A £5m project by Southampton-based engineering and construction company Trant is under way to build extensive flood defences for a substation on the flood plain of the River Severn in Gloucestershire.
Following a rigorous tender, international power company National Grid appointed the multi-disciplinary contractor to carry out works around the boundary of the site at Walham near Gloucester.
The scheme was required following flooding in July 2007, which became national news due to the potential of widespread disruption to essential infrastructure, including power and water supplies. River levels in many locations were the highest on record.
Supplying half a million people with electricity, the substation at Walham was saved from having to be shut down thanks to ‘Operation Giraffe’.
In a race against time and tide, National Grid, with the assistance of the military, Environment Agency and fire and rescue service, successfully built emergency protective walls around the perimeter with sandbags.
Flood water was removed with pumping equipment.
To reduce the risk of such an event happening again, Trant is creating steel sheet pile walls, which will be encased in concrete, to protect the substation.
To enhance operational efficiency, Trant bought a new JCB JS260 26-tonne excavator with a specialist, computer-controlled Movax piling attachment.
As principal contractor, Trant has up to 30 operatives a day working on the 13-month scheme, due for completion later this summer.
Alistair Parker, Trant Contracts Manager, said: “We’re utilising the best in engineering and construction skills to deliver for National Grid safely on time and within budget whilst aiming to exceed contract expectations at all times.
“This is a demanding job in many respects, given the fact that there are just a few metres shy of 1km of sheet pile walls to install in challenging ground conditions, with underground and overhead services to contend with. Furthermore, heavy rain earlier this year hampered progress as the river repeatedly flooded.”
He added: “Our new JCB JS260 26-tonne excavator, with the Movax piling attachment, is enhancing operational efficiency and is definitely the way forward. We’re impressed with the joint capabilities and ease of use.”
The project is the latest awarded to Trant by blue-chip companies, such as National Grid and Siemens, in the power & transmission sector.
They include the award-winning £17.4m contract for the first and second phases of the Cleve Hill Onshore Substation, London Array Wind Farm.
Built after 550,000 tonnes of earth were excavated – and reused on site as screening mounds – the substation near Faversham in Kent will flow energy from the largest offshore wind farm in the world to the 400kV national transmission system, powering up to 750,000 homes.
