REPLACEMENT OF a structurally unsound section of the two year old Jubilee River flood relief channel in Berkshire begin this month, the Environment Agency said this week.
Contractor J Breheny has been brought in to beef up around 300m of embankments near Datchet.
Investigations by consultant Atkins have revealed these could collapse under high flood flows.
The work will cost £1M and will take until November.
Existing earth embankments will be ripped out while the river is shored up with cofferdams.
The embankments will then be rebuilt with earth reinforced by geotechnical membranes.
Atkins identified weaknesses in the original Balfour Beatty constructed embankments in a report for the Environment Agency.
It said that the slopes were too steep, with the factor of safety falling below 1.0 in places.
'If we had to call on the channel to its full design capacity we have some concerns as to whether the embankments would stand up, ' said Environment Agency project manager Tim Chin.
Atkins was called in to investigate the performance of the channel following flooding in January 2003.
Operation of the £105M scheme prevented flooding to around 1,000 properties in Maidenhead, Windsor and Eton.
But there was widespread flooding downstream of the confluence of the channel with the Thames near Datchet.
Residents' groups have since claimed that water was flowing through the embankments, surcharging a nearby stream running alongside the channel, before flowing across fields into Datchet.
The Environment Agency disputes this claim, but has admitted that the channel's embankments suffered damage in several places during the floods.
Atkins' final report on the channel's condition, true capacity and necessary repair work has yet to be made public.