This is the Mullaperiyar Dam.
It's been around since
well before your grandparents were born.
And it could fail at any moment now.
The Mullaperiyar Dam
is located in India's Kerala state.
For over 100 years,
the dam has provided
vital power and irrigation to Kerala
and neighboring Tamil Nadu.
But the days could be numbered
for this 54 m (177 ft) high dam.
Its design and technology
are not as advanced
as current standards require.
To make matters worse,
the region is prone to earthquakes.
A lot of them.
In 1979 and 2011,
earthquakes left structural
cracks in the dam.
Could the next quake crack
the dam wide open,
threatening the lives
of millions of people?
The day would start quietly
and peacefully.
You'd be standing
on the Mullaperiyar Dam
admiring its effectiveness
after so many years of service.
On one side,
there's a controlled,
powerful rush of water.
On the other side is a massive reservoir.
This dam has a volume
of 443 million cubic m (579 million cubic yd).
And in the monsoon season,
it would be full to the brim.
Water would barely top
over the dam's wall.
But your morning visit
would get shaken up
as the ground
suddenly trembles below you.
That was a minor earthquake.
It would last only a few seconds
and then life would return to normal.
Or so you'd think.
You'd hear a loud
cracking noise and run
to check the dam's edge.
The earthquake expanded a small crack
in the dam's bank.
And now,
water would start flowing through it.
A little at first,
then more and more.
Khairallah. We've got a problem.
You'd realize pretty quickly
that the hole reached
all the way to the reservoir.
Luckily, your survival instincts
would kick in,
and you'd run to the side
and get off the dam.
You'd just make it to safety
before the hole gives
way to a catastrophic breach.
Now the real trouble would begin.
A huge mass of dirty water
would burst through the structure.
It would take nearly
everything in its path along with it.
People nearby would face
the danger of an uncontrolled,
rushing river of soil and rock debris
with enough water to fill
180,000 Olympic-sized swimming pools.
You'd count your lucky stars
that you narrowly escaped death.
But now from your vantage point
at the dam's side,
you'd watch all the destruction happening.
You'd see people trying to run away,
only to be twisted up
and mangled in the flowing water.
Anyone sheltering inside a building
wouldn't be safe either.
The flood would rip whole buildings
off their foundations.
In the distance,
roads and bridges would get
washed away too.
The lives and livelihoods
of about 100,000 people
would be devastated
before they could get to safety.
But the dangers would not be over yet.
After about 45 minutes,
the flood would reach the
Idukki dam,
about 25 km (15 mi) downstream.
Theoretically, this dam should be able
to withstand the Mullaperiyar's floodwater.
But its full reservoir
could doom the Idukki dam.
And if all that pressure causes
the Idukki dam to breach.
All 15 interconnected dams
leading to the Arabian Sea
could fail too.
That would directly impact the lives
of over 3.5 million people,
leading to a grim future for you
and the rest of the survivors.
Everywhere you go,
you'd be trudging
through debris-filled mud.
And the water all around you
would likely make you sick.
That's because the flooding
would contaminate the water
with a huge variety
of metals, chemicals and wastes.
You and all the other survivors
would probably need to
relocate to other places.
Beyond the human
cost of this tragedy,
the dam would need to be redesigned
and rebuilt.
The cost would be in the billions.
The sad reality is that
this scenario is not a matter of if.
It's a matter of when.
The regional governments
that rely on the dam
have been fighting each other in court
about the dam's fate.
And a recent report from
the U.N. University's Water,
Environment and Health Institute
recommends the dam
be decommissioned.
If this scenario happened,
the whole world would witness
another tragedy
that could have been avoided.
Maybe melting all the world's ice
is another grim scenario we could avoid.
But that's a story for another WHAT IF.