River Winster

River Winster

In July 2020, VolkerMarine Services was awarded a contract by VolkerGround Engineering to supply a turnkey pontoon solution as part of emergency flood defence works in Grange-over-Sands, Cumbria.

The pontoon solution was required to support a 60t excavator with Movax, to facilitate emergency works to the unstable and failing embankment on the River Winster and prevent flood damage to the houses adjacent to the riverbank.

Over a three-day period, the VolkerMarine Services' marine installation team mobilised on site and installed 21 standard pontoons and 4 spud pontoons, along with the necessary ancillary equipment, including winches, roller fairleads, handrails, gangways, steel and wood mats, compressors, pumps and a toilet.

Our team also supplied a mini tug and workboats to successfully mobilise the pontoons and support operational movements of the pontoon.

The final design package included stability calculations for operating conditions, a ballast plan for loading and operating, a storyboard for loading, as well as interface loads for ramps to shore and ramp design. VolkerMarine Services also had a designer on site during the project, to sign off the pontoon setup, ballasting conditions and ramp installation, prior to and during loading, and also when disembarking the excavator.

Due to the very narrow riverbed, water levels fluctuated dramatically over the period running up to mobilisation, restricting the size of the pontoon setup. VolkerMarine Services worked closely with VolkerGround Engineering to tailor our installation method and approach, and overcame the fluctuating waters by ballasting, so that the long reach excavator could work at maximum reach.

Access to the site was very restricted, and our team had to carefully schedule all deliveries to ensure that only one lorry was on site at any one time.

The turnkey pontoon solution provided by VolkerMarine Services ensured that the site team did not have to worry about the pontoon set up and could step aboard the fully equipped pontoon to progress with the piling works.

“The works were successfully completed by the end of 2020 as planned. This was only possible due to the collaborative and open approach to design requirements and build-ability issues. All parties should be proud of the part they have played in this first-class example of collaborative delivery.”

Julian Wilson VolkerStevin contracts manager