The North Sea Flood of 1953 was
caused by a combination of a high spring tide and severe windstorms, and in
some areas led to the sea level being more than 5.6 meters above its normal
height. It was one of the most devastating natural disasters ever to be
recorded in the UK with 1,600 km of coastline damaged; 30,000 people evacuated,
24,000 homes affected with a consequent death toll of 307. This incident
prompted calls for a mechanism to protect the capital from similar events. This
led to the construction of the Thames Barrier.
Construction began in 1974, and
in addition to the barrier, the flood defences for 11 miles downriver were
raised and strengthened. The barrier was officially opened by the Queen on the
8th May 1984, with a total coast reaching £1.5 billion (in 2014
prices). It is built across a 520-metre wide stretch of the Thames , and
divides the river into 6 navigable spans.
By holding back the tide, the
barrier creates more space in the river for excess water from upstream to flow
down. At low tide, the Thames Barrier is then opened and the floodwaters flow
to the sea. Last winter the UK had the stormiest and wettest period of weather
for a century with the barrier closed a
record 50 times over the winter period - compared to just 35 times between 1990
and the end of 1999.
In terms of the future of the
Thames Barrier, a project entitled TE2100 aims to develop a tidal flood risk
management plan for the Thames Estuary through to 2100. This strategy takes
into account a changing climate, changes within the estuary and the problem of
ageing flood defences. The project has a 40 year vision, producing
recommendations for the first 25 years for 8 geographical areas. Public
consultation has played an important part in the development of the TE2100
Plan.
The Environment Agency funded
extensive research on changes in fluvial flows, sea storm surges and sea level
rise. This research also featured 300 investigations into how tidal flood risk
is increasing in the Thames Estuary due to ageing flood defences and the
increase in people living and working within the floodplain. The conclusions
drawn from these studies are that it is unlikely that major changes will be
needed to be made to the existing flood defence systems and structures for the
next 25 years. From 2035 the plans for the barrier are to focus on renewal and
reshaping of the riverside and the upgrading of existing defences.
The Thames Barrier, with some
modification, has the potential to continue to protect London though this
century (based on current climate guidance). It may prove more cost effective,
as a future strategy, to build further defences downstream in around 2070 to
support the Thames Barrier towards the end of its lifespan.
Author: Becky Forshaw, Argyll Environmental
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