ACTIVITY 19: GLOBAL WATER RESOURCES
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Activity 19: Global Water Resources
Half Full or Half Empty?
Essential for life, water is the most important natural resource in the world
today. As with all resources, however, it is distributed unevenly. Some
countries have an abundance of fresh water, while others—the majority—have
limited access to this vital commodity. The following activity will explore some
basic facts about the global water situation, and will then look at the effect of
water on agriculture in three very different locations. You’ll also examine the
relationship between water and the disturbing trend toward desertification,
especially in Africa. The final part of the activity challenges you to decide
whether or not countries with apparently abundant water reserves, such as
Canada, should be sharing their water wealth with countries in dire need.
Part 1: Basic Water Facts
Before you go any further, it’s important that you gain a better understanding
of water and its importance to the Earth. The first question is “Where are all of
the Earth’s water resources located?” Take a look at the table titled
“Distribution of the Earth’s Water” on page 129 of the Atlas and answer the
following questions.
1.
Where is most of the water on Earth located?
2.
Which source of water listed is least abundant?
3.
Identify which resources are suitable and accessible sources of fresh water
for human consumption.
4.
In general, how does the volume of available freshwater resources compare
with the volume of salt water and inaccessible water resources?
5.
Use the Freshwater resources map on page 141 of the Atlas to complete
the chart on the next page. If a region includes a variety of resource levels,
use compass directions to describe the differences. The first one is done
for you.
6.
Why is a country like Madagascar in southern Africa unable to provide all
of its population with access to fresh water despite having abundant
resources? Use the Physical map of Africa on pages 108–109 of the Atlas
and the Distribution of the Earth’s water table on Atlas page 129 to help
with your answer.
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ACTIVITY 19: GLOBAL WATER RESOURCES
Region
Description of Freshwater Resources
North America
Generally abundant, but the amount
decreases as you move south and closer
to the Equator.
Percentage of Population with Access to
a Water Source (estimate)
All citizens in Canada and the United
States have access to a water source,
while 86% of those in Mexico do.
South America
Europe
Asia
Africa
Oceania
Copyright © Oxford University Press Canada 2009.
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ACTIVITY 19: GLOBAL WATER RESOURCES
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Water and Agriculture
What does all this water get used for? Many of us only think of personal uses of
water such as brushing our teeth, watering the garden, bathing, or drinking.
But domestic use accounts for only a small percentage of total water
consumption. Some is used by industry, especially for power generation, but by
far the largest volume of the world’s water resources is used in agriculture. In
the last 100 or so years, agricultural use has increased more than sevenfold. In
places like Africa and Asia, an amazing 85–90 per cent of freshwater use is for
agriculture.
7.
Why do you think the use of fresh water for agricultural purposes has
grown so much over the past century?
Irrigation can be defined as the process of supplying crops with fresh
water through channels, streams, pipes, or other human-induced
solutions. The amount of irrigated land around the world for agricultural
purposes is rising. In many countries, this creates a strain on freshwater
supplies. Let’s compare the water resources and levels of irrigation on two
continents: Africa and Asia. Use the maps on Atlas pages 129 (Water
surplus or deficiency) and 141 (Irrigated land) to answer the following
questions.
8.
Describe the pattern of water resources you observe across these
continents.
9.
We can observe that Asia generally uses more of its water resources for
irrigation purposes. What reasons can you hypothesize to explain why
Africa does not irrigate more of its land to increase its agricultural output?
10. Predict what future impacts the continued use of fresh water for irrigation
in Asia may have.
Copyright © Oxford University Press Canada 2009.
ACTIVITY 19: GLOBAL WATER RESOURCES
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Part 2: Comparing Three Cities
We have learned from Part 1 that many parts of the world have a severe
deficiency in water resources. You have also seen that the most significant use
of global water resources is for agriculture. The following exercise will examine
current water availability and the resulting agricultural practises. Let’s take a
closer look at the situation at three climate stations in different parts of the
world: La Paz, Bolivia; Montréal, Canada; and Tamanrasset, Algeria.
11. Complete the chart on the next page using maps and information found on
Atlas pages 126, 129, 132–133 and 140–141 as well as in the Gazetteer.
12. Look at the annual precipitation figures for the La Paz area. How do you
reconcile the amount of rainfall with the fact that this location has a water
deficiency? Why does it have so little arable land?
13. Why does the Montréal area have such a low percentage of irrigated land?
14. In which of these three locations is lack of precipitation most likely to be a
major problem?
15. How do the Montréal area’s precipitation patterns give it an advantage over
the other two locations for agriculture?
16. Which location in your opinion has the least potential for agriculture?
Why?
Copyright © Oxford University Press Canada 2009.
ACTIVITY 19: GLOBAL WATER RESOURCES
La Paz, Bolivia
Montréal, Canada
Latitude
Metres above sea level
Annual precipitation
Climate region
Natural vegetation
region
Types of agriculture
Arable land (hectares
per capita)
Irrigated land
Water surplus or
deficiency
Copyright © Oxford University Press Canada 2009.
Tamanrasset, Algeria
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ACTIVITY 19: GLOBAL WATER RESOURCES
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Part 3: Desertification and Groundwater
We’ve looked at who has water and who doesn’t, and considered some of the
ways that water can affect agriculture in a region. Now let’s look at what severe
water shortages can do to an area that is already under stress.
An unwelcome environmental trend that is occurring around the globe is
desertification. Desertification is the process by which arable land is being
degraded (made unsuitable for agriculture) and changed into desert as a result
of poor land use, population pressures, or climate change.
Compare the map on the bottom of Atlas page 130 with the map of
Freshwater resources on Atlas page 141. Many of the areas at risk of
desertification are areas close to desert areas that receive little precipitation. If
left alone, these areas would probably not be at risk of becoming desert. But
with human interference, the land becomes severely distressed because it
cannot sustain the practices we put to it. A dry but natural savannah can
support natural plant species and wildlife. It cannot support herds of cattle or
other forms of agriculture without deteriorating into useless desert. Irrigation is
one way to address this problem, but irrigation requires adequate freshwater
resources and the infrastructure as well as the means to pay for transporting
the water.
Let’s take a closer look at the situation facing Northern Africa.
17. a)
Using the data on pages 105–107 and 140–141 of the Atlas, write a
brief report explaining how the water situation in the Sahel region of
Africa may affect the process of desertification. Make sure to include
the following topics:
•
rainfall patterns from 1950 to 2005 in the Sahel
•
average annual precipitation
•
temperature ranges
•
freshwater resources
•
irrigated land
•
natural vegetation
•
types of agriculture
•
b)
employment in agriculture
In your report, predict how the loss of arable land is likely to affect its
economy.
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ACTIVITY 19: GLOBAL WATER RESOURCES
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The Sahel region of Northern Africa is certainly facing a water crisis. But is
continuing desertification of these lands inevitable? Not necessarily. Parts of
this dry and arid region contain groundwater resources that could be used to
supply more of the water needs of the people who live there.
Groundwater can be defined as the fresh water that seeps into the ground
through the natural processes of the hydrologic cycle and is stored in aquifers
beneath the Earth’s surface. In humid regions, these freshwater reserves are
sometimes just below the surface, while in arid regions the water table may be
hundreds of metres underground. The Sahara Desert region in Northern Africa
has a huge underground supply of water in a natural groundwater reservoir.
One of the world’s most ambitious engineering projects to date, the Great ManMade River Project, is currently harvesting these water resources and
transporting the water to cities along the coast of the Mediterranean in
countries such as Libya in Northern Africa.
18. Using the Internet, gather information regarding the Great Man-Made
River Project and answer the following questions.
•
What is the location of the reservoir?
•
What is the geological background of the area?
•
Who are the main beneficiaries of the project?
•
Why is the water being transported out of the desert to coastal
regions, instead of being used in the Sahara?
•
What is the long-term sustainability of this source of water?
Copyright © Oxford University Press Canada 2009.
ACTIVITY 19: GLOBAL WATER RESOURCES
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Part 4: At Issue—Water as a Commodity
Throughout this activity, we have been focusing on regions of the world that
face water deficiencies. But some countries have a surplus of freshwater
resources. While Canada contains a surplus of fresh water, not all of it is easily
accessible.
According to Environment Canada, Canadians are the world’s biggest water
wasters. We use an average of 330 L per day for personal domestic use, while
most people in water-scarce regions use less than 10 L per day. Yet the amount
of water we have is finite. The hydrologic cycle does have a natural ability to
purify water, but it cannot sustain itself against the current assault. Some
Canadian communities dump raw or minimally processed sewage into rivers,
and contamination from chemical and agricultural pollution adds significantly
to our water woes. Intensive development, increasing demand from industry
and growing cities, and even increased bottled water sales, all reduce the
quality and quantity of our water supply. After we consider that we must share
our water with millions of other plant and animal species, any idea you might
have that Canada has an abundance of fresh water should quickly fade.
Water is so essential to everyday life that we could not survive without it.
Because of this, some people claim that it is a human right to have access to
fresh, clean water. More than 1 billion people in the world do not have this
access. Canadians are indeed fortunate to live in a part of the world with a
water surplus. Recently, however, there have been some changes. The demand
for bottled water has risen sharply because many people are concerned about
the quality of tap water. A number of corporations have begun to turn water
into a commodity that can be privatized (taken out of the hands of government
control), so that they can suck up our water and sell it back to us. The World
Bank estimates the global water market is worth a trillion dollars. No wonder
water has become known as “blue gold.”
So who owns Canada’s water? Who has the right to extract it, divert it, or
sell it? Does Canada have an obligation to sell its water resources to those
regions in need? Or should we conserve this valuable resource for future
generations and needs within Canada? Opinions are sharply divided. The
following CBC Web site will give you an overview of the arguments on both
sides of the issue: <www.cbc.ca/news/background/water/>.
19. What is your opinion regarding the selling of Canada’s water resources?
Prepare a one- to two-page report outlining your position on the topic.
Your analysis should use supporting evidence not only from your research
but also from the knowledge you have gained about water throughout this
activity.
Copyright © Oxford University Press Canada 2009.