Tuesday 14 April 2009

Thames Flood Barrier

Website: http://www.environment-agency.gov.uk/homeandleisure/floods/38353.aspx

Yesterday I went on an adventure with ABJ to the Thames Flood Barrier. I visited Thames Barrier Park on the north of the river a few years ago and have always wanted to come back and find out more about it. Since I've mainly lived in west London and the barrier is in east London I've never got around to it. Until yesterday...

We got the train from Charing Cross to Charlton station and then, AtoZ in hand, headed for the river. We found the Thames Path and got out first glimpse of the futuristic looking barrier: We approached and arrived at an ominous tunnel that went underneath through the barrier before we found outselves next to a map of the Thames river. The map showed all the towns the river past through as well as all the bridges that cross it:We continued on through a pleasant picnic area/playground to the Information Centre. There was a nice view of the barrier and across the river to the Tate&Lyle sugar factory:
We bought our inexpensive tickets at the cafe and then went downstairs to learn about why the barrier was built and how it works. It turns out that under very specific (fairly rare) circumstances London is at risk of flooding due to a freakishly high water level on the Thames:To ensure that London is safe from flooding the Thames Barrier was built. Its construction lasted 8 years in the 1970s and 80s and we watched a retro documentary about how they built it. It was an impressively epic project that required precision engineering and complicated constructions. Each tower of the barrier is based on a deep foundation of concrete that was dug into man-made holes in the riverbed.

When the barrier is activated a curved barrier is raised from the riverbed and held up against the incoming tide:
This (impressively) keeps the normal tidal level upstream while keeping the unusually high tides "safely downstream". When the barrier is up the nice picnic area and playground outside becomes flooded.We learnt about how floods happen and how bad the flood was in 1953 which spurred people to build good flood defenses. There was a fun "Countdown to Closure" panel where you could listen to the kinds of conversations that go back and forth between the managers of the barrier and the MET office etc during the 48 hours prior to closing the barrier.

Somewhat disconcertingly the final information panels explained how climate change might still put London at risk of flooding over the next 100 years (despite the best efforts of the existing barrier!).

We eventually finished at the information centre and, since it was a nice sunny day, decided to walk to Thames Barrier Park on the north side. This involved following the Thames Path to the free Woolwich ferry and then continuing on the north side to the park. On the way there was lots of opportunity for arty photos:
We passed a Chinese cash'n'carry:
and came close to the imposingly massive Tate&Lyle sugar factory:before finally arriving at the excellent Barrier Park: This well-maintained park offered some more good views of the barrier from the other side and was full of people relaxing in the sun. After our hours of walking, however, we decided to head home on the DLR:
Summary: An interesting day out that finally taught me how the Thames Barrier works!

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