CALM INSTRUMENTAL MUSIC
MAN:
The Afsluitdijk is levelling up.
This Dutch icon of hydraulic engineering...
is getting a well-deserved upgrade, the first major one in 90 years.
Time to take a look at what we're doing to make sure that The Dike that Closes Off...
never shuts down.
You're watching Waterworks...
a series of educational videos about the Afsluitdijk...
in which we take a closer look at this beloved dam.
Despite the fact that the Dutch name refers to it as a dike...
it is actually a dam, which closes off parts of the sea surrounding the Netherlands.
In this video, we'll focus on the custom-made technical marvel...
that will protect the Dutch landscape for the next 100 years...
Levvel-blocs.
We'll also talk about superstorms, titans, ballerinas...
and the mother of all testing grounds: the Delta Flume.
So let's go.
In the Netherlands, we've always been at the forefront of hydraulic engineering.
We plan for the worst, but hope for the best.
And when 60% of your country is vulnerable to flooding...
high standards and requirements for protective measures...
are something you take very seriously.
Superstorm seriously.
We set our standards to withstand...
a mix of circumstances that only occur once every 10,000 years.
A superstorm that would sweep away...
all the old basalt blocks that used...
to cover the Afsluitdijk like pebbles.
But don't worry.
A storm of this magnitude has never happened.
Yet.
These standards, coupled with a slight decay...
of the existing dam elements and the uncertainty...
of climate change, were the reasons...
why experts called for the first major upgrade since 1932.
That's right.
The Afsluitdijk has gone an entire lifetime...
without heavy maintenance, even withstanding the 1953 flood disaster...
an impressive feat.
The new and improved Afsluitdijk...
will protect against rising sea levels until at least 2050...
which is based on current climate change estimates...
of a sea level rise of 0.35 meters by that time.
Some parts are even built to last 100 years...
like the revetment.
By implementing smart measures now...
it will be possible to further reinforce...
the dam in the future with relatively simple interventions.
This is called Adaptive Delta Management.
Like we said: Hope for the best, plan for the worst.
As you all know, a sound technical design...
is the most important aspect.
But we also want to protect the adjacent UNESCO nature reserves in the Waddenzee.
This means expanding the circumference of the dam...
as little as possible, while also minimizing the CO2...
impact of production materials and transport.
We have a saying in the Netherlands that literally...
translates to: the eye also wants something.
We honor that saying by preserving the classic Afsluitdijk look of spectacular simplicity...
and thereby preserving a piece of Dutch history.
Protection and preservation.
These are two words that we returned to again and again.
These requirements together resulted in this design.
Now, we know engineers love getting technical.
So let's dive in.
RHYTHMIC MUSIC
We start our tour at the toe of the dam...
which was built with rocks up to 2,000 kilograms.
On the lower slope, we used something...
called Levvel-blocs, which are huge plus-shaped blocks.
And we'll talk more about those later.
And finally, an asphalt berm on the storm water level...
to reduce wave overtopping...
which also serves as one of the most beautiful bicycle...
paths in the Netherlands, with a spectacular view...
of the Waddenzee.
The upper slope of the dam will be protected by different blocks...
that are known as Quattroblocks...
which consist of four distinct blocks that form a basalt-like texture...
when connected together. As you know...
rough surfaces break waves much better...
thereby reducing wave overtopping.
Basalt isn't a rough surface however...
but there's nothing a little Dutch ingenuity can't fix.
You see those ribs in the dam's surface?
Those are high and low Quattroblocks mixed together.
This way its looks resemble the classic Afsluitdijk...
but it breaks waves like a modern powerhouse.
Now, let's talk about Levvel-blocs.
We developed these blocks, especially for the Afsluitdijk.
As you can see they roughly resemble a plus shape.
Placed next to each other they create a surface that is rough and porous enough to dissipate wave action...
while keeping the spectacular simplicity of the original Afsluitdijk look.
The plus-shape offers great stability while using much less concrete than its...
predecessors, the Xbloc and the Ybloc.
Also it looks like a work of art when stacked together, and we stacked...
a lot of them together.
How many?
70,000 Levvel-blocs in total...
each about a meter high and 6,500 kilograms in weight.
That's 487 million kilograms in total.
See this large hole? It serves two purposes.
During construction a clamp inside the hole helps cranes to lift them up.
This is a big help for a block that weighs as much as an elephant.
Once in place, the hole also allows for efficient water drainage...
thereby reducing the uplift pressure during an extreme wave attack.
The Levvel-blocs were created especially for the Afsluitdijk...
but will live on under a different name, the XblocPlus.
We can already see an example of its protective qualities on Vistula Spit in Poland.
On the inner slope and the crown...
we flexed some centuries-old hydraulic muscles with a tough clay layer...
topped with grass. Both are excellent water barriers.
These layers form an effective water barrier to protect the inner slope from...
erosive damage caused by overtopping waves.
But a great design is worthless if it doesn't work.
So we tested a lot.
Someone who knows everything about testing is Bas Reedijk.
Bas, how exactly do you test a dam?
PEACEFUL MUSIC
We started with computer modelling, but when designing for a 45 hour superstorm...
with significant wave heights of over four meter and water level of more than...
five meters above mean sea level, then real life tests are essential.
This is firstly done by physical model testing in small scale wave flumes at a...
1 to 30 scale and then again and again...
testing it and perfecting it a little bit more every time.
After that it was time for the mother of all wave flumes, a 300 meter long channel...
five meters wide, nine and a half meter deep giant that's called The Delta Flume.
It's the largest of its kind in the world and it's located on the grounds of...
The National Hydraulic Laboratory in Delft.
The Delta Flume holds 9 million liters of water and can create life-size waves.
It's even capable of generating the superstorm waves we talked about at the...
start of the video on the one to three scale.
the Levvel-blocs passed with flying colours.
Just to show off, we even tested the blocks at twice the power of superstorm waves.
They didn't budge.
When it was time to actually install them on the Afsluitdijk...
the team used a huge crane called the Titan which was specifically designed for the job.
Quite a contrast from the crane that placed the Quattroblocks, which is called the Ballerina.
So safety? Check. Looks? Check. Nature? Ofcourse we didn't forget about nature. The shape of the...
Levvel-bloc, for instance, is rugged, which creates holes and cavities when the blocks are placed...
side by side in addition to the big hole in the center of the block. These cavities are great for...
algae, plants and shellfish, among others. They essentially become an artificial reef...
creating a surface for all kinds of creatures, plants and other underwater life forms. A large strip of...
grass and flowers will also form a bee-highway adding to our collection of animal infrastructure...
solutions like the Fish Migration River. Our emission reduction goals were met as well.
The shape of the Levvel-bloc, the optimized production and transport process...
helps to reduce CO2 emissions by 55% compared to conventional armour, production and transport methods.
All these aspects together make up the literal and figurative building blocks of the Afsluitdijk.
Want to know more? Watch our other videos. For now we'll see you next tide.
CALM INSTRUMENTAL MUSIC