Disappointed with previous visions for the Thames, Tim Beckett, co-founder of the marine consultancy engineers Beckett Rankine, has developed a vision that places planning for London’s future flood defences at its heart.
His aim was to create a “deliverable visionary vision” and he launched his Alternative Vision for The Thames at the Institute of Civil Engineers. The timescale is to 2050 because, as he points out, the greatest challenge and opportunity is London’s future flood defences and the successor to the Thames Barrier.
He argues that “we need to start planning for them now because the resolution of a number of other key issues for the river depends on the flood defence solution”. He believes that there will be a new barrier and proposes Long Reach, below Dartford Creek, as the logical location.
A key consideration he raises in his vision is whether the new flood barrier could also be a power-generating, half-tide barrage which could open many attractive possibilities. Once the Tideway Tunnel is built, preventing most sewage overflows into the river, the need for tidal flushing will be reduced and a half tide barrage is a possibility.
In terms of transport a half tide barrage would allow more space on the river for navigation, reducing navigational risk.
It would also enable river bus services to be extended from west of Putney to Hammersmith and beyond.
Excitingly the retained water level opens up the possibility of floating markets with goods being brought into the centre of London and sold direct from barges to consumers, as in Venice or Amsterdam.
With tidal range reduced by a barrage the new bridge crossings that are needed in east London could be low level to facilitate cycling and walking, but still high enough for normal river traffic.
There would also be many more possible sites for the additional piers that are required in central and east London to minimise the need for vessels to cross the river.
There are also environmental benefits to a barrage. For example electric vessels would become a practical option – with reduced tidal range vessels don’t need to be so powerful to battle against the tide.
Plastic waste is a key issue for the river; whatever the replacement structure for the Thames Barrier is it could have a flotsam collection facilities to prevent waste from reaching the sea.
However, there is a downside to a half-tide barrage. As Tim points out it would change the river’s ecology. Significant areas of intertidal foreshore would become subtidal and although new intertidal areas could be created these would be in a different location.
To read the full presentation of the vision click here