in keeping with JN Bentley’s ‘Beyond Zero’ health and safety scheme, which aims to go further than just minimising incidents while at work. The health and safety of all canal users including those working on site was prioritised throughout the embankment stabilisation project.
A Team Effort
The work on the Aire and Calder Navigation was a joint effort that met both TRG’s and JN Bentley’s high health, safety and quality standards. Matt Baldwin, Site Manager at JN Bentley, said: “The works on the Aire and Calder Navigation have been carried out to an extremely high standard. Communication has been great throughout the project and the whole team have always been approachable and open to discussing the best approach, which is fantastic.
“I was extremely happy with the work ethic and the long hours The Rothen Group team put in to make sure the project stayed on track. The team were also very accommodating for our visitors and clients, always taking the time to go above and beyond while answering any questions they might have.
“Most importantly, all the work was conducted safely. As on most projects, health and safety is our biggest risk and when we are working with plant on water and installing piles there’s a lot of risk involved. That’s why it’s so important that the whole team are on board with the ‘Beyond Zero’ campaign.
“I have also been impressed with the plant hire from The Rothen Group, which we are using to deliver the clay works. All the plant looks professional and well-maintained and if we’ve ever had an issue, The Rothen Group has been quick to respond. They even took the time to run an induction day which was great and just shows their positive attitude. I’m looking forward to working with the team again on any future projects!”.
Ian Rothen, Managing Director at The Rothen Group, led the repair works project. He said:
“We know that the Aire & Calder Navigation serves a very important purpose. When we got to site, we knew our mission was not just to repair the damaged wash walls, but also to prevent the issue from happening again.
“The collaboration with JN Bentley was crucial to health and safety, given that we were operating heavy machinery on water. It’s reassuring to know Matt and his team were pleased with our approach, and our solutions are now in place to futureproof the safety of this important stretch of waterway.”
