Prefabricated Ridgistorm-XL solution chosen for Welsh Water capital works scheme

Polypipe’s ability to prefabricate a modularised drainage solution has been utilised as part of a flood alleviation scheme for Welsh Water.

The Gulls Way capital works scheme in Heswall, Wirral, required combined sewer improvements along an existing residential street where the existing 450mm concrete sewer had insufficient capacity to cope with high volumes of rainfall, causing the surrounding road and a number of properties to flood during storm events.

Working closely with Welsh Water, consultant engineer AECOM, main contractor Costain and groundworker Mulcair Ltd from an early design stage, Polypipe supplied a fully engineered Ridgistorm-XL attenuation system comprising of a dual pipe run to provide an additional 360m3 of storage.

As well as providing Ridgistorm-XL pipes in 900mm diameters, Polypipe also utilised its large diameter piping and its ability to pre-fabricate structural components to create a number of 1500mm chambers and unique modular ‘H’ access manholes to sit between the pipe runs. Saving time and costs whilst minimising disruption to residents in the immediate local area was vital, which is why a pre-fabricated system from Polypipe was ideal for the project.

The Ridgistorm-XL system limited the amount of work undertaken in the Highway and ensured that work was able to progress much quicker than if more traditional methods had been used.

Polypipe was able to deliver the chambers to site with internal benching and step runs incorporated, and the light weight nature of their plastic systems – combined with Ridgistorm-XL’s factory fitted lifting points – meant that the new combined sewer system was able to be installed much quicker and safer than would have otherwise been possible, minimising the project’s impact on road users and local residents.