Key terms
Key term
Definition
Hydrosphere
All the water stored on the Earth’s surface and in the atmosphere.
Hydrological Cycle
The cycle of water transfers and stores around the hydrosphere.
Evaporation
When liquid water is converted to water vapour due to heat.
Condensation
When water vapour cools and turns back into liquid water.
Precipitation
When water stored in clouds falls to Earth as rain, snow, hail or sleet.
Transpiration
When water is evaporated from the leaves of plants and trees.
Surface water
Water stored on the Earth’s surface, for example in lakes and ponds.
Surface runoff
Water flowing along the Earth’s surface, for example in rivers.
Groundwater
Water stored in the ground, for example in aquifers.
Groundwater flow
Water flowing through the ground, for example in underground
rivers.
Infiltration
When water soaks into the ground
Percolation
Water flowing downwards through soil and rock
Transfer
Processes where water is being moved from one store to another
Store
When water is being contained in one place
Key terms
Key term
Definition
Drought
A prolonged period of abnormally low rainfall, leading to water
shortage.
Seasonality
Changes relevant to specific seasons.
Water stress
Pressure on water supply
Desert
An area experiencing under 250mm of rainfall per year.
Desertification
When previously fertile land is changed to desert
Eutrophication
Excessive nutrients in a lake or river, which leads to growth of algae.
Nutrient overload
An oversupply of nutrients, leading to eutrophication.
Algal bloom
A large growth of algae on the surface of a body of water.
Overabstraction
Taking too much water from the ground.
Irrigation
The supply of water to crops.
Intermediate
technology
Technology appropriate to the people using it, making use of locally
available resources.
Key facts: The hydrological cycle
Key facts: The hydrological cycle and
climate change
Key facts: Water pollution sources
Industrial:
• Warm water from power
stations
• Acidic gases dissolved in
water
• Chemical waste
• Heavy metals e.g. lead
Domestic:
• Sewage from homes
• Litter
Agricultural:
• Chemicals from pesticides
and fertilisers
• Animal waste and manure
Transport:
• Emissions from boats and
ships
• Oil from engines
• Litter from tourists.
Key facts: Eutrophication
Key facts: Causes of eutrophication
Named example of climate change and the
hydrological cycle: South East Australia.
http://www.youtube.com/watch?v=u9s_A0G7oUU
http://www.youtube.com/watch?v=B5MuR_FvEvA
• 2007 – worst drought for 1,000 years.
• Reduction in levels of the Murray River – decreased
irrigation and crop failure
• Increase in bush fires
• Wheat yields have fallen by half
• Winemakers being put out of business
• Ecosystems are suffering
Named example of an unreliable water supply:
Somalia drought, 2005-6
Location:
East Africa, on the Indian Ocean
coast. Bordering Ethiopia and Kenya
PHYSICAL causes:
• Failure of annual monsoon rainfall
• Some areas received as little as 10%
of average rainfall for the time of
year
HUMAN causes:
• Deforestation, disrupting the water
cycle
• Rapid population growth –
pressure on water supplies
• Past conflict means little
investment in water supplies
Effects:
• Crop failure
• Dehydration and malnourishment
• People made homeless and become
refugees
• 11.5 million people in need of food
aid
• Wells run dry
• Death of livestock
Named example of an unreliable water supply:
desertification in The Sahel
Location:
A narrow band immediately south of
the Sahara desert , stretching from
west to east Africa
PHYSICAL causes:
• Naturally dry climate with
prolonged drought
• Persistent high temperatures
• Dry, loose soil eroded by wind
• Naturally low water table
HUMAN causes:
• Overgrazing by cattle, exposing
loose soil to erosion
• Deforestation
• Overpopulation, leading to
overabstraction of groundwater
Effects:
• Exposed soil is easily eroded,
leading to fewer nutrients
• Crops are therefore unable to grow
• Biodiversity is reduced – animals
dry out
• Land eventually becomes a desert
as the process repeats.
Named example of reduced water quality: The
Rhine
• Various sources of pollution (see
slide 6)
• One of the world’s most heavily
industrialised rivers
• 1986 Sandoz chemical disaster at a
chemical factory fire in Switzerland
led to disastrous levels of pollution
• Caused by runoff from hoses of
firefighters, which washed chemicals
into the river.
The Rhine Action Programme was put
in place to restore biodiversity and
reduce levels of pollution.
Named example of overabstraction of
groundwater: Benidorm
Location:
• South East Spain, on a stretch of coast
known as the Costa Blanca.
The issue:
• Benidorm is one of Spain’s main tourist
resorts
• Water is being abstracted fromt he ground
to cater for tourist needs e.g. Swimming
pools and golf courses
• Water is being removed at a rate 2-3 times
quicker than it can recharge
• Water is now being piped in from the River
Tajo, 400km away
Effects:
• Sea water is soaking into the soil near
coastal areas, poisoning the groundwater
supply and causing crops to fail
• Subsidence due to falling water levels,
damaging buildings
Named example of diversion of river channels:
The Aral Sea
• River channels feeding the Aral Sea diverted by the Soviet Union to
irrigate cotton fields
• Lake level has decreased by 90%
• Salinity of water has increased, poisoning fish and affecting fishing
industry
• Ports have shut down and are now located miles from the lake
• Wind blows dust polluted with chemicals from the lake into towns,
reducing life expectancy
Named example of overabstraction and
damming of rivers: The Colorado River, USA
Causes:
• Growth of cities such as Los Angeles,
Las Vegas and Phoenix
• 10 major dams built along the river,
disrupting flow
• Increased irrigation due to higher food
demand
• Inappropriate irrigation leads to high
water wastage
Consequences:
• Reduction in lake levels, such as Lake Mead
• River often dries up before it reaches the sea, causing political tension between the
US and Mexico
• Lakes become more saline, damaging biodiversity
Named example of large-scale water
management (LEDC): The Katse Dam, Lesotho
Purpose is to supply water to Johannesburg, South Africa and to provide income for
Lesotho
Positive - Lesotho
• Source of income for the country. South
Africa pay for water supplied by the dam
• Provided jobs in construction and
maintenance of dams
• Provided workers with new skills
Positive – South Africa
• Provided water to Johannesburg, often
to poor neighbourhoods which
previously had a poor water supply.
Impacts
Negative - Lesotho
• Flooded farmland, reduced income for
farmers.
• Local people did not directly benefit
from the income from the dam.
• People forced out of homes to make way
for dams and reservoirs
Negative – South Africa
• Cost of dam and transport of water
meant increased water bills for the public
and taxes to pay for the scheme
Named example of large-scale water
management (MEDC): The Snowy Mountains,
Australia
Purpose is to divert water from the Snowy Mountains for use in agriculture and
energy generation, then to be diverted back into the Murray river
Benefits:
• Has allowed the development of
farming along the Murray river.
• Provided employment to over
100,000 people.
• Energy produced, and water
supplied, by the scheme, has
allowed cities like Sydney to develop
and improve their economies.
• Plays a vital role in the growth and
the development of Australia’s
economy. Crops produced die to
irrigation from the scheme are
worth around £1billion.
Problems:
• Creation of storage lakes has
destroyed valuable wildlife habitats.
• Record droughts in recent years
have meant that the scheme is
working well below its intended
level.
• Flow of the Snowy River has fallen
to 1% of its original level.
• Water in the Snowy River has
become more saline (salty),
affecting farms further downstream
in the Murray floodplain.
• Issues between farmers and city
dwellers, competing for falling
water supplies.
Named example of small-scale water
management: WaterAid (Tanzania)
How does WaterAid operate in LEDC’s?
WaterAid
supply the
technology,
information
and advice
Result:
A sustainable,
clean
water supply.
WaterAid
works through
local partners.
(Local NGO’s/
charities
in the area)
Some villagers
are trained
to look after
the well
and carry
out repairs.
Villagers
liaise with
the local NGO. Then
form a committee
to decide where the well
will go and organise
the work.
The well is built
by the villagers,
using appropriate
technology
that they
are able to
maintain.
Named example of small-scale water
management: WaterAid (Tanzania)
IMPACTS:
• Increased irrigation for crops, leading to increased
incomes for farmers
• Reduction in water-borne diseases, such as cholera
• Children spend less time collecting water, meaning
that they can go to school (paid for by increased
income)
• Women spend less time collecting water, allowing
them to spend more time focusing on growing crops
Past GCSE questions
Explain how water is transferred from the land to the atmosphere in the hydrological cycle. (4 marks)
Describe how water is transferred from the oceans to the atmosphere and back again (4 marks)
Outline the process of precipitation. (2 marks)
State two impacts of deforestation on the hydrological cycle. (2 marks)
Describe one impact of water shortages on people. (2 marks)
Describe two impacts of water shortages on people. (4 marks)
Outline why an unreliable water supply can cause problems for farmers (2 marks)
Using examples, describe how human interference can disrupt water supply. (4 marks)
For a named vulnerable area, describe one problem caused by an unreliable or insufficient water supply. (2 marks)
Describe how one human activity can result in a decline in water quality. (2 marks)
Describe two ways in which human activities can affect water quality (4marks)
Give two effects of water pollution (2 marks)
Using an example(s), explain why small scale solutions (intermediate technology) to managing water supplies are often
sustainable in the developing world (6 marks)
Using an example(s), explain why small scale solutions to managing water supplies are often sustainable. (4 marks)
State two ways of using intermediate technology to manage water resources (2marks)
Using examples, examine the costs and benefits of large-scale water management schemes. (6 marks)
Describe the costs and benefits of a named large-scale water management project. (4 marks)
For a named water management project, describe ways it has benefitted local people. (2 marks)