The legendary 'Lost City
of Machu Picchu‘, located
high in the Peruvian
Andes, is without a doubt
the most important tourist
attraction in Peru and one
of the world's most
and civil engineering
The natural setting on the
eastern slope of the
Andes encompasses the
upper Amazon basin with
its rich diversity of
The whole archaeological
approximately 5 square
km. It is situated in the
Its climate is semitropical, warm and humid.
The Ancient City was built by the Incas on the summit of
"Machu Picchu" (Old Peak).
It overlooks the deep canyon of the Urubamba River in a
semi-tropical area 120 km (75 miles) from the city of Cusco
at 7,000 feet above sea level.
Machu Picchu was
probably the most amazing
urban creation of the Incan
Empire, with its giant walls,
terraces and ramps, which
appear as though they
have been cut naturally into
the rock escarpments.
This site was so well
constructed that even after
5 centuries of neglect in the
Peruvian jungle, only the
thatch and reed roofs are
The valley below and the
zig-zag road leading up
to Machu Picchu.
Machu Picchu was a complex of temples, palaces and
observatories and was believed to be the home of the Inca
From here, high priests made observations and calculations
enabling them to chart the heavens - a knowledge which gave
them both religious authority and temporal power.
Machu Picchu is also one of the Inca's best kept secrets,
since they did not leave written records and Spanish
chronicles make no mention of the citadel, it remains a
The City was discovered in 1911 by the American Yale
professor, Hiram Bingham.
The building style is "late imperial Inca" thought to have
been a sanctuary or temple inhabited by high priests and
the "Virgins of the Sun" (chosen women).
Excavations revealed that of the 135 skeletons found,109
were women. No signs of post Conquest occupation were
The original entrance to
the complex is on the
southwestern side of the
citadel at the end of the
Inca Trail, a short walk
away from "Intipunko "
(Sun Gate), the ancient
final check point to
The present entrance on
the southeastern side
leads to the agricultural
The complex can be
divided in three distinct
Urban, and Religious.
The urban section
starts at the wall that
separates it from the
agricultural area, this
group of buildings
were constructed on
the ridge that
descends abruptly to
the Urubamba valley.
3 Distinct Sections
View of left side from above. Urban on left, agricultural
on far right. Religious upper left.
The central plaza that separates the religious from the urban
section, has a great rock in the center.
The religious section contains splendid architecture and
One of the most important and enigmatic is probably the
Intihuatana shrine, this block of granite was presumably used
to make astronomical observations.
Curved outer temple of the Sun wall.
The "Temple of the Sun", is a circular tower with some of
the best stonework of Machu Picchu.
Its base forms a cavern known as the Royal Tomb.
Recent studies show that the actual purpose was for
The agricultural area consists of a series of terraces and
channels that serve dual purpose, as cultivation platforms
and as retention walls to avoid erosion.
Residential / Agricultural
Some smaller buildings next to large terraces are part of this
section and thought to have served as lookout posts.
In the southern part of
this section are found a
series of niches carved
on rock known as "the
jail" with elements that
include man size niches,
stone rings would have
served to hold the
prisoner's arms, and
The group of refined structures next to "the jail" is known
as the "intellectuals' quarters", with tall walls, nooks, and
windows built with reddish stone.
They are considered to have been accommodations for the
Amautas (high ranked teachers).
One of the buildings has
several circular holes carved
on the rock floor named the
"mortar room" believed to
have been used for
preparation of dyes.
The largest urban section in Machu Picchu is
located on the north western part. It is reached by
a 67 steps staircase and involves a group of
buildings not as finely constructed as other parts
of the complex.
Huayna Picchu, young peak, is as much a part of the site
as the buildings of the citadel, the towering granite peak
overlooks Machu Picchu to the North with a steep well
preserved original Inca path, well worth the one hour climb
for an astounding view of the citadel and the entire valley.
Discovery: MACHU PICCHU
Hiram Bingham found
many objects of stone,
bronze, ceramic and
obsidian, but no gold or
There should have been
fabulous riches of these
metals comparable to
those found at the
'Temple of the Sun' in
Cuzco where even the
garden contained life-size
gold replicas of maize
and other plants.
The Peruvian scholar Dr
Victor Angles Vargas thinks
the city became
depopulated toward the
end of the 15th century
before the Spaniards
Perhaps the city was
ravaged by a plague so
terrible it was permanently
quarantined by the
What brought this about is
one of the deepest
enigmas surrounding this
Only from the nearby hilltop observatory of
Intipunku, can you visualize the full extent of this
great engineering and architectural site.
Machu Picchu sits on
the top of a mountain ridge
so where did the Inca get
In 1976, Ken Wright-the president of Wright
Water Engineers, of Denver decided to find out.
After all, who better to study the Inca water
supply than a water engineer?
Wright spent the next 20 years seeking
permission from the Peruvian government to
study water engineering at Machu Picchu.
In 1994 he was finally granted permission by the
Peruvian government, with political coaxing from
Wright soon discovered that the Incas had
accumulated a practical knowledge of hydrology,
hydraulics, drainage, and foundation engineering.
"They had a perfect site," notes Wright, but its
suitability would have been apparent only to a
The slopes were steep; how would buildings be
prevented from sliding downhill in a heavy rain?
How would drinking water be made accessible?
And from what source would the water come?
Left side of ruins.
The Citadel is a
urban planning, civil
Wright discovered that the Inca must have planned the city
carefully before building it.
First, the Inca engineers had to determine the exact
location of the spring and whether it would meet the needs
of the anticipated population.
Urban Planning. Water Source 1
The Wright team
found that the spring,
on a steep mountain
slope to the north of
Machu Picchu, is fed
by a 16.3 ha tributary
After conducting an inflow-outflow evaluation, the
team also concluded that the spring draws on
drainage from a much larger hydrogeologic
There was no ‘urban sprawl’ in this mountain
retreat of about 1,000 residents; thoughtful
consideration was made before the first stone
The placement of the residence of the Inka (the
title of the ruler is used today to name the
people) was determined by the location of the
The Inca engineers built the canal at a slope
that allowed gravity to pull the water at just the
speed they desired for the city’s use, then they
used that information to place the royal
residence, as well as, the city.
Natural Springs to Canal
A natural spring flows from a geological fault
above the city on the steep side of Monte Machu
The Inka’s gathered drinkable water from the
spring by building a wall in a cut in the
mountainside that they had made.
This stone wall was made to let water through,
unlike their watertight stone canal into which the
Enhancing the Water Source
The Inca enhanced the yield of the spring by building a
spring collection system set into the hillside.
The system consists of a stone wall about 14.6 m long and
up to 1.4 m high.
Water from the spring seeps through the wall into a
rectangular stone trench about 0.8 m wide.
Water from a secondary spring enters the canal about 80
m west of the primary spring.
The Inca also built a 1.5 to 2 m wide terrace to allow easy
access for operating and maintaining the spring works.
The spring system still works today, after some minor
repairs and cleaning were done.
Special consideration was
given to the water system:
a stone canal brought water
to the city from a mountain
fountains were built
throughout the city for
drainage and irrigation
systems were on integral
parts of the city.
Conveying the Water: The Canal
Before the city could be built, the Inca engineers
had to plan how to convey the water from the
spring-at an elevation of 2,458 m-to the
proposed site on the ridge below.
They decided to build a canal 749 m long with a
slope of about 3 percent.
Within the city walls, the water would be made
accessible through a series of 16 fountains, the
first of which would be reserved for the emperor.
Thus the canal design determined the location
of the emperor's residence and the layout of the
entire city of Machu Picchu.
The Inca built the water supply
canal on a relatively steady grade,
depending on gravity flow to carry
the water from the spring to the city
They used cut stones to construct a
channel that typically ranged from
10 to 16 cm deep and 10 to 12 cm
wide at the bottom.
Wright's team concluded that the
nominal design capacity of the
channel was about 300 L/min.
The canal lost little water due to its tight fitting
stones and additional clay sealant.
The canal was so well built that today, after 500
years; it would work after minor repairs (mostly
clearing old landslides that have filled the canal
During the cities occupation the canal was
maintained by an Inka access road.
The 749 meter (2,457 foot) canal ended at the
first of 16 fountains built in the city.
Canal to the Fountains
The canal descends the mountain slope, enters
the city walls, passes through the agricultural
sector, then crosses an inner wall into the urban
sector, where it feeds a series of 16 fountains
known as the stairway of fountains.
The fountains are publicly accessible and partially
enclosed by walls that are typically about 1.2 m
high, except for the lowest fountain, which is a
private fountain for the Temple of the Condor and
has higher walls.
At the head of each fountain,
a cut stone conduit carries
the water to a rectangular
spout, which is shaped to
create a jet of water suitable
for filling an aryballo -a
typical Inca clay water jug.
The water collects in a cut
stone basin in the floor of the
fountain, then enters a
circular drain that delivers it
to the approach channel for
the next fountain.
The order of the fountains shows the social
hierarchy of the city.
The first fountain is, of course, in front of the
residence of the Inka.
The second and third fountains are by temples
(used by the religious class).
The third fountain (by the Temple of the Sun-“El
Torreon”) can be bypassed with a sort of ‘stone
faucet’ by passing the water though an
underground stone conduit (‘stone plumbing’).
Fountains 4 to 15 are for public use and the final
fountain is by the Temple of the Condor.
The fountains were designed for convenience:
the water flowed over a stone ‘lip’, making the
filling of water jugs easy.
Their drainage system shows the Inka people
appreciated water sanitation.
The fountains’ basins drained through stone
conduits past the remaining fountains.
This prevented dirty water from flowing into
fountains ‘down stream’.
Fountains to drainage
The Inca understood the importance of pure
The surface drainage system generally directed
agricultural and urban storm water runoff away from
the water supply canal.
The Inca apparently did not use the fountains for
The emperor, for example, had a bathing room with
a separate drain, so that bathing water did not
reenter the water supply.
View of terraces and rain
channels from thatched hut.
Perhaps the most visually striking features of the drainage
system are the agricultural terraces.
Machu Picchu includes 4.9 ha of agricultural terraces, which
are held in place by stone retaining walls.
In addition to maximizing the land available for farming, the
terraces also protected the agricultural sector from erosion.
sits atop the
Wright conducted soil analyses that showed that the Inca
constructed the terraces with subsurface drainage in mind.
The Inca layered each terrace for efficient drainage, with a
layer of stones at the bottom, followed by gravel, sandy
material, and topsoil.
The terrace structures also
promote good surface
The slope of the terraces
generally directs water
toward a system of drainage
channels that are integrated
with stairways and other
These channels direct the
drainage water to a large,
east-west main drain that
runs through the center of
Machu Picchu, separating the
agricultural and urban
Gravity flow carries runoff
into the main drain from both
sectors, taking it safely away
from the city.
In the 15th century, the buildings in the urban sector
would have been covered with thick thatched roofs.
Because of the density of buildings with
impermeable roofs, Wright estimated that about
60% of the water yield from the urban area would
have occurred as surface flow.
The Inca constructed their plazas in the same way as the
terraces, with a deep subsurface layer of rock chips.
The plazas received runoff from other areas of Machu Picchu,
and the subsurface layer of rocks helped the water to
penetrate the ground quickly.
Drainage in the Urban Sector
To deal with the runoff problem, the Inca
incorporated about 130 drainage holes into the
walls and other structures at Machu Picchu.
They also integrated numerous drainage channels
into stairways, walkways, and building interiors to
carry runoff to the main drain.
One especially carefully constructed channel
drains water away from the entrance to the
To direct water away from building foundations, the
Inca carved channels that would collect the water
that dripped from the roofs.
Machu Picchu's well-designed drainage infrastructure is
one of its most remarkable secrets. It is also one of the
keys to its longevity, says Wright: "They built for
permanency. They didn't do anything halfway."
At Machu Picchu, drainage was a serious problem. The
site rested on top of a ridge with a roughly 50 percent
slope and received almost 2,000 mm of rainfall.
For their city to endure, the Inca had to find a way to
keep it from sliding down the mountain.
Flooding is controlled by two methods:
1st a level area of the canal is designed to overflow into a
terrace field for irrigation;
2nd was an overflow outlet by fountain 4 and the main
stairway (like slue-ways on modern civil engineering projects).
sewage system was
built right into the
walls of each new
This intricate system has as least 127 drainage
outlets and is a good representative of Inka
The Inka’s enjoyed a system superior to their
European contemporaries who suffered from
diseases caused by open sewers in the streets.
Back-up Water Supply
Wright's team discovered another, previously
unknown series of fountains on the eastern side
of the ridge, downhill from Machu Picchu.
These fountains received their water not from the
canal but from intercepted groundwater drainage.
The Inca had to identify the dry-weather
groundwater flow locations to concentrate the flow
for use in the fountains.
Adjacent to some of the fountains, an important
trail connected Machu Picchu to the Urubamba
River in the valley below.
After clearing away the dense forest undergrowth,
Wrights’ team restored the water flow to this
second series of fountains for probably the first
time in 450 years.
Life in the Incan empire was
measured by a thousand
year cosmic cycle called an
Inti, which means 'Sun'.
This thousand year cycle
was then divided into
halves, each of which was
referred to as a Pachakuti.
During the 500 years of the
Pachacuteq, the greatest
spiritual leader of the Incas
and the builder of Machu
This was a time of light
when the Inca Empire
flourished and there was
expansion and good fortune.