Case Study: Hampton WTW Eel Intake Screens

Hampton WTW Eel Intake Screens

Contract No:C1278
Client:Costain Atkins B&V JV
Location:Hampton Water Treatment Works
Value:Approximately £120,000.00
Summary:Supply and installation of 8no 15m long Tubular Fender Piles to provide impact protection from river vessels to the newly constructed eel screens.

Sheet Piling (UK) Ltd have recently completed the installation of impact protection Tubular Fender Piles along the River Thames at Hampton working for Costain, Atkins, B&V JV working on behalf of Thames Water under the Eight2O Alliance.

The new eel screens were required since in January 2010, the Eels (England and Wales) Regulations 2009 came into force which gave the Environment Agency new powers to protect and conserve the population of eels in the rivers of England and Wales.

The abstraction point for Thames Waters’ Hampton Water Treatment Works removes water from the River Thames which is critical for maintaining reservoir levels for London’s water supply.

To fulfil the requirements of the Eel Regulations, Thames Water were required to undertake the Hampton Eel Screens Project as part of the AMP6 programme of works delivered by the Eight2O Alliance.

Following a previous successful scheme at Island Barn Reservoir, Sheet Piling (UK) Ltd on behalf of the JV we were engaged through a Professional Services Contract in order to advise the client on a cost-effective, constructible solution for the works at Hampton WTW.

During the initial discussions, Sheet Piling (UK) Ltd were asked to consider both a marine and land-based solution. Following a detailed and thorough assessment Sheet Piling (UK) Ltd chose to complete the works from land. Choosing this method had its own issues and required engagement with a specialist temporary works designer, Byland Engineering, to assess the existing river wall for stability and design a suitable working platform to allow the use of a 250te lattice boom crawler crane.

Given the location of the works and the sensitive receptors, including local water bourn businesses and house boats along the River Thames, Sheet Piling (UK) Ltd were required to complete the works with minimal disruption along the watercourse in a timely manner.

Utilising Sheet Piling (UK) Ltd.’s internal plant the works were undertaken at a maximum working radius of 40m using conventional piling methods. This consisted of a lower piling frame supported over water by 4no ‘H’ piles driven into the existing London Clay, to provide a stable temporary support frame. At each location, the 15m long 508mm x 16mm Tubular Fender Piles were driven to vibratory refusal using a PVE25M crane suspended vibratory hammer attached to a driving plate welded to the head of the tube. Subsequently, the tubes were then driven to toe level using a BSP HH357 hydraulic impact hammer complete with tube skirt guide.

The installation commenced in March 2018, completing in just two weeks, to the mutual benefit of the client and Sheet Piling (UK) Ltd.