Ghosts of Machu Picchu Page #3

---

during the remainder

of his life this king devoted himself

to building magnificent temples

and palaces and strong castles.

The beautiful stonework at Machu Picchu-

so similar in style to Pachacuti's

temples in other Inca cities

suggests that the same

hand was behind the structures here.

But the most convincing evidence

linking Pachacuti to Machu Picchu

comes from a Spanish register,

held in the Colonial Archives in Cusco.

Dated 1568, it mentions

the town of Picchu

with a clear reference to its owner,

Inca Yupanqui, also known as Pachacuti.

The evidence is convincing.

It is Pachacuti, the first Inca emperor,

who ordered Machu Picchu's construction

and in a place that

would give any engineer pause.

If I was called in by Pachacuti

and ordered to build Machu Picchu at that

particular location, I would've gulped.

Engineering wise, it would seem

almost impossible to handle.

Fifteen years of study

by hydrologist Ken Wright

and a team of engineers is revealing

how the Inca pulled this off...

because the steepness

of the site isn't the only problem.

Machu Picchu also receives

torrential rains each year,

triggering frequent landslides.

And the site is crossed by not one,

but two earthquake fault lines,

making it a terrible place

on which to build a city of stone.

The location does have two virtues:

a nearby fresh water spring

and a supply of granite

there's a quarry right on the site.

When the Inca engineers

turned to building,

their first step would have been

to shore up the mountain.

They did it by constructing

a remarkable bulwark of terraces.

As Astete's team rappels

further down the cliff face,

they are discovering hundreds

of new terraces hidden below.

Usually, when people

refer to Machu Picchu,

they're only thinking about the Inca

buildings on top of the ridge.

But construction

has to begin at the bottom.

In other words,

you have to start with the terraces.

Terraces are fundamental to Machu Picchu.

While some terraces would have been

used for small-scale farming,

their primary purpose

was to hold the mountain in place

while draining a huge

volume of rainwater away.

That averages about 76 inches per year

and in terms of let's say Middle America,

that's a lot of water,

roughly two and halftimes as much as

the city of Chicago would get.

Left unmanaged,

that rainwater would turn the hillsides

to mud and Machu Picchu would slide away.

The Inca avoided that by creating

a sophisticated drainage system.

Inside the terraces, archaeologists

found a layer of rich topsoil.

Under that, a layer of sandy dirt,

and finally, gravel and larger stones.

We could say that they are

filtering galleries, meaning,

even when you get a lot of rain,

the terraces never flood

because the water is filtered

through these progressive

layers of material.

Instead of racing down the mountain,

the water slowly works its way into

the ground so there's almost no erosion.

With this basic design in hand,

the Inca fixed the first terrace into

the mountain, then started on the next,

replicating their way to the top.

Once there, Inca engineers had to reckon

with an even bigger water problem.

This is a city paved with stone

with few places for rainwater to go.

But the Inca had foreseen that problem,

and during construction carefully

placed more than a hundred drains

throughout the city.

Many of these drains delivered the runoff

from the elevated parts

of the city into the central plaza.

Further digging there revealed

a remarkable innovation

to handle all of that water.

Beneath the usual layers

of top-soil and gravelly dirt,

Wright's team hit a thick

layer of white granite chips

the spoil from years

of Inca stone cutting.

In effect, what the Inca did was

to build an underground drainage system,

a type of conduit,

to carry water safely away.

These were colossal earthworks,

extending nearly 2.7

meters below the surface

and encompassing several hectares.

They collected water

and shunted it away from the city.

The Inca engineers

spent about 50 percent,

maybe 60 percent over their overall

effort, underground, doing foundations,

site preparation, to make sure

that Machu Picchu would last forever.

So as vast as the city appears,

there's 60 percent more of it

underground, holding it all in place.

While the lnca went to great

lengths to get rid of water,

they also built fountains

which seem to celebrate it.

There are 16 fountains in the city,

each beautifully designed...

and a practical source of drinking water.

The fountains

are fed by a natural spring,

found nearby on the flanks

of Machu Picchu Mountain.

From there, the Inca engineered

a canal whose 3 percent grade

was carefully crafted to deliver just the

right amount of water to the fountains.

Wright calculated the flow to be

between 23 and 1 14 liters per minute

depending on the time of year

enough to sustain a population

of close to a thousand people.

It was remarkable, it was something

that created great respect by us,

for the Inca engineers

all those years ago.

It is a respect

also shared by Astete's team

as they restore

the Inca's original stonework.

In spite of their lack of iron tools,

the Inca were somehow able to transform

granite, a notoriously hard stone.

There's a clue to how they

did this in Machu Picchu's quarry.

We see here the basic method

the Inca used to cut rocks.

The idea is to create a "neck" in the

block and then cause it to fracture.

It was bone-jarring work.

The technique the Inca

used was direct hammering.

With the rough blocks, they'd

start with a large tool, like this one.

As you can see...it sheers very easily.

Then they'd gradually use the smaller

and harder tools to give it that strong,

smooth surface.

Once the cutters had roughed it out,

they put the stone on log rollers or mud

and pulled it close

to the construction site.

The final step was to move the stone

into place, and match it to its mate.

And here is the indentation they made,

which matches the edge

of the rock below it.

It's held up by this wedge until

they shape the two surfaces to match.

Then the wedge is removed and

the two stones fit together perfectly.

Here you can see...the brace points they

used to push the block up into place.

They put beams here to lift the rock up.

Once the rock was in place,

these points were beaten, just as you see

here, and here, in all these other rocks.

That means that the finishing

work was done at the site.

We can see that

this corner wasn't finished yet.

All this portion was yet to be cut off

in order to finish the wall.

Driven by a royal

mandate to build it here,

Machu Picchu is a tribute

to Inca engineering and artistry.

Its hundreds of terraces

buttress it from below.

The granite walls

are still solid after 500 years

because of a remarkable drainage system.

And it is crowned by

an ingenious lacework of fountains

Rate this script:0.0 / 0 votes