Hook Sea Outfalls


Project: Hook Sea Outfalls

Scope: De-silt outfall, tuberculation removal and NDT wall thickness

Location: Hook, Southampton

An initial investigative survey using one of our smaller survey class Pipe Inspection Vehicles (PIV), revealed that Hook Long Sea Outfall; a circa 750mm x 1900m long, cast iron construction outfall was heavily blocked with silt & debris and on exposed areas of wall there was a proliferation of tuberculation blisters.

Earlier attempts to clean the outfall using conventional HP jetting techniques had failed and we utilised our winched folding brush system to remove around 100 cubic metres of silt, sand & debris. We also utilised our cleaning system fitted with circumferential steel wire brushes for removal of the tuberculation, which we combined with HP jetting for the final pre-NDT survey clean.

We carried out a series of ‘spot’ Non-Destructive Tests on pre-determined locations to ascertain average remaining wall thickness to enable the Client to determine remaining useful asset life expectancy. Site conditions were harsh, very changeable and we were working in an environmentally sensitive area (SSSI site). The
methodology had to be precise and followed to the letter.

Testimonial: They were the only contractor that could provide 4-Delivery with the range of disciplines suited to the Hook Sea Outfall works. Required disciplines included: diving, internal outfall inspection, removing silt & debris, NDT testing and localised repairs. The site was Environmentally sensitive and the project had to be completed during the Wildfowl hatching season.

All services were provided seamlessly, efficiently and to the highest standards…great work.

Andrew Marsh 4-Deliver, Southern Water, Project Manager