Drought

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Drought

• S4 Climate

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Drought in the UK
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Task

• Why was there a water shortage in much of England
  and Wales during 1995? (1)
• What effect did the drought have on rivers and
  reservoirs? (1)
• What difficulties did this pose to authorities
  and what methods did they employ to overcome
  them? (3)
• Extension work section 7 pp229 b and c

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Water supplies and transfers

• While the UK receives more than enough rain to
  meet demand much of the rain falls when and where
  it is least needed.
• Our increasing dependence on aquifers means that
  despite the recent flooding in England water
  authorities are predicting significant water
  shortages by 2021.

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Drought in the developing world

• While there is more water than land on earth, 97
  of it is found in the oceans and 2 is stored as
  ice and snow. The remaining 1 is constantly
  recycled in the hydrological (water) cycle it is
  a closed system thus can be regarded as a
  renewable source.

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So why do 1.5 billion not have enough?

• While in the last 3000 years the population has
  increased 7 times the demand for water has
  increased by 35 times.
• In addition to an increased demand in water
  there has been an increase in its pollution
• It is estimated that 25000 people die a year form
  using contaminated water.
• By the year 2050 is is estimated 5 billion people
  will experiencing severe water stress.

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Reliability of rainfall

• Unlike Britain developing countries often have
  very clear wet and dry seasons. Some years the
  rain doesnt fall at all which can have very
  serious effects on crops, animals and sometimes
  people. The most vulnerable areas are at the edge
  of deserts and inner tropical areas which usually
  have very little rainfall anyway. In these areas
  even a drop of only 10 in annual rainfall can be
  critical.

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Task copy this into your jotter

• When the rain does come it is often less
  effective than that in Britain, this is because
  when the rain does come it is usually in a
  torrential downpour which doesnt have time to
  penetrate the baked hard ground. So instead of
  sinking into the soil it flows over the top
  instead causing flash floods.
• The developing countries also have less money to
  spend on building dams etc to store water.
• Extension What problems are involved if the
  country borrows money to build such projects.

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Clean water

• It is estimated that 1500million people
• lack a satisfactory or safe water supply.
• In developing countries rural streams
• used for drinking
• May also be used
• for the disposal
• of sewage.

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• In urban areas especially in the shanty towns
  the absence of drains can also mean that
  untreated sewage contaminates water supplies and
  the problem is made worse because of the large
  number of people contributing to the problem.

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(No Transcript)
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• What is being done to help
• Despite efforts by the UN 50 of people in rural
  areas do not have adequate drinking water. Most
  of the work was carried out by charities like
  Oxfam, action aid etc and included self help
  schemes such as digging and lining wells to tap
  and protect permanent underground supplies.

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Copy this into your jotters

• Governments often do not legislate against the
• pollution of water courses this leads to not only
• the loss of a renewable resource but can also
• lead to the outbreak of disease such as cholera,
• typhoid, dysentery and diarrhoea. Many of the
• people in developing countries lack the funds for
• medical treatment to these diseases and so many
• people may die.
• Extension Why are self help schemes often more
  suitable than large schemes financed by overseas
  countries?

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Desertification

• The desert areas of the world are getting larger.
  Each year an area the size of Denmark is turned
  into desert.
• While climate change can account for some of this
  the majority of the blame lies with humans
• Drought, gathering firewood, growing millet
  without manure, and new water holes

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How does it happen

• The sand dunes DO NOT creep across the land, it
  is more like a cancer. At first small areas lose
  soil through over grazing, or the removal of
  trees/bushes.
• These areas grow larger and eventually join
  together to form new desert.

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• Over the past 50 years the population of the
  Sahel has grown quickly. This means there is
  increased pressure on the already limited
  resources. As well as an increase in native
  population war in surrounding areas means the
  area often receives refugees with no place else
  to go.

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Task

• What is desertification
• Describe the effects of a) drought, b) gathering
  firewood, c) growing millet without manure, and
  d) new water holes
• Explain why the phrase live as if youll die
  tomorrow but farm as if youll live forever make
  sense?