Silvery Shells
The Sydney Opera House nests its shells into a stunning piece of architecture - the Thames Barrier keeps them separate (and identical) and much more mundane.
The Thames Barrier spans 520m across the River Thames near Woolwich, and it protects 125 square kilometres of central London from flooding caused by tidal surges. It has 10 steel gates that can be raised into position across the River Thames. When raised, the main gates stand as high as a five-storey building and as wide as the opening of Tower Bridge. Each main gate weighs 3,300 tonnes.
The barrier is closed under storm surge conditions to protect London from flooding from the sea. It may also be closed during periods of high flow over Teddington Weir to reduce the risk of river flooding in some areas of west London including Richmond and Twickenham.
The Thames Barrier will then remain closed over high water until the water level downstream of the Thames Barrier has reduced to the same level as upstream. This is a managed process to provide for different circumstances, and takes about five hours. The Thames Barrier is then opened, allowing the water upstream to flow out to sea with the outward-bound tide.
The Environment Agency has closed the Thames Barrier 174 times since it became operational in 1982 (as of July 2014). Of these closures, 87 were to protect against tidal flooding and 87 were to alleviate river flooding. The frequency of closures has increased over recent decades:
In the 1980s there were 4 closures
In the 1990s there were 35 closures
In the 2000s there were 75 closures
In the 2010s there were 65 closures (as of July 2014)
The barrier is currently expected to be in service until at least 2030, and possibly as far into the future as 2070, although scientists and academics are already suggesting that a replacement needs construction now.
Seen at low tide on a sunny October morning.
Silvery Shells
The Sydney Opera House nests its shells into a stunning piece of architecture - the Thames Barrier keeps them separate (and identical) and much more mundane.
The Thames Barrier spans 520m across the River Thames near Woolwich, and it protects 125 square kilometres of central London from flooding caused by tidal surges. It has 10 steel gates that can be raised into position across the River Thames. When raised, the main gates stand as high as a five-storey building and as wide as the opening of Tower Bridge. Each main gate weighs 3,300 tonnes.
The barrier is closed under storm surge conditions to protect London from flooding from the sea. It may also be closed during periods of high flow over Teddington Weir to reduce the risk of river flooding in some areas of west London including Richmond and Twickenham.
The Thames Barrier will then remain closed over high water until the water level downstream of the Thames Barrier has reduced to the same level as upstream. This is a managed process to provide for different circumstances, and takes about five hours. The Thames Barrier is then opened, allowing the water upstream to flow out to sea with the outward-bound tide.
The Environment Agency has closed the Thames Barrier 174 times since it became operational in 1982 (as of July 2014). Of these closures, 87 were to protect against tidal flooding and 87 were to alleviate river flooding. The frequency of closures has increased over recent decades:
In the 1980s there were 4 closures
In the 1990s there were 35 closures
In the 2000s there were 75 closures
In the 2010s there were 65 closures (as of July 2014)
The barrier is currently expected to be in service until at least 2030, and possibly as far into the future as 2070, although scientists and academics are already suggesting that a replacement needs construction now.
Seen at low tide on a sunny October morning.