The Environment Agency has started legal proceedings against consultant Lewin, Fryer and Partners (LFP) for the design of the structures damaged during the January 2003 floods and the cost to repair them. LFP, now part of Black & Veatch, was consultant throughout 20 years of feasibility studies, planning, design, public inquiry and construction on the £110M scheme, which opened in November 2001.
The 11km long channel was intended to relieve flooding by diverting flood surges of up to 215m3/s from the River Thames around Maidenhead, Windsor and Eton. But in January 2003 a peak flow of 144m3/s caused major damage to the channel. Investigations by consultant Atkins revealed a catalogue of design and construction defects limiting the channel's capacity to just two thirds of its design capacity.
They include fundamental mistakes such as building banks too low, using inappropriate materials and failing to follow standard design criteria (NCE 19/26 August 2004). The Environment Agency has since spent £3.5M carrying out repairs and raising banks. This work has raised capacity to 170m3/s, with further work this summer aimed at raising capacity further. But the Agency accepts that the full design capacity may never be achieved. 'We are working to enhance the current capacity of the Jubilee River through raising bank heights along targeted stretches of the river. 'Further planned works are the construction of a flood wall at Blackpotts, raising the bank height downstream of the Myrke Foot bridge, raising the bank height up stream of Chalvey rail bridge, and raising the bank height upstream of the A4 road bridge.' These will be completed in 2006,' the Agency said in a statement.