Why was it dammed?
How has it affected the lives of the local people?
Now using the atlas- complete your map following the instructions on the side
Much of the area the river runs through is desert
and area twice as big as the UK
 Early settlers dammed the river to provide water to
local cities and towns- much of this comes from the
snowmelt in the Rocky Mountains
 It also regulated the flow of the river to ensure a
constant supply of water to cities such as Las Vegas
and Phoenix
 25 million people in the SW rely on this supply

In Boulder
Canyon
Lake Mead and Lake Powell
are two largest man made
lakes in the USA

Using the sheet you have be given colour in
the bubbles to show the effects of the dam in
the following categories
 Social
 Economic
 Environmental
 Political



400,000 ha of land
is irrigated for
farming (most of it
in California’s
Imperial Valley)
Lake Mead and
Lake Powell are
major tourist
centres
Lake Powell offers
sailing, power
boating, water
skiing and fishing
and attracts over 2
million visitors a
year
The photo above was
taken on July 26th 2007, 7th
year of drought, lake level
dropped more than 100 ftlowest level since the late
1960’s.
Major tourist
destination- over
37 million visitors
a year
Water is
becoming
increasingly
scarce
Much of the water is lavish
and wasteful- lawns, parks,
golf courses and swimming
pools are seen as essential
and can only be maintained
by irrigation
90% of
water from
Lake
Mead
•Annual
rainfall of
50mm

‘Grass for Cash’- the city pays householders
$1 for every square foot of lawn they remove
 They hope they will replace them with Cacti and
other desert plants

Pumping water from aquifers (permeable
rocks underground) or oases- but what are
the issues with this?




This is north of Las Vegas
The oases in the desert
such as Ash Meadows are
rich in wildlife- 239 species
of bird, 27 mammals, 20
reptiles, 5 amphibians and
7 fish
25 of which are nowhere
else in the world
These are protected as
national wildlife refuges




The Las Vegas Water Authority wants to
pump around 2 million cubic metres of
groundwater each year from the aquifer
It will lower the water table
Springs will dry up
The unique environment will be destroyed

How will Las Vegas meet the demands of its
growing population and tourism industry?

How important is the natural environment
compared to urban lifestyles and jobs?