We are looking back at the project we delivered for Anglian Water on behalf of the IOS alliance at Grafham Water Treatment Works in the heart of the Ruthamford area, near Huntingdon, Cambridgeshire.

The works comprised a full internal and external refurbishment of storage tank 3, in line with REG31 requirements to assist Anglian Water to maintain resilience for the next 10-15 years.

As part of the works, substantial repairs were required. The roof expansion joints had failed with extensive water ingress within the reservoir. External overbanding was required to rectify this issue. The teams had to prepare, repair and replace the existing roof joint system. Then a roof membrane was installed as well as a geo-textile mat so as not to damage the membrane. Internally, 2600 metres of existing failed overbanding had to be removed, a floor joint was prepared and new overbanding installed. A final clean flood test, inspection and chlorination was carried out prior to handing back to Anglian Water Services (AWS) operations to fill, stand and sample.

This project was a complex undertaking with many challenges throughout. The original scope was to install a new Masterseal 933/930 overbanding over the original failed Sika Combiflex system. Originally, this system would have saved money and enhanced the program. However, as the teams began to prepare the surface to receive the new overbanding, the original one was delaminating from the underlying concrete surface. Therefore, it was no longer possible to apply the new overbanding over the original and therefore had to be removed.

During the works, our commitment to using sustainable practices has remained a guiding principle. By using solar powered welfare facilities, energy efficient jet welfare units and stores used on site for the extensive power outlets required, we worked to minimise our carbon footprint whilst setting a standard for future projects.

This asset has been returned to supply and is providing wholesome drinking water to AWS customers. This project has been a testament to excellent collaborative working between Barhale, the IOS alliance and Anglian Water. Well done to the entire team for this vitally important resilience project.