Forced Migration Case Study: Zimbabwe to South Africa

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Hydrological Cycle Human Date Today I
will- Know how humans have an impact on the
hydrological cycle
The Hydrological Cycle is a natural process
however, humans can have an impact on the system
in various ways
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As I go through the PowerPoint add in the
relevant information to your mind map. Feel free
to add additional information from your summary
notes or textbook when you are finished.
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• Mining
• - Lakes, rivers and reservoirs silt up leading
  to reduced storage capacity in these areas.
• There is reduced vegetation cover which leads to
• increased run-off
• lower evapo -transpiration and cloud formation
  altering the rainfall pattern.

Mining for gold in the Amazon
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• Irrigation
• - It involves taking water from a river or
  underground store which can
• reduce river flow
• lower water tables

• It can increase evaporation/evapo-transpiration
  by placing water in surface stores
  (ditches/canals)
• Crops remove water from the cycle as they grow

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• Deforestation
• Cutting down trees increases run-off
• It decreases evapo-transpiration (and therefore
  cloud formation)
• more extreme river flows as water is not
  intercepted

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Urbanisation - The removal of natural vegetation
and replacement with impermeable surfaces and
drains can speed up overland flow and
evaporation and can lead to higher river levels.
- It also decreases the amount of water which
returns to groundwater storage, possibly reducing
the water table. - It requires taking water for
use in the cities which reduces water in rivers
(due to reservoirs) or groundwater (due to wells)

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