All language subtitles for Impossible Engineering s09e02 Worlds Greatest Waterworks.eng

In this episode...

This is the largest water
transfer project in the world!

...an engineering megaproject

that's sending water
across China

to where
it's desperately needed.

I think it's really amazing
that all this water

slowly goes under
this huge yellow river.

And the groundbreaking
innovations from the past...

Wow. That is a long way up.

It's quite hard unless you know
what you're doing,

and I'd imagine things
can go wrong very easily.

...that make the
impossible possible.

Captions by vitac...
www.vitac.com

captions paid for by
discovery communications

Beijing, China, is one
of the world's largest cities,

home to over 21 million people.

But beneath the surface,
there's a problem.

This giant city is seriously
lacking in drinking water.

Beijing is actually

one of the most water-scarce
cities on the planet.

The groundwater is so depleted,

it's actually causing
subsidence.

In some areas of the city,

the earth is actually
starting to collapse.

Rainfall in the city has been
decreasing since the 1950s,

and the problem
is only going to get worse.

The south of China has a much
higher rainfall than the north,

so could it be possible
to transport water

across the country
from the south to the north?

Moving enormous
quantities of water

across one of the world's
biggest countries

seems impossible.

But engineers have come up with
something truly spectacular.

The south-to-north
water diversion project

is the largest
and most ambitious in the world.

Once complete, the entire
network will be

over 2,700 miles long,

more than the distance
between New York and L.A.

Three routes... eastern,
western, and central...

Will connect rivers from the
south of China to the north

and transfer over 11 trillion
gallons of water each year.

Of the three routes,
the eastern has been completed,

and the western
has yet to be started,

but the central
is the most challenging.

On the central route,

the water must flow
over 870 miles

entirely by gravity,
with no pumps.

At the start,
the Danjiangkou reservoir

will store over
7 trillion gallons of water.

The 5.5-mile-long
Shahe aqueduct

will transport the water
at 100,000 gallons per second.

It will then travel
under the yellow river

and arrive
15 days later in Beijing.

China's water diversion project
is so massive,

it takes days to drive
from one end to another.

I'm following a central route
from Danjiangkou to Beijing.

New York-based
architect Wendy Fok

is traveling from
the south to the north

to see how this
seemingly impossible project

is being built.

It's such a huge challenge.

How do you move water

thousands of kilometers
across a whole country?

How do you cross
mountains, rivers, valleys,

and all these types of terrain
and keep water flowing downhill?

How do you manage the flow of
water over such large distances?

Wendy's journey along
the central route

starts in the south

at one of the largest
manmade lakes in China,

the Danjiangkou reservoir.

It's beautiful here.

The water here will travel over
850 miles north to Beijing.

Every drop of this water
in this reservoir

is going to be heading north,

so in order to contain
this much water,

you need a very big dam.

The original dam has
been here since the 1950s,

but it's not big enough
for this project.

When this dam became part

of the south-north
water diversion project,

more water had to be contained.

So to do this, they had to raise
the dam by 15 meters.

Raising a dam is not easy.

Old concrete and new concrete
are not easy to join.

And the dam's location
raises the stakes even higher.

There's approximately
700,000 people that live here,

so it's vital for the engineers

to make sure that a dam
does not break.

To find a solution
to raise the dam safely,

engineers had to look
to the past.

I'm really excited to see this.

This place is part
of engineering history.

Engineer Dan Dickrell is in

the Sierra Nevada mountains
in California

to check out a construction

that could help inspire
the engineers in China.

Wow!

This is the O'Shaughnessy dam.

It's 430 feet tall
and 900 feet long.

When it was completed,

it was the second-biggest dam
in the world.

Wow!

What an amazing view.

But the dam
wasn't always this high.

The original dam, built in 1923,

created the
Hetch Hetchy reservoir,

which provided water to
the residents of San Francisco.

But within a year,
the project hit a snag.

More water was required,

which needed the reservoir
to become bigger.

The only way to do that
was to raise the dam.

Wow. This is actually
quite impressive.

I'm lucky to have access
to this space.

Only people that maintain this
dam are allowed in this place.

The problem with
raising a dam is,

you have to put new concrete
on top of old concrete.

Trying to get it
to bind together,

there's a problem,
because the new concrete

will shrink as it cures, as the
water leaves that mixture.

That shrinkage can cause stress

in between the old concrete
and the new concrete,

creating a poor bond.

A second issue... a larger dam
allows more water to be stored,

but the pressure of that water
behind this dam,

trying to force its way out,
toppling the dam...

Those forces are tremendous.

At the time, no dam
had ever been raised 85 feet,

but water engineer
Michael O'Shaughnessy

was determined to build
a revolutionary dam

that could achieve
the impossible.

The original dam he built
was 345 feet tall.

And that was big,
but he was a smart guy

and he realized it might need
to be bigger in the future.

His design needed
to be adaptable.

So, O'Shaughnessy came up with
a pioneering design adaptation

to his original dam that allowed
it to be raised in the future.

O'Shaughnessy included a series
of five-foot steps on the dam.

What this did is it
increased the surface area,

and I'm able to bond

between the old concrete
and the new concrete

to be as strong as possible.

Building a series of giant
steps on the original dam

dramatically increased
the surface area,

helping the new concrete
to stick.

Engineers took O'Shaughnessy's
trick of increasing adhesion

one step further

by scoring and notching
the surface of the concrete,

allowing for a tighter bond

between the
new and the old material.

The result is an incredible
feat of engineering.

The overall reservoir capacity
increased by 75 percent,

to an overall volume of over
530 billion liters of water.

More than 80 years
after the raising of the dam,

it still provides water
to the 2.5 million citizens

of the San Francisco area.

The Danjiangkou dam
in south China

is 12 times longer
than the O'Shaughnessy dam,

but engineers have still
been able to raise it

by almost 50 feet.

This is one of the
longest dams I've ever seen.

This dam is huge,
and you could really see

the new and the old dam
being joined together.

It is so big that
the whole thing

actually feels like
it's wrapping all around us.

It's amazing.

And with the sun setting,
it's beautiful.

Joining the old
and new concrete together

was the dam engineers'
biggest challenge.

And like the
O'Shaughnessy dam in California,

the secret was to increase
the bonding area.

First, the existing concrete
is blasted

to make thousands of grooves,

which, like the steps
on the dam in California,

increase the size
of the surface.

Then, thousands of steel rods
are drilled into the dam

to help anchor the new concrete
as it's poured on top.

It took four years for the dam

to reach its new height
of over 577 feet.

But increasing the volume
of water in the reservoir

by more than 3 trillion gallons
creates a new challenge.

With too much water pressure,

the bottom of the dam
would erode away

and the dam itself
would tip over.

So to solve
the high water pressure

and the base of the dam
from eroding,

engineers had to install
a huge grout curtain

on the base of the dam.

A grout curtain
prevents the weight of water

from seeping underneath
the dam's base.

Waterproof grout is injected
beneath the dam,

forming a giant underground
wall, or curtain, 213 feet deep

that holds the soil
under the dam in place.

The engineers succeeded
in raising the dam

and filling the reservoir.

But this is just the beginning.

The water now has an
870-mile-long journey north

through some of the country's
most challenging terrain.

So digging a very long,
very deep tunnel

in this very soft ground
is a huge engineering challenge.

China's south-to-north
water diversion project

will use three routes

to draw water from
the country's southern rivers

and supply it to the
drier cities in the north.

The project's central route

begins at the giant
Danjiangkou dam.

From here, water will flow
entirely by gravity

along aqueducts and
open channels

870 miles north to Beijing.

And the water needs
to keep flowing

no matter what lies in its path.

155 miles north of the dam

is one of the most challenging
terrains on the route...

The Shahe river.

The region's heavy rainfall
and swollen rivers

can cause havoc.

This is the Shahe river.

Usually in the rainy season,
this is all filled with water.

The ground is really soft,
so it's often flooded.

"Shahe" also means
"sandy river."

Seasonal flooding will
breach the channels

of the diversion project.

Open channels would not work in
terrains like this,

so engineers had to devise
a new way to move the water.

Could the solution be found
thousands of years in the past?

Archeologist Jens Koehler
is in Rome, Italy,

seeing how this ancient city
met its need for water.

For the first 400 years
of Rome's history,

the city relied on water supply
from the Tiber river

and from groundwater Wells.

The city was growing,

and these people needed
not only space, but water.

There was plenty of water
in the Apennine mountains,

62 miles away.

The Romans just needed
to find a way to move it.

Roman author Vitruvius

wrote about civil engineering
and architecture.

His work on transporting water

was an essential influence
for Roman engineers.

Incredibly, what they achieved
2,000 years ago

is still visible today.

This is the solution
of Rome's water problems...

The Roman aqueducts.

Rome had 11 of these aqueducts.

These enormous structures

are up to 56 miles long
and 108 feet high.

Water comes from the mountains

and flows in the water channel
towards the city.

One of the oldest aqueducts
is the aqua Marcia.

One can still look
into the water channel.

The water level
was about two feet high.

This may be one-third
or half of this,

but the Roman water
is very hard.

It's full of minerals.

And you see this here,

it accumulated up to something
like 20 centimeters.

The Romans also
devised a way to prevent leaks.

This is plaster

mixed with crushed tiles
and crushed pottery.

So something what
protects water from penetrating.

We know that they probably
mixed olive oil in

to make it
even more water-resistant.

Roman engineers started building

more and more ambitious
aqueducts.

Aqua Claudia is 43 miles long
and over 98 feet high.

Completed around 47 A.D.,
it took six years to build.

This is one of the best parts
of the aqua Claudia.

More than 100 arches
of massive stone

are preserved here.

Like the engineers in China,

the Romans had to
transport water

across challenging terrain,
using only gravity

to keep the water
flowing at just the right speed.

Vitruvius recommends
as a gradient 0.02 percent...

20 centimeters on a distance of
one kilometer...

Because fast-running water
causes turbulences

and could damage
the aqueduct channel,

and fast water streams
transport all impurities...

Pebbles, sand, everything.

Did you want to have this
in your final fountains in Rome,

in your drinking water?

No.

To keep the gradient correct,

Vitruvius describes a leveling
device called a chorobates.

You see the plumb lines,

and yes, they are both
out of level.

Water can be used
to check the slope.

I have more water on my right
and less on the left.

Let me try to level this.

Once the chorobates is level,

it's possible to continue
the straight line

to the next arch position,

using the sights and marking it
on a vertical pole.

Down with the finger.

Down.

A little bit up.

And here we are.

Once they knew where level was,

the Roman engineers
could build their aqueducts

with the correct gradient.

To decide the gradient, now
we have to take off something.

For example, a centimeter
or only a half,

depending on the distance.

The same process could be
repeated, one arch at a time,

the entire length
of the aqueduct.

Using simple tools,
the Romans built vast aqueducts

at precise gradients

with an accuracy
almost equal to modern devices.

It meant nearly
300 million gallons of water

reached Rome every day,

the same as New York City today.

We are at Fontana di Trevi,

beautiful fountain
that is still fed by water

through an ancient aqueduct.

We can learn
from Roman aqueducts.

Their simple but efficient
construction may help us

to resolve several
water transport problems today.

Back at the
Shahe river in China,

engineers will need to use
this same ancient ingenuity

as they attempt to build the
largest aqueduct in the world.

Inspired by the ancient Romans,
the Chinese are building

the largest aqueduct in the
world at the Shahe river

as part of their south-north
water diversion project.

At over 1,300 tons, each section
is too big to transport.

Instead, they are constructed
on-site using giant molds.

So, right now, we're in front

of the biggest mold
that makes the aqueducts.

It is about 7 meters by 9 meters
and 40 meters in length.

It's the fastest in-situ,
concrete-poured mold in China.

The sections
can be built quickly,

but they need to be
strong enough

to withstand
the forces of the water.

The shape of the mold
is super important.

When water flows through it,
if it were a square,

all the forces would be on the
stress points on the corners.

However, in this case
it is a "U"

so that forces are evenly
distributed onto the sides.

With the giant
u-shaped sections in place,

the enormous aqueduct
can be filled.

The Shahe aqueduct carries over
80,000 gallons of water a second

across China's
challenging terrain.

Like the Roman aqueducts,

it's constructed at a precise
slope of .02 percent

so the water can run
along its length.

Site operator Li Zhi
manages the flow.

We set meters along the route

to monitor the change
of the flow rates

and the volume of the water
at any time.

We use a centralized control.

This remotely controlled system,
located in Beijing,

can operate 64 curved gates
to control the flow rate.

It took engineers
5 years to complete

the 6-mile-long Shahe aqueduct.

Water can now cross
the flood-swept area.

But the next obstacle
on the central route

is much harder to overcome.

143 miles north of the aqueduct

is one of China's
biggest rivers.

This is the yellow river,

and it is the second-longest
river in China.

At over 3,000 miles long,

laden with more than
a billion tons of silt,

and with a highly erratic flow,

the yellow river
is too unreliable

to supply enough good water
to the north.

So the south-to-north diversion
project has to cross it.

The yellow river is
especially difficult to cross

because it wanders
its course every year

and it really changes a lot.

And the central route
is gravity-fed.

To keep the water
flowing downhill,

building above is not an option.

So engineers had to dig
underneath into a tunnel.

So digging a very long,
very deep tunnel

in this very soft ground
is a huge engineering challenge.

At the tunnel entrance,

the scale of the challenge
comes into view.

I think it's really amazing
that all this water

slowly goes under
this huge yellow river.

There's an 8-meter drop
that goes from the south side

to the north side.

This keeps the water
flowing under gravity.

To ensure the water
flows without pumps,

the tunnel's entrance
is higher than its exit.

The pressure caused by gravity

will push the water
under the river

and keep pushing it upwards...

An amazing 148 feet
to the other side.

But with pressure inside the
tunnel from the force of water

and pressure outside the tunnel
from the weight of the river,

engineers needed a solution
to prevent any failures.

Engineer Hu Jingyu is
at the project's crossing point.

The yellow river tunnel

uses a double lining structure.

Let me show you.

The outer lining
is designed to withstand

the outside water pressure,
and the inner lining

is to withstand
the inside water pressure.

Between the two linings,
there is a drainage blanket

which is about
6 millimeters thick.

At the bottom,
we set three drainage pipes.

These will collect
all the leaking water

and drain it away
as soon as possible.

This releases the pressure
between the two linings.

With the plan
for the water pressure in place,

construction of the tunnel
could begin.

When the water
started to flow to the north,

I was very excited
and I really wanted to cry.

Once it crosses the
yellow river,

the water can flow unobstructed
to Beijing.

The south-to-north water
diversion project

will carry trillions of gallons
of water to Beijing.

But the central route
has more than 621 miles

of open channels
that are difficult to construct.

To build a channel as long
as this is a huge challenge.

That's moving billions
of tons of earth.

Could a solution lie

with a pioneering
19th century railroad engineer?

So what we're going to do now
is test the accuracy

of the steam shovel
using this apple.

China's south-to-north
water diversion project

is the world's largest.

It connects the wet south
with the dry north.

And New York-based
architect Wendy Fok

is on an incredible journey

to see the scale of this
groundbreaking engineering.

A dam was raised 49 feet
to form a reservoir

for over 7 trillion gallons
of water.

From here, the water flows
through a 6-mile-long aqueduct

and a 2.5-mile-long tunnel
on its way to Beijing.

After moving water across
the mighty yellow river,

engineers are dealing
with another challenge.

How do you move water
across a country?

For most of the central route,
it's aboveground

in huge, open channels,
just like this one.

Along the central route,

there are more than 620 miles of
open channels

that had to be dug quickly.

But to build a channel
as long as this

is a huge challenge.

That's moving billions
of tons of earth,

and digging slopes like this
is not straightforward.

29 billion cubic feet of earth
and rock needed to be moved.

To find a solution,
the engineers need inspiration

from one of
history's innovators.

Crane operator Katie Kelleher
is moving soil near Birmingham

in England�s west Midlands.

The industrial revolution

in the mid-19th century
in Britain and America

meant we needed
a lot more transport links.

This led to planning
of new railways and new canals.

At the time, these projects
could only be dug by hand.

Digging by hand does get
the job done, as you can see.

The problem is,
it's really, really slow.

The engineers needed to come up
with a new way

to move earth really fast.

In 1835,
civil engineer William Otis

was working on a 41-mile-long
railroad in Massachusetts.

To help with
this backbreaking work,

the 22-year-old devised
a groundbreaking invention...

...the steam shovel.

This monster machine uses
around 1 ton of coal a day

to heat almost 3,000 gallons
of water to make steam.

The pressure from the steam
moves 6 pistons,

which drive cables to move
the boom and dipper up and down

or turn and propel the machine.

William Otis wanted it
to be based around

the guy working with the spades.

So you can see
you've got the beam here

and you've got the dipper
down here,

so it's a bit like an arm.

So it's a bit like my arm,
up to my elbow,

and my hand's coming down
into the bucket.

So if you think of it a bit
like a gentleman digging

and working away like that...

So this machine actually
replaces the work of 30 men.

With the help of owner Graham
and furnaceman David,

Katie's getting a unique chance

to operate
the steam shovel herself.

You have three levers...
One to slew it 'round,

you have one to move the bucket
up and down,

and you also have a button to
release the bucket.

Unless you know
what you're doing,

something like this
is very, very difficult.

Okay.

Take the weight on the brake.
Right, push it there.

Put on your brake.
Yep.

That's it.
Slew around.

The way this arm works is like
nothing I've ever seen.

Pull the right?

Yeah.

Whoa!

So you can see, the steam shovel
takes a lot of effort to drive.

It is not easy at all.

It doesn't have any electronics.

It's quite hard unless
you know what you're doing,

and I'd imagine things
can go wrong very easily.

So I think I'll let the expert,
Graham,

show us how it's done properly.

With Graham at the controls,

it's time to show
what this machine's capable of.

So what we're going to do now

is test the accuracy of this
steam shovel using this apple.

The goal
is to pick up just the apple

with as little soil as possible.

So, as you can see,
we did pick up

quite a bit of soil as well.

But for 100 years ago,
it was very, very impressive.

William Otis' steam
shovel was able to quickly

and accurately shift
more than 550 tons of earth.

In addition
to America�s railroads,

steam shovels dug some of
the world's longest canals,

including the
50-mile-long Panama canal.

And by the late 19th century,
there were hundreds

of these amazing machines
across America and Britain.

When we think of engineering
now, we think of excavators.

They're almost everywhere.

We owe all of these excavators
to the brilliant William Otis

and his magnificent steam
shovel machines.

In China, 5,000 excavators

are digging 29 billion cubic
feet of earth and rock

to create the channels
that make up

the south-to-north
water diversion project's

central route.

But the sides of the channel all
need to be dug at the same angle

to ensure that the concrete
facing on top won't crack.

So some of the excavators
are equipped

with cutting-edge technology

far beyond anything William Otis
could have imagined.

In China, 5,000 excavators are
being used to create channels

that will make up
the central route

of the south-to-north
water diversion project.

To ensure the concrete facing
on top of these channels

won't crack, they will need to
be dug at the same angle.

The excavators are equipped
with cutting-edge technology

to get the job done.

Site manager Jorg Schittenhelm
oversees the new breed...

The laser-guided excavator.

The apple test is used to see if
the laser-guided digger

can pick up the apple with more
precision than the steam shovel.

The excavators
are extremely accurate,

but in China, they must
repeat the same maneuvers

again and again.

This time, the apple test
is more challenging.

With the start position
measured and memorized,

the test can begin.

This laser-guided technology
is invaluable

for the 621-mile-long open
channels.

Engineer Wang Shouming oversees
the Jiaozuo open channels.

During the construction,

we used a lot of innovations
and newly designed machines,

which improved the efficiency
of our construction.

Because the excavator
has a track,

that means it can pass
through the muddy land

and the slope of our canal,
so it's very powerful.

Secondly, it is flexible.

It can move forwards
and backwards

and rotate 360 degrees quickly,

which also ensures
that it has a high efficiency.

Thirdly, it has
a powerful bucket

which can scoop up
1 to 2 cubic meters in one go.

Excavated with laser precision,

the 621-mile-long open channels
can be dug 30 percent faster.

But some sections need
extra treatment

before the water
can start to flow.

Engineer Cheng Dehu
has been looking at the problem.

The central route

of the south-to-north
water diversion project

will pass through

more than 380 kilometers
of expansive soil.

This clay-ridden section of soil
expands as it gets wet

and shrinks as it dries.

This movement could cause
the channel to crack.

The solution we
used was to add 5 percent cement

to the weak, expansive soil,

which completely changes
its features.

After stabilizing
the expansive soil,

engineers could apply the
finish to the open channel.

The operation in
the past five years

shows the treatment works well.

But as the central route
finally reaches Beijing,

engineers will have to design
a solution that allows the water

to travel under one of
the busiest cities in the world.

More than 850 miles away

from its starting point
at the Danjiangkou dam,

the central route

of China's south-to-north
water diversion project

is approaching Beijing.

Now the water will have
to travel

under one of the busiest cities
in the world.

Deputy chief engineer
Wang lei oversees the route.

The underground construction
is very complex.

There are railway bridges,
highway bridges, and rivers.

The distance between
the bridge paths and our tunnel

is as little
as 1 meter in places.

In the past three years,

the citizens of Beijing
weren't affected at all.

They didn't even notice that
there was such a massive project

being constructed
under the roads and subways

they use every day.

The water from the central route
has finally arrived

at the Tianjin reservoir
in Beijing.

After a 15-day journey,
the water transferred

by the south-to-north
water diversion project

is flowing to us
from this opening.

Flowing entirely by
gravity across China,

along the largest aqueduct
on the planet,

through the colossal
yellow river tunnel

and along 621-mile-long
open channels...

...the water's journey
is complete.

The water has made it
to Beijing.

It traveled from the south
to the north of China.

70 percent of Beijing's water

comes from the
water diversion project.

It's an engineering marvel.

It's one of the largest
water diversion projects

in the world.

It's amazing how
the engineers were able

to design open channels,
aqueducts and tunnels.

The south-north
water diversion project

is truly one of the most
amazing engineering projects

that I've ever seen.

The Danjiangkou
dam and reservoir

hold over
7 trillion gallons of water.

The water flows by gravity
for 870 miles

from the south
to the north of China.

The 6-mile-long Shahe aqueduct

will transport almost 100,000
gallons of water per second.

At the yellow river,

the water travels along
a 2.5-mile-long tunnel

before reaching Beijing.

This water diversion project
is the latest

in China's long history
of engineering achievements.

I feel this project
is magnificent.

I'm very proud
to be a part of it.

Seeing this
clear river flowing to Beijing,

it means the city
can enjoy fresh water.

I'm so pleased.

Wow!

By drawing on the
innovators of the past,

many challenges
have been overcome.

I think that this is

the most magnificent water
diversion project on earth.

It took us many years to build,

but it will benefit our
citizens for thousands of years.

I'm incredibly honored

to be part of the south-to-north
water diversion project.

The engineers

at the south-to-north
water diversion project

have succeeded in making
the impossible possible.

Repair and Synchronization by
Easy Subtitles Synchronizer 1.0.0.0