All language subtitles for NOVA S49E11 Saving Venice 1080p WEB h264-BAE (1)_track3_[eng]

♪ ♪

NARRATOR:
Venice, Italy, is in peril.

MAN
(speaking Italian):

NARRATOR:
The sea level rising.

♪ ♪

Extreme floods inundating
the city.

♪ ♪

ROSA SALZBERG:
It's really alarming

to see what happens to Venice
when it floods.

NARRATOR:
The city itself crumbling.

Salt is the enemy of Venice.

NARRATOR:
There may not be much time
left to act.

GEORG UMGIESSER:
There's a lot of responsibility
on us.

Because if you make it wrong,
people will feel it.

NARRATOR:
Scientists and engineers
are deploying

new solutions to defend against
the rising water.

From allying with nature...

GIOVANNI CECCONI:
This is the brick of life,
the mud.

DAVIDE SERNAGLIA
(speaking Italian):

NARRATOR:
...to a multibillion-dollar
flood defense system.

♪ ♪

A moonshot to save Venice
from the next inundation.

Can they succeed
and protect this ancient city?

♪ ♪

"Saving Venice."

Right now, on "NOVA."

♪ ♪

♪ ♪

NARRATOR:
Venice, Italy,

an ancient city of tradition,
arts, and culture.

♪ ♪

Home to iconic sights,

like the Rialto Bridge,

the Doge's Palace,

and the Basilica San Marco.

♪ ♪

But it is perhaps most famous
as the city of water,

where people and goods travel
by gondolas and boats

along a network of canals.

♪ ♪

These waterways connect the city

to a shallow, 210-square-mile
tidal lagoon,

separated from the Adriatic Sea

by a string of spits
and barrier islands

that shelter this natural
harbor.

Only at narrow inlets can ships
pass in and out of the lagoon.

Over the centuries,

the Venetians reinforced these
natural barriers

with sea walls and jetties.

But in the era of climate
change, these defenses

are no longer enough.

MAN
(speaking Italian):

NARRATOR:
Venice experiences sudden
floods,

known as acqua alta,

caused by the sea surging
through the inlets.

♪ ♪

These can inundate over 80%
of the city in a matter of hours

and leave the lowest-lying areas

under more than three feet
of seawater.

In the entire 20th century,

there were only nine of these
extreme floods.

In just the first two decades of
the 21st century,

there were 16.

Venice is facing the reality
of climate change.

MAN
(speaking Italian):

NARRATOR:
A stark warning of what may be
to come

for other coastal cities.

ED BLAKELY:
Over a hundred of our largest
cities are built on coastlines.

40% of the world's population is
on those coastlines.

So Venice is kind of the canary
in this coal mine.

As Venice floods,
undergoes these changes,

all the world's cities can see
what's going to happen to them.

♪ ♪

NARRATOR:
Now the eyes of the world
are watching

as Venice puts a new flood
barrier to the test.

SERNAGLIA
(speaking Italian):

NARRATOR:
A multibillion-dollar system

of gates designed to protect
the city

when the next flood threatens.

♪ ♪

SERNAGLIA:

NARRATOR:
But this barrier system is just
the latest

in a long line of Venetian
engineering solutions.

♪ ♪

Living on a lagoon has posed
problems

since the first settlers arrived
1,600 years ago.

(bells ringing)

The city of Venice wasn't the
original settlement.

♪ ♪

Six miles northeast of
the city,

the first homes were built
on the island of Torcello.

It is an area dominated
by a network

of shallow tidal creeks

and low-lying salt marsh
islands,

which offered food and shelter
to the first settlers.

♪ ♪

(speaking softly)

ALBERTO BARAUSSE:
Venice was born in the lagoon

because the lagoon was useful
to Venice.

So Venetians shaped the lagoon
the way they wanted.

NARRATOR:
But this environment posed
a problem.

How could they build on such
soft ground?

This is actually the, the
kind of landscape they,

they saw back then.

Uh, so very low-lying land,
marshes,

some islands,
but in general very wet,

swampy soil, such as this one.

I just want to show you how soft
this mud is

by trying and walk here.

I'm not that heavy weight.

I weigh 65 kilos.

But I'm sinking like this.

NARRATOR:
65 kilos is around 140 pounds.

If the mud can't support this,

how could it bear the weight
of a wooden house,

let alone one of Venice's grand
stone buildings?

♪ ♪

The solution?

Forcing wooden poles into
the soft mud.

These poles don't
support the weight.

(speaking Italian):

NARRATOR:
They transform the mud
around them.

The idea is to do a little
experiment.

When you plant many poles,

they compact the mud between
them.

The water is pushed out,

and the compaction of the mud
itself

make the mud more
capable of supporting weight.

NARRATOR:
Modern-day excavations
under the city reveal

that Venetians maximized the
compaction of the mud

by using a large number of poles
packed tightly together.

Directly on top,
they placed wooden planks,

then impermeable limestone.

And, above the waterline,
bricks.

BARAUSSE
(speaking Italian):

There you see, I'm lightweight,
more than him.

He can also try.

Okay, you see Omar is not
sinking,

because the effect of the poles

that compacts the mud
between them.

So it changes from more,
I would say,

fluid-like to more solid-like.

And the proof of this is when
we put the plank over there

and do the same thing on the mud
without the poles underneath,

you see?
There's a difference.

♪ ♪

NARRATOR:
This technology is the secret

of Venice's construction
and longevity.

It allowed the first settlers
to adapt the environment

and build the first houses.

The Venetians used wooden piles
to build on a cluster

of 118 marshy islands.

And over the centuries, they
created the city we see today.

BARAUSSE:
Venice is standing on mud,

it was built on mud,
and it will stand

for many, many years onwards.

NARRATOR:
But building on low-lying
islands

does have a drawback.

♪ ♪

Venice sits barely
above the level of the waves,

and this has always made
the city vulnerable.

SALZBERG:
Marin Sanudo was
a Venetian nobleman

who, for about the first three
decades of the 16th century,

kept an almost daily diary of

all kinds of things that were
happening in the city.

So it's a kind of gold mine
for Venetian historians.

NARRATOR:
On November 16, 1517,

he noted an event in the lowest
part of Venice,

the historic Piazza San Marco.

SALZBERG:
He writes that "on Monday
morning,

"as it had rained a lot,
both during the night

"and in the morning,
the water rose very much.

"So much so that
St. Mark's Square,

"from the Grand Canal to the
Rialto,

"and all the streets were full
of water.

"And it was neither possible to
travel

"nor by land nor with boats.

"And it was terrible to see the
water, which also

"continued to rise.

"So much so that nobody
remembers anything similar.

"It destroyed many goods in the
shops,

"and in many poor houses on the
ground floor,

it flooded all they had,
causing them great hardship."

It's an extraordinary
passage to read now,

because it's, it's very
evocative of what it's like,

it's like to be in the city when
there's an acqua alta,

when there's a high water.

NARRATOR:
For hundreds of years,

floods have swept through the
city.

And the cumulative effect of
these inundations

is placing the survival
of Venice's buildings in doubt.

ELISABETTA ZENDRI
(speaking Italian):

NARRATOR:
Scientists led
by Elisabetta Zendri

are monitoring the damage these
floods inflict on the city.

♪ ♪

Venice is known as the city
of canals.

And most of the historical
buildings

are in direct contact with
seawater.

♪ ♪

The building materials are
porous.

And seawater rises up the walls.

But this is not only water,
this is salty water.

And when the water evaporates
from the walls,

the salt, uh, can crystallize
into the pores.

♪ ♪

The crystallization pressure
causes

cracks of the pores.

And this is the final
consequence.

All the façade is compromised.

This problem is present in all
the buildings in the city.

Salt is the enemy of Venice.

NARRATOR:
As climate change raises sea
level, flooding is increasing.

More salt is getting into
the porous brickwork.

And the problem is only going
to get worse.

Models suggest the sea level
here could rise

more than 40 inches by the end
of the century.

It would seem the future of this
remarkable city is bleak.

But now there is hope.

♪ ♪

After nearly 20 years of
construction

and some $8 billion, a network
of enormous flood barriers,

called the MOSE, is in place.

It is designed
to block the floodwaters

before they reach the city.

In charge is Elisabetta Spitz.

♪ ♪

SPITZ (translated):
The MOSE is a masterpiece of
Italian engineering.

It has required so much labor,

so much research,
so much testing.

NARRATOR:
The scale of this project is
immense.

78 individual gates
are arranged in four barriers

that each stretch over
1,100 feet

across the inlets to the lagoon.

At Chioggia,

Malamocco,

and two barriers separated by an
artificial island at Lido,

the widest entrance.

(ship horn blows)

These inlets are the only way

for commercial ships to access
the lagoon.

♪ ♪

So the barriers are only lifted
when a flood endangers Venice.

Each gate is colossal,
approximately the size

of two tennis courts.

(translated):
These gates are fixed to
concrete beds

sitting on the bottom
of the sea.

NARRATOR:
During construction, each gate
was connected to these beds

by two immense hinges,
which allow them to pivot.

The gates are full of water,

which weighs them down
and keeps them

lying flat on the sea floor.

Until the team injects
compressed air

through a system of valves.

SPITZ (translated):
Air is pumped into the gates,

and they slowly rise.

And emerge from the sea.

Then they join together,

and hold back the high tide.

NARRATOR:
Most floods last fewer

than four hours.

So once the threat has passed,
the team can lower the barriers.

The MOSE is still

in its testing phase.

The team is perfecting
how to operate the barriers

when an acqua alta
threatens the city.

SPITZ (translated):
This project needs to work
perfectly.

Water cannot pass through.

(crowd cheering
and applauding)

NARRATOR:
But deploying the barriers

is far from straightforward.

An acqua alta arrives
incredibly quickly.

The water can rise as much as
12 inches

in just one hour.

And it takes over an hour
to raise all the gates.

♪ ♪

Venice needs
an early warning system

that predicts exactly
when the floods will arrive.

One factor is easy to forecast--
the tides.

The highest tides occur when
the sun

and the moon align,
and their gravitational pull

on the Earth's water combines.

Known as spring tides,

they happen twice a month,

and their timings can be
calculated years in advance.

But Venice doesn't flood
whenever there is a spring tide.

Another factor must combine with
the high water

to cause these inundations.

Understanding this is the key

to predicting an acqua alta.

It is an issue that
oceanographer Georg Umgiesser

has been studying for almost
40 years.

UMGIESSER:
Venice is a special city.

We have to protect it, because
otherwise,

generations will lose their
history.

NARRATOR:
To investigate,

he ventures far beyond
the city limits.

UMGIESSER:
It's a special environment.

It's just out of the world.

NARRATOR:
Georg's destination is a
scientific monitoring platform.

UMGIESSER:
I like to go out there.

It's very beautiful.

♪ ♪

NARRATOR:
Ten miles from Venice,

the monitoring platform sits
in a strategic position

at the northern end of the
Adriatic Sea,

a branch of the Mediterranean.

Here it detects any changes in
sea conditions

heading up this narrow body of
water before they reach Venice.

♪ ♪

Measurements from the platform,

along with data from across
the Mediterranean,

show that most of Venice's acqua
alta have something in common.

A specific type

of storm system in the
Mediterranean.

When you have a low-pressure
system, then you always have

a wind circulation which is
anti-clockwise.

The closer you get

to the low-pressure system,
the stronger the winds are.

And so once this is moving
now closer to, to Italy,

the winds also in the
Adriatic Sea

get stronger and stronger.

NARRATOR:
Known as the sirocco,

these winds are a major threat
to Venice.

♪ ♪

UMGIESSER:
Basically, they push the water

against the northern part,

and they push the water against
the lagoon.

Then you have, also,
the atmospheric pressure.

If you have lower pressure,

the water raises up.

♪ ♪

NARRATOR:
The twin effects
of low pressure and wind

can dramatically increase
the water level in Venice.

And if these coincide
with a spring tide,

an acqua alta can hit.

♪ ♪

This combination is known as
a surge tide.

As weather patterns change
around the planet,

the storm systems that drive

these inundations have become
more frequent.

♪ ♪

UMGIESSER:
Exceptional high tides
in Venice

are classified as water level
higher than 140 centimeters.

We saw in the last 150 years
18 events.

In the last three years,
we saw seven.

So something is changing,
clearly.

And the only reason why that
could be is climate change.

♪ ♪

NARRATOR:
But now Georg has
an early warning system.

♪ ♪

If a spring tide is due, and a
low-pressure system is forming,

Georg will see changes in
the water level at the platform

up to a week before the surge
tide arrives,

giving him a way

to alert Venice
that a flood is on the way.

UMGIESSER:
There's a lot of responsibility
on us.

It's a burden,
it's a burden, because if,

if you make it wrong, uh,
people will feel it.

NARRATOR:
Georg has detected

that water around the platform
is rising.

This is a forecast we issued
at the 30th of October.

Based on what we have here, we
can see that at a certain point,

just before the second of
November,

we should expect an event.

We are sure that something
will happen here.

♪ ♪

NARRATOR:
Georg is forecasting

that at 8:45 p.m.,

a flood will hit the city

that could cover
the lowest-lying areas

in almost 20 inches of seawater.

♪ ♪

At the MOSE,

Davide Sernaglia is in charge

of raising the barriers.

SERNAGLIA:
We have 70 guys

that work together here.

MARCELLO
(speaking Italian):

SERNAGLIA (speaking English):
And all have to work

like an orchestra.

♪ ♪

(speaking Italian):

(speaking English):
We have to check the compressor,
the valve,

the transmission system.

It's not possible to lost time.

But it's not simple.
(chuckles)

NARRATOR:
It's 7:45 a.m., and in the city,

workers are inserting
a backup plan

in case the MOSE fails to lift.

MAURIZIO SCARPA (translated):
We're positioning
the raised walkways

for the high-water event.

Tonight, this will all be
flooded.

If the MOSE isn't put up,
it will be flooded.

♪ ♪

They say it will be raised up,
but we can't say for certain.

♪ ♪

NARRATOR:
The approaching flood

is predicted to inundate nearly
half the city.

♪ ♪

Kiosk owner Walter Mutti

remembers the havoc when an
acqua alta hit

on November 12, 2019.

(water splashing)

MUTTI (translated):
At 9:30, suddenly
the wind changed.

(sirens blaring)

The flood sirens began to sound.

The wind suddenly became
merciless, extremely strong.

The tide was increasing out of
all proportion.

In 20 minutes, it had grown by

eight to 12 inches,
which is unheard of.

I was inside and I felt the
newsstand shaking.

I came out and the water
was already this high.

I went home, and when I came
back at 2:00 a.m.

to try and save the papers
and so on,

I couldn't see my kiosk anymore.

NARRATOR:
Walter had to wait three weeks

before he could solve the
mystery

of what had happened to his
kiosk.

MUTTI:
The fire department came
and they searched the canal.

They found a newsstand,
but it was full of mud.

I understood that
I lost everything.

♪ ♪

NARRATOR:
It cost $30,000
to restore his kiosk.

And Walter knows another flood
could spell financial ruin.

MUTTI:
I hope it never happens again.

I hope my fears
are not realized

and that the MOSE will work.

♪ ♪

NARRATOR:
It's 5:45 p.m.

Davide and his team
need to raise

all the gates before the surge
tide arrives in three hours.

♪ ♪

But there is bad news.

SERNAGLIA
(speaking Italian):

♪ ♪

NARRATOR:
The wind has changed direction,

pushing the storm
towards Venice

and causing the tide to rise
far faster than expected.

SERNAGLIA:

NARRATOR:
Davide orders the immediate
lifting of Treporti,

the northernmost set of gates.

SERNAGLIA:

MARCELLO
(speaking Italian):

SERNAGLIA:

MARCELLO:

SERNAGLIA:

♪ ♪

MARCELLO:

♪ ♪

NARRATOR:
But outside,
the storm intensifies.

(wind roaring)

MARCELLO:

SERNAGLIA:

♪ ♪

NARRATOR:
With all the Treporti gates
safely deployed,

Davide orders the lifting
of the other barriers.

SERNAGLIA:

♪ ♪

NARRATOR:
But two of the San Nicolò
gates aren't rising.

SERNAGLIA:

NARRATOR:
Each gate has safety valves

to prevent it from
accidentally rising up.

They have to be open
to allow air into the gate.

Otherwise, it won't lift.

SERNAGLIA:

MAN
(on radio, speaking Italian):

SERNAGLIA:

♪ ♪

NARRATOR:
Davide suspects that
the safety valves

haven't opened
on these two gates,

and they can't
rise into position.

And the storm
is driving the water

over three inches
higher than expected.

SERNAGLIA:

STEFANO
(speaking Italian):

♪ ♪

NARRATOR:
Davide decides the only option

is to risk rebooting the system.

SERNAGLIA:

♪ ♪

FRANCESCO
(speaking Italian):

SERNAGLIA:

(man speaks on radio)

♪ ♪

FRANCESCO:

MAN
(on radio, speaking Italian):

SERNAGLIA:

MAN
(on radio):

SERNAGLIA:

SERNAGLIA:

♪ ♪

NARRATOR:
The lowest parts
of Venice had been

forecast to be under
almost 20 inches

of damaging seawater.

But in the Piazza San Marco,

the only water is rain.

(people talking and laughing)

The MOSE has kept
the acqua alta

out of Venice.

SERNAGLIA
(speaking Italian):

♪ ♪

NARRATOR:
The following morning,

one Venetian in particular
is feeling positive.

(humming)

MUTTI (translated):
In the end, everything was fine.

Luckily, they lifted the MOSE.

And so personally, I,
like the rest of the city,

breathe a sigh of relief.

It gives you more faith,
definitely.

(chuckles):
However, tomorrow is
another battle.

(bell tolls)

NARRATOR:
Just 36 hours later,

Walter is proved right.

♪ ♪

The Piazza San Marco
is flooding.

♪ ♪

A surge tide is forcing seawater
up through the drains,

and a torrent is pouring
into the basilica.

♪ ♪

Inside, seawater is coming
up through the floor.

(water gurgling)

The reason is, three miles away,

the MOSE hasn't been deployed.

This isn't because
of mechanical failure.

For now, the barriers
are only raised for

the most extreme high waters.

♪ ♪

But smaller acqua alta
aren't blocked

and can still inundate the
lowest-lying parts of the city.

♪ ♪

There is a good explanation
for this decision.

Raising the flood barriers
too often also poses

a threat to the city
and its people.

♪ ♪

Giovanni Cecconi has studied
the lagoon for over 40 years.

Including almost 20
years working on the MOSE.

♪ ♪

CECCONI:
If we stop the tide,

if we use the MOSE
too much,

then the lagoon will die.

A healthy lagoon make

the Venice city healthier.

♪ ♪

NARRATOR:
And the key to
a healthy lagoon

is the tide.

CECCONI:
Twice a day,

we have a cycle
of inflow and outflow.

Because of the tide,
this water is mixed.

If you don't have
the stirring,

the same old water will get
more and more polluted.

NARRATOR:
And Venetians rely on
the lagoon's tides for one

of the most basic pieces
of the city's infrastructure.

CECCONI:
In Venice, you don't have
a septic sewage system.

So the waste is discharged
into the inner canal.

♪ ♪

NARRATOR:
When the MOSE is closed,
there is no tide,

and human waste accumulates.

♪ ♪

CECCONI:
It is very important that

the sewage system is flushed

by the tide.

♪ ♪

Because without the tide,

the, Venice will die
in its own, uh,

waste.
(chuckles)

NARRATOR:
Because of climate change,

Venice will need
to deploy the MOSE more

and more often.

But doing so will jeopardize

the city and its people.

♪ ♪

Scientists need to find

more ways to protect Venice

that work alongside the MOSE.

And the answer could be
hiding in plain sight:

the salt marshes.

This network of islands

acts as a natural
flood barrier,

channeling water and reducing
the power of waves.

And salt marshes
have another advantage.

They can keep pace
with sea level rise

because of the way
that they grow.

♪ ♪

These two plants are cooperating
to keep the soil higher.

The roots are very
important because

they hold the soil together.

At the same time,

they push the plant
a little higher.

This is the first
mechanism of counteracting

sea level rise,
producing more volume below.

♪ ♪

NARRATOR:
In summer,
these plants grow rapidly,

forming a thick carpet
of vegetation.

As high tides flow
over the salt marsh,

this web of branches and stems

acts like a giant fishing net,

trapping mud and debris
that then settle on top

of the salt marsh,
causing it to gain height

and providing a mechanism
for the marshes

to keep pace with
sea level rise.

CECCONI:
The more it is flooded,
the more it grows.

Each year, it is growing now

more than one or two
centimeter.

♪ ♪

NARRATOR:
These low-lying marshes
have yet another benefit.

They offer one of
the most potent ways

of fighting climate change
on the planet.

♪ ♪

Acre for acre, they can lock up
carbon 50 times faster

than the Amazon rain forest.

♪ ♪

But in Venice's lagoon,

salt marshes are in decline.

200 years ago, there were
nearly 70 square miles.

Now there are just 16.

♪ ♪

This decrease is linked
largely to one factor:

erosion from ships.

All cargo ships
access the lagoon

via the Malamocco Inlet.

They follow a narrow channel

to reach Porto Marghera.

♪ ♪

Just two miles from Venice,
this is one of the busiest

ports in Italy,

processing over 25 million tons

of cargo every year.

♪ ♪

Coastal researcher Luca Zaggia

is worried the city
and its lagoon

are at risk from all these
large cargo vessels.

♪ ♪

ZAGGIA:
The ships are getting bigger.

So starting from the '60s,
they doubled the size.

Today, we have ships
as long as 300 meters,

which is, uh, quite a lot
for this channel.

NARRATOR:
300 meters is the length

of six Olympic-size
swimming pools--

nearly 1,000 feet.

And when it comes to ships,
size matters.

♪ ♪

ZAGGIA:
This is a big wake.

Well, that was not bad.

So now, on the, on the side,

you see the water
bounces back and forth

for about 15, 20 minutes.

And the erosion
created by the ships,

it's undercutting the shore.

And we lost here
essentially 150 meters.

♪ ♪

NARRATOR:
The larger the ship and
the quicker it is moving,

the faster the erosion

due to the size of the waves.

ZAGGIA
(speaking Italian):

NARRATOR:
A ship's momentum generates

two different
destructive waves.

ZAGGIA:

NARRATOR:
First, a depression wave that
sucks water towards the vessel.

ZAGGIA:

NARRATOR:
And then a displacement wave
generated by the hull,

pushing water out of the way
as the vessel powers forward.

♪ ♪

The power of these two waves
combines to destroy the land

close to the channel.

The ship wakes, they arrive
until this point.

They undercut the cliff.

And finally,
slabs of soil will collapse.

Over a year,
you can lose about

four meters of shoreline.

♪ ♪

NARRATOR:
And on the other
side of the channel,

the waves from large ships

are scouring mud
from the sea floor.

Since the 1970s,

erosion has caused
the lagoon to become

over three feet deeper.

♪ ♪

And when the lagoon
gets deeper, it increases

the risk of Venice flooding.

ZAGGIA:
This is a buffer between
the land and the ocean.

You have no idea of how
many problems you can have

on the coast
without this buffer.

So we need
to limit the erosion

if we want to save Venice.

NARRATOR:
But that's becoming
more difficult.

Traffic in this
channel is increasing.

(ship horn blows)

Cruise ships used to sail
right through the center

of Venice.

Here, they traveled very slowly

and produced only
very small wakes.

(ship horn blaring)

But in 2019,

a cruise ship plowed into
a dock in the city.

♪ ♪

(people shouting)

(hull scraping)

NARRATOR:
Luckily, there were
only minor injuries.

But now the authorities
only allow cruise ships

in the Malamocco Canal,
where they are free to travel

at much higher speeds.

Luca believes this will
increase the erosion.

♪ ♪

ZAGGIA:
My opinion is, the lagoon,

it's not suitable
for large vessels.

We must be correct with
the environment, because, uh,

we inherited it from the past.

And we are in charge of it.

And this is what
protects Venice from,

from further damages.

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NARRATOR:
Protecting the natural
flood defense systems

in the lagoon is key
to the survival of Venice.

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And around the globe,
the idea of using nature

to counteract rising
sea levels is gaining traction.

Ed Blakely directed
the recovery effort

in New Orleans after
Hurricane Katrina.

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We've been removing salt marshes

and these kinds of things
that act as filters

for the water that
will come into a city.

♪ ♪

The floods that came in Katrina,

the surge that was coming up
the Gulf, the Mississippi,

the lack of the trees meant
it reached the city.

Had those trees
still been there,

New Orleans would
have been saved.

♪ ♪

In my view, natural solutions

are the best way
to protect populations.

Basically putting nature
back where it should be.

Mangroves are particularly
effective in dealing

with surges, because
as the river rises,

they absorb that,

and they dampen
the sea rise effect.

You can also start replanting.

Restoring the cypress trees
and things that were

in the canal systems that
contain the water and hold it.

And building barrier islands
that once were there.

Replacing them
makes a lot of sense.

I think nature is our only
ally in the future.

If we don't restore nature,
we have little hope

of restoring
and keeping our cities.

♪ ♪

NARRATOR:
But could Venice take the idea

of working with nature
one step further?

♪ ♪

Could the key
to saving Venice

be the geology
beneath the city?

♪ ♪

It's an idea that engineer
Pietro Teatini is exploring.

♪ ♪

TEATINI:
The idea is, by injecting

seawater into deep aquifers

or deep reservoir
below the lagoon bottom,

to try to uplift
the city of Venice

around 25 centimeter.

This is something that can
really be, be done,

and in practice, it works.

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NARRATOR:
Beneath Venice's lagoon,

there are layers with different
geological properties.

Some are impermeable clay.

These surround aquifers,

strata of highly absorbent
sandy deposits.

Injecting seawater directly
into these aquifers

would cause them to swell

and push up on
the layers above,

lifting the whole of Venice.

It's an ambitious plan.

But lifting land
by injecting water

is a proven technology.

♪ ♪

In the 1930s,
oil was pumped

from the Wilmington
Oil Field in California

in such vast quantities

that the land began to sink.

♪ ♪

By the late 1950s,

it affected an area
of 20 square miles.

And in some places,

the ground had dropped 29 feet.

Engineers began injecting

seawater under the ground,

which lifted the land up

and back to its previous level.

♪ ♪

Pietro and his team
have calculated

they could lift Venice
for $100 million,

a fraction of the cost
of the MOSE.

TEATINI:
The idea that we have is to
put ten wells around Venice,

centered on the
Bridge of Rialto.

We inject different amount

of water into each well.

And we adjust the pumping rate

in order to have
as uniform as possible

uplifting of the city,

but without generating
any kind of cracks or fracture.

We reach this maximum uplift

of about 20, 25 centimeter

in ten years.

NARRATOR:
Raising Venice nearly
ten inches would decrease

the impact of future surge tides

and sea level rise
in the city.

Working alongside the MOSE
and the lagoon's salt marshes,

it could reduce the risk
of Venice flooding

and help protect

the city's
centuries-old buildings.

♪ ♪

Venice was born out of its
natural

environment and clever
engineering.

Adapting the lagoon's
muddy islands

offered Venetians a way
to build their first homes.

Now, 1,600 years later,

they have come full circle.

Faced with losing their city to
climate change,

once again, they are innovating

with large-scale engineering

and the restoration
of their ancient lagoon.

Only by using multiple
approaches can they hope

to save Venice.

BLAKELY:
My view of the future of Venice

is that if it keeps going
the way it's going,

there will be no Venice
in less than 50 years.

But if it changes its course,

it can last another
thousand years.

That's up to Venice.

♪ ♪

♪ ♪

ANNOUNCER:
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on Amazon Prime Video.

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