Why thames barrier was built

When not in use, the gates rest out of sight in curved recessed concrete cills in the riverbed, which allows river traffic to pass through. Before the barrier was built, the solution to flooding was to build higher and stronger river walls and embankments — a solution that became popular following the Thames Flood Act of and remained an accepted measure until midway through into the 20th century. Following a report in by Sir Herman Bondi, it was decided that the best solution was bank raising and a flood barrier with movable gates built across the Thames.

The Thames Barrier and Flood Protection Act gave powers to carry out this solution and led to the construction of the barrier. The barrier was originally designed to protect London from a very large flood 1 in years up to As climate change and rising sea levels are creating a higher risk of flooding in London, improvements to the Thames Barrier and its flood management are needed to keep on protecting London from flooding. In the Thames Estuary project headed by Dave Wardle was set up.

It is a cross-regional Environment Agency project with the aim of developing a strategic flood risk management plan for London and the Thames estuary through to The final plan will recommend what flood risk management measures will be required in the estuary, where they will be needed, and when over the coming century, based upon the climate change and sea level rise scenarios.

The Thames Barrier is not the only structure designed to protect London from flooding that will be improved in the Thames Estuary Project.

In addition to these, the tidal Thames has 36 major industrial floodgates and smaller moveable structures — mostly protecting residential property. Read more about flood risk in the UK. You are commenting using your WordPress. You are commenting using your Google account. You are commenting using your Twitter account. When it shut in December , it was reported to be the first closure since March The barrier, made up of 10 steel gates, reaches m 1,ft across the river.

When open, the gates lie flat on the river floor and close by being rotated upwards until they block the river. The four main gates span The barrier is closed just after low tide to create an empty "reservoir" for the river flow to fill up.

It takes minutes to close it, starting with the gates on the outside until the middle gates are shut. With no barrier, at high tide, the sea would normally flow up the estuary and into London, pushing the river water back. With all the extra rainfall, this could worsen the flooding. The barrier prevents this from happening.

The gates are left shut and the river water is held until the tide turns. Staff wait for the water on both sides to "equalise" - reach the same level - and then the gate is opened and the river water can rush out into the estuary. There is no danger that the water will overwhelm the barrier. Storm surge from the North Sea, high tides and exceptional fluvial river flow are the three factors that make it necessary. At the moment the major factor is the amount of water flowing down the Thames.

That impact is felt up the Thames as far as Molesey - about 12 miles from central London. For more information, see the below animation. When construction on the barrier began in , the idea of a barrier or dam across the River Thames to protect the population of London from flooding had already been discussed for several decades. The first impetus for modern flood-control defenses along the River Thames came after the disastrous flood of January , which killed fourteen and left thousands homeless in central London.

A committee who reviewed the floods recommended that investigations into the possibility of a barrier be undertaken. The Thames Barrier Act was finally passed in David Iliff Click here to view Wikimedia source.

With each of the main gates being just over 20 meters high and able to cope with a tidal surge of nearly 10 meters above normal, the Barrier was built to protect London from a 1-in year flood-level.

However, due to changing tidal levels and the slow subsistence of the south-east of England post-glacial rebound , as predicted during initial planning, the Barrier has had to be raised with increasing frequency. With sea levels predicted to rise further due to anthropogenic climate change and with rising population density in London, it seems likely that the barrier will be increasingly called into action until it is due to be replaced around Hall, Alexander.

Rachel Carson Center for Environment and Society. Please click on the images to view their individual rights status. Skip to main content. Arcadia Collection: Water Histories. River Thames in Flood near Marlow. Photo by Paul Farmer.