Mersey Valley Sludge Pipeline River Crossing

The existing main was in such a poor state of repair that remedials had been undertaken previously, however following these it was decided that a quality permanent solution was required. The contract was awarded to VolkerStevin following other successful marine contracts carried out for United Utilities and on our proven track record for working sympathetically within the existing environment.

The works comprised the installation of 2 no. 273mm welded steel pumping mains from the North Side of the River Irwell to the South side of the river where new connections were made back to the existing mains. The pipeline was split into 3 sections:

• Section 1 was installed in the river under tidal conditions. The trench was open cut within the river using a specialist underwater rock cutter. The twin pipelines, fabricated on top of the embankment, were then lifted into position using tracked excavators. This trench was then concreted within the river using a purpose built concreting platform and project specific underwater concrete mix.
• Sections 2 and 3 were completed traditionally by open cut methods.

The works were adjacent to the largest population of Great Crested Newts in the UK and this was taken into consideration and actioned accordingly by installing fencing to prevent newts from entering the site. As the project involved working within a live river, all activities had to be planned and undertaken outside the fish spawning season; from 1st April to 1st September. The site also had a large infestation of Japanese Knotweed, Himalayan Balsam and Giant Hogweed.  T  Tool Box

Talks to the workforce were crucial to both prevent them from being spread further and also to protect the workforce.

As the project was located within the Clifton County Park, a dedicated Public Liaison Manager was deployed to keep the local community informed of all planned operations.