Thames Barrier could move in climate change plan

It is one of four options discussed in the Thames Estuary 2100 project, which claims £8.4billion will be required to maintain and upgrade the capital's flood defence network over the next nine decades.

Thames 2100 technical strategy manager Rachael Hill said: "We know the Thames Barrier will keep operating through to the end of the century if we make major modifications to it.

"Another option may be to construct a new barrier. Our preferred location is Long Reach near Purfleet, but we're also looking at a location in Tilbury.

"We're going to see an increase in sea levels and rainfall, and we know we're going to have to close the barrier more frequently. By 2030, it's predicted it will have to close 30 times a year. By 2070 it will be almost 50 times a year, and that will have a huge impact on the river.

"If we build a new barrier downstream, there would be the potential for lower tidal walls between the two locations. It would reshape and regenerate the riverside by giving more people access."

The three-month public consultation on London's future flood plan began this week, following a six-year investigation of the impact of climate change on the estuary's 330 kilometres of walls and defences. The results could affect 1.25million people, over 500,000 homes, 40,000 businesses, 400 schools and 16 hospitals in the potential flooding area.

The agency currently believes that climate change could raise water levels by between 19.4cm and 87.8cm by the end of the century. It claims the Thames Barrier is sturdy enough to withstand this rise until 2070, when it will either need to be replaced or modified. Other options include adding locks to the barrier to reduce the impact of closures, and storing water from the channel in flood plains in an area between Tilbury and the barrier.

The Environment Agency currently spends £55million a year maintaining its flood defences. It estimates this process will cost £1.4billion up to 2035, while major renewal or improvement up to 2069 will come to £3billion. The final phase - which could see the Thames Barrier shift eastwards - has been estimated at £4billion. The idea of sharing the cost with affected businesses has not been ruled out.

The final proposal is expected to reach Government by January 2010, with a view to implementing action in the mid-20th Century. The Environment Agency will perform checks every ten years to review its predictions on sea level rises.

Ms Hill said: "The impact of tidal flow would be absolutely catastrophic.

"This is the first time major action on London's flood defences has been taken that is not in response to a flood.

"We want to continue to build confidence among home and business owners in how flood risk is managed. It's inconceivable that anybody would not take this action."

To take part in the consultation, go to environment-agency.gov.uk, email TE2100@environment-agency.gov.uk or call 08708 506506.