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  • This episode of Real Engineering was brought to you by Skillshare, home to over 16,000

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  • On a cold and stormy morning in January 1953, the Princess Victoria ferry was preparing

  • to leave its dock in Stranraer on the south-west coast of Scotland, despite gale warnings.

  • An hour into its journey its captain radioed for help as the storm forced the ferry on

  • its side, making it impossible to board the lifeboats.

  • Of the 176 people aboard the princess victoria, only 43 survived, but there was more tragedy

  • to come, this storm was headed south towards the Netherlands, pushing the seas with it,

  • and with the Moon and Sun causing even higher tides, this storm would severely test the

  • flood defences of the Netherlands, which was still getting back on its feet after the Second

  • World War.

  • The storm would ultimately claim the lives of 1,835 people in the Netherlands, along

  • with 200,000 cattle and flooding 2,000 square kilometres of land, destroying 43,000 homes

  • forcing and 72,000 people to flee.

  • Today, we are going to learn why this happened and how it would spark the construction of

  • one of the seven modern wonders of the world: The Dutch Delta Works.

  • After World War 2, the meandering levees on the coast of the Netherlands had fallen into

  • disrepair, the Netherlands were just getting back onto their feet after 5 years German

  • occupation just 8 years prior to the storm.

  • The poorly maintained flood defences were a disaster waiting to happen.

  • As the storm approached, it forced water inlands with no-where to go, but up.

  • This put intense pressure on the dykes and levees of the low countries, and by the storm's

  • end 139 kilometres of levees would be heavily damaged, with holes up to 3.5 kilometres being

  • torn open.

  • With nearly 26% of the Netherlands land area being under sea level, seawater burst through

  • these breeches with immense strength causing damage that would take decades to repair and

  • would spur the formation of the Delta Committee just 20 days later to ensure this could never

  • happen again and this is what they came up with.

  • The new Delta plan would shorten the Dutch coastline by 700 kilometres, by closing the

  • primary inlets in these 4 locations, this would drastically reduce the length of levees

  • and dykes that needed to be inspected and maintained and thus decreasing the chances

  • of weak points jeopardising the safety of the Dutch people.

  • However this was no easy task and would come with an enormous cost.

  • Before these works could be completed, additional barriers needed to be erected upstream to

  • improve fresh and saltwater management, and prevent fresh water emptying from the Rhine,

  • Meuse and Schelde river from redirecting around these new dams.

  • The northern most closure dam also needed to be equipped with a hydraulic sluice capable

  • of dealing with the output of the Rhine river, as this Fresh water would flood the Netherlands

  • from the other direction, if it was prevented from emptying into the North Sea.

  • On top of all this, a number of ports, such as the port of Rotterdam and the port of Antwerp,

  • had to stay accessible.

  • So, aside from fixed dams, bridges and sluices, two new locks that would allow an inland ship

  • route between Antwerp and Rotterdam needed to be built.

  • Amazingly, on top of all this work, the dutch still managed to consider the environmental

  • impact of this work.

  • The largest of the structures built for the Delta Works project, the Oosterschelde Storm

  • Surge Barrier, was originally planned to completely close the mouth of this river, which would

  • create a fresh water basin.

  • However resistance to this plan arose, as it would completely change the saltwater environment

  • of the area.

  • The Oosterschelde scenery is unique, with a great variety of fish, water plants and

  • animals.

  • So in 1976 the Dutch government agreed to a different plan: Building an open barrier

  • that could be closed during heavy storms and high tides.

  • adding another 2.5 billion euros to the cost to the project.

  • This barrier is 9 kilometres long with 62 openings, each 40 metres wide, allowing the

  • tidal movement to remain in tact.

  • To build a structure this massive, that needs to not only support it's own weight, but

  • the enormous force of a storm surge pushing against it, would require extensive foundations.

  • The first part of these foundations were created by forming two islands, the biggest of which

  • housing a lock to allowing ships to pass through the barrier.

  • This island even included a massive dry dock to construct the 65 pylons needed to support

  • the sluice gates, each using 7,000 cubic metres of concrete and taking one-and-a-half years

  • to build.

  • Between each island a trench was dug.

  • On both sides of the trench, mats were placed to keep the seabed in place.

  • While specially built ships were then used to consolidate the sand at the bottom of the

  • trench, using special vibrating needles, the sand would be vibrated to pack the sand firmly

  • together creating a surface that could carry the weight of the massive pylons.

  • The trench itself was then covered with specially made mats filled with rocks to help prevent

  • erosion of the underlying sand.

  • The pylons were left hollow so they could be picked up by another purpose-built, u-shaped

  • ship, and moved into place.

  • There, inside the trench, on top of the mats, they would be lowered, filled with sand and

  • closed with concrete.

  • The wide foot of each pylon was packed in stone, as it is vital the pylons never move,

  • because if even one of the massive, 260 to 480 tonne doors, cannot move, the current

  • in that location could become enormous and potentially damage the structure.

  • Finally these enormous hydraulic pistons were attached to the sluice gates, allowing 3 kilometres

  • of the 9 kilometre long Storm Surge Barrier to open and close on demand.

  • This project truly is one of the modern wonders of the world.

  • Allowing the dutch to rule the tide and ensure the chances of another devastating flood are

  • dramatically reduced, but with sea levels continuing to rise and warmers seas causing

  • even stronger storms, we need to remind ourselves of the lessons learned here.

  • The flooding of New Orleans in 2005 occurred for many of the same reasons as the 1953 flooding

  • of the Netherlands.

  • Poorly maintained levees broke well below their design tolerances, allowing 80% of the

  • city to be flooded in just 5 hours.

  • Had New Orleans taken lessons from history and reduced the length of defences needed,

  • as they have done now with the 1.1 billion dollar Lake Borgne Surge Barrier, they may

  • have saved of over 1000 people and prevented the 108 billion dollars of damage the storm

  • caused.

  • If these trends continue cities around the world are going to have to seriously assess

  • the risk of flooding and make plans to prevent any chance of a flood taking the lives of

  • their citizens.

  • So you may admired some of the footage in this video, it's not the first I have travelled

  • to a location to get footage, but it is the first time I have really felt prepared because

  • I finally learned the necessary skills to use my equipment like a professional from

  • Skillshare.

  • I learned all the technical terms and settings to set up still shots of the storm surge barrier.

  • I learned how to get cinematic shots with my drone and I learned how to apply the correct

  • colour corrections too.

  • Skillshare is simply the best place on the internet to learn creative skills that could

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  • So ask yourself right now.

  • What skill have you been putting off learning.

  • What project have you been dreaming of completing, but you aren't sure if you have the skills

  • to do it.

  • Why not start right now and sign up to Skillshare using the link below.

  • You have nothing to lose and a valuable life skill to gain.

  • As usual, thank you for watching and thank you to all my patreon supporters for helping

  • this channel exist.

  • If you would like to see more from me or see more content from Real Engineering, like sneak

  • peeks for upcoming videos, check out the links for Instagram, twitter and facebook accounts

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オランダが水没しない理由 (Why The Netherlands Isn't Under Water)

  • 11 0
    Courtney Shih に公開 2021 年 01 月 14 日
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