The Barrier made up of 10 steel gates, reaches 520m (1,700ft) 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 61.5m (200ft) and weigh more than 3,000 tonnes each. The barrier is closed just after low tide to create an empty “reservoir� for the river flow to fill up. It takes 75-90 minutes to close it, starting with the gates on the outside until the middle gates
A flood
occurs
when water overflows or inundates land that’s normally dry. This can happen in a multitude of ways. Most common is when rivers or streams overflow their banks. Excessive rain, a ruptured dam or levee, rapid ice melting in the mountains, or even an unfortunately placed beaver dam can overwhelm a river and send it spreading over the adjacent land, called a floodplain. Coastal flooding occurs when a large storm or tsunami causes the sea to surge inland. Most floods take hours or even days to develop, giving residents ample time to prepare or evacuate. Others generate quickly and with little warning. These flash floods can be extremely dangerous, instantly turning a babbling brook into a thundering wall of water and sweeping everything in its path downstream. Disaster experts classify floods according to their likelihood of occurring in a given time period. A hundred-year flood, for example, is an extremely large, destructive event that would theoretically be expected to happen only once every century. But this is a theoretical number. In reality, this classification means there is a one-percent chance that such a flood could happen in any given year. Over recent decades, possibly due to global climate change, hundred-year floods have been occurring worldwide with frightening regularity. Clean-up activities following floods often
pose hazards to workers and volunteers involved in the effort. Potential dangers include electrical hazards, carbon monoxide exposure, musculoskeletal hazards, heat or cold stress, motor vehicle-related dangers, fire, drowning, and exposure to hazardous materials. Because flooded disaster sites are unstable, clean-up workers might encounter sharp jagged debris, biological hazards in the flood water, exposed electrical lines, blood or other body fluids, and animal and human remains. disasters, managers provide work-
Key facts: Drowning is the 3rd leading cause of unintentional injury death worldwide, accounting for 7% of all injury-related deaths. There are an estimated 372 000 annual
drowning deaths worldwide. Global estimates may significantly underestimate the actual public health problem related to drowning. Children, males and individuals with increased access to water are most at risk of drowning.
during its existence include flood damage to work from the River Thames, and bomb damage during World War II. However, most of the collection was in safe storage elsewhere during the war, and a large Stanley Spencer painting, deemed too big to move, had a protective brick wall built in front of it.
No doubt
we’ve all heard of the legend of Atlantis, the ancient, once great city that was lost when the ocean submerged it. To this day the legendary city has yet to be found (or proven to have ever existed) yet over the years many other underwater cities have been found, each of them as eerie as they are mind blowing. Just off the shores of Alexandria lies what is believed to be the palace of Cleopatra, an ancient Egyptian queen. It is believed that the ruins were cast into the sea by an earthquake over 1,500 years ago and lay dormant until recent years. Along with the royal quarters, archaeologists also believe they have found the temple of Isis alongside them. To date, more than 140 artifacts have been uncovered from the site and experts now believe they have located the tomb of Cleoplatra and an ancient museum within the ruins. Hopefully the ruins will be opened up to divers and tourists in the years to come, allowing us all to have a closer look at the marvel that is Cleopatra’s palace. Sucked into the sea by earthquakes or intentionally flooded to create dams, ancient and contemporary cities lurk just beneath the surface in bodies of water all over the world. Some, like Alexandria in Egypt, represent some of the most significant archaeological findings in
recent history; others are more mysterious in origin. The eerie remains of these 7 submerged cities will reveal their secrets only to those who can swim through their underwater streets in scuba suits. Believed to have been submerged off the coast of Greece by a series of earthquakes around 1,000 BCE, Pavlopetri is the oldest-known underwater archaeological town site in the world.
Storm surges in themselves are rare and, on their own, pose little threat to the city of London. However, if global warming continues to affect sea levels, this threat will be increased. Additionally, supposing sea levels have significantly risen, if a storm surge hits at high tide, and only at high tide, it could prove to be disastrous to the capital.
But if only one of these three variables is missing, flooding is very unlikely. This page explains how these factors work together. Most storm surges experienced by the UK originate around the east coast of Canada and travel across across the Atlantic Ocean unnoticed. But occasionally a northerly wind will blow the hump into the North Sea. their way inland along the river.
A Japanese construction company has put forward its proposal to solve the issue of rising property prices – start building cities in the ocean. The famously ambition Shimizu Corporation has unveiled its template for a modern-day Atlantis, a self-sufficient community that sits on or just under the surface of the sea. The Ocean Spiral project envisages using huge spirals to connect each watertight residential sphere to the ocean floor, where it would create power in the form of methane-producing micro-organism factories. Other rare earth materials could also be mined from the seabed, and transportation to get down there would come in the form of spheres travelling along the length of the spiral.
People – as many as 5,000 –
would live in a sealed transparent ball at the top of the spiral. It would generally sit above the surface to take advantage of sunlight, but could be retracted under the waves in the event of bad weather.
S
High Tide
rope is estimated at 2,551.
By the time it reached the Thames it had fallen to 2.59 metres, though the funnel shape of the river is likely to have caused the height to increase as the surge travelled inland. The docklands were flooded but, luckily, the rest of the city remained dry. 307 people were killed on land in the UK, 30,000 were evacuated, and 24,000 lost their homes. The total death toll across Eu-
Clean-up activities following floods often pose hazards to workers and volunteers involved in the effort. Potential dangers include electrical hazards, carbon monoxide exposure, musculoskeletal hazards, heat or cold stress, motor vehicle-related dangers, fire, drowning, and exposure to hazardous materials. Because flooded disaster sites are unstable, clean-up workers might encounter sharp jagged debris, biological hazards in the flood water, exposed electrical lines, blood or other body fluids, and animal and human remains. In planning for and reacting to flood disasters, managers provide workers with hard hats, goggles, heavy work gloves, life jackets, and watertight boots with steel toes and insoles
torm surges alone can cause the city damage. The storm surge of 1953, known as the North Sea Flood, occurred before the Thames Barrier was erected and was the primary cause for its construction. On the night of the 31st of January a tidal surge measuring 5.60 metres swept down the coast of England.
Europe is at the forefront of the flood control technology, with low-lying countries such as the Netherlands and Belgium developing techniques that can serve as examples to other countries facing similar problems. After Hurricane Katrina, the US state of Louisiana sent politicians to the Nether-
lands to take a tour of the complex and highly developed flood control system in place in the Netherlands. With a BBC article quoting experts as saying 70 percent more people will live in delta cities by 2050, the number of people impacted by a rise in sea level will greatly increase.The Netherlands has one of the best flood control systems in the world and new ways to
THE FUTURE
Flood barriers In recent years the Environment Agency has used a range of temporary or “demountable� flood barriers to provide additional protection to flood-prone areas. Lightweight sectional metal barriers are relatively inexpensive and can be placed in various configurations and removed completely when waters recede.
Frame barriers consist of rigid frames holding an impermeable membrane and use the weight of the floodwater itself to hold .
Graphic: Two types of flood barrier
fence features include small barriers in ditches and fields, or notches cut into embankments, all of which divert the water into open land.
Natural flood management Natural flood management offers a sustainable approach to managing floods and is intended to complement traditional “hard engineering� techniques, such as flood barrier and concrete walls.
Natural flood de-
Letting pools form outside the main channel of the river means the water is temporarily removed from the main flow reducing the power of the floodwaters. Tide gates are used in conjunction with dykes and culverts. They can be placed at the mouth of streams or small rivers, where an estuary begins or where tributary streams, or drainage ditches connect to sloughs. Tide gates close during incoming tides to prevent
IS THIS
THE END?