Water lot of water?
What physical and human factors affect
water supply?
Is supply and demand balanced in different
parts of the world?
Human influences on water supply and
demand
•
Humans affect the hydrological cycle at many
points of flows and storage:
By Quantity
Land use changes affect
interception +
infiltration + surface
storage;
Eg urbanisation,
deforestation
Flood management + dam
construction affect
channel flow + storage
( adding to or
abstracting) or
Quality(pollution)
Disruption
of water
cycle
Water abstraction
affects ground water
storage, and can
create salinisation
and salt water
incursion
Graphs p 34 and 35 Pearson
• How is water used on a
worldwide scale?
• How is water used in
the UK?
• Blue water flow is the visible part of the hydrological system: surface
flows and then recharging aquifers
• Green water flow is water intercepted, stored in soil and released by
vegetation by evaporation and transpiration
• Grey water is polluted water
Supply can be from:
 Surface sources
 groundwater sources
 In the UK 2/3 of supply is from surface and 1/3 from groundwater, with
regional variations.
• Freshwater is effectively a finite resource since only about 1% of
freshwater is easily available for human use.
• The water footprint indicates how much is required by consumers- and in
an increasingly globalised world, the footprint of someone in a country
like the UK will not be just local as so many products using water will have
been produced elsewhere!
The cost of everyday items
….in litres of water.
One sheet of A4…
One slice of bread…
One apple..
One cup of coffee..
One pint of beer..
One pair of leather shoes..
One packet of mixed salad
One bag of crisps..
One litre of milk..
One cotton tee-shirt..
One pair of jeans..
One 100g bar of chocolate..
One glass of wine..
The cost of everyday items
….in litres of water.
One sheet of A4…10
One slice of bread…40
One apple..70
One cup of coffee..140
One pint of beer..75
One pair of leather shoes..16,600
One packet of mixed salad..50
One bag of crisps..185
One litre of milk..1000
One cotton tee-shirt..2700-4000
One pair of jeans..10,850
One 100g bar of chocolate..2400
One glass of wine..120
Some key definitions p 61 Oxford and p 37 Pearson
Water
shortage
low level of water
supply relative to basic
needs.
•
measured
by annual renewable flows (in cubic metres) per head of
population, or the number of people dependent on each unit of water
Water
stress
often taken as less than
1700m3 per person per
year
•growing conflict between users and competition for water
• declining standards of reliability and service
• harvest failures and food insecurity.
Water
scarcity
supply of water per
person falls below
1000m3/year
•an imbalance of supply
and demand
Domestic
•a high rate of use compared to available supply, especially if the
remaining supply is difficult or costly to tap.
Physical
water
scarcity
reached when 60% of
river flows are diverted
for agricultural,
industrial & municipal
purposes; globally over
75% is now used
Physical water scarcity is shown by:
• Severe environmental degradation
•Declining groundwater and water allocation which favours some groups
over others.
•Arid and semi-arid areas are most at risk
Economic
water
scarcity
when less than 25% of
rivers are used, and
there is abundant
supply potential: water
does not reach the
poorest people
This is often due to political reasons and conflict: easiest to solve by low
technology solutions: small dams, water harvesting from roof tops etc. It is
targeted by NGOs like Water Aid
Thirst!
• http://www.youtube.com/watch?v=ewD4RfkYms
Water Supply In India
1.Monsoon Climate
Due to the movement of the
ITCZ
High pressure due
to descending air
Brahmaputra
Little supply Dec – May
Ganges
Monsoon June - Oct
Indus
2. Changing Discharge
in the Ganges, Indus
and Brahmaputra.
3. Geology
Aquifers in the
North = good
water supply
This varies seasonally due
to the Monsoon and snow
melting in the Himalayas
Low Pressure due to the
position of the ITCZ
Cherrapunji’s (in India)missing water?
LO: Why can’t we have water everywhere?
Why?
Water scarcity isn’t just
the fault of people
What are the physical and human reasons that water is an issue in
Cherrapunji, India?
Thinking
• http://articles.timesofindia.indiatimes.com/20
11-12-04/guwahati/30474076_1_drinkingwater-water-resources-wettest-desert
Watch the clip and read the
article…in pairs
• Complete a table of the physical reasons and
human human reasons why water supply in
Cherrapunji has changed
• Highlight where there are potential overlaps
between the two columns.
• Decide which of the reasons is the strongest
by scoring them in order (1 for most
important, X for least important. The
strongest reason gets the lowest score)
Factors affecting Cherrapunji
• Physical geography
– Monsoon climate – variability
– Saturation of ground – impervious
– Climate change?
• Human Geography
– Lack of dams – can’t harness variable supply
– Aquaculture, NOT agriculture
– Overpopultion
Yemen
• Sanaa, capital of Yemen, has no renewable
water. At 2,300m above the sea, the city
cannot use desalinated water and the only
solution could be to move the capital.
• Read p 38 Pearson
UK water supply
Let’s examine the reasons for the variation
in water demand and supply in the UK.
Estimated changes in demand for water
1990 - 2021
• Work out the estimated changes in different
regions of the UK
• Show this on the map after discussing with
your partner
• What are the advantages / disadvantages of
the methods used?
Areas of water surplus /water deficit
Using a range of Atlas maps and information,
annotate the outline map of the UK to help
identify the reasons why there is a water
surplus /deficit in the areas identified. Add as
much detail as you can around your map.
Water resources and climate change?
• P 38 Pearson
The key players who affect the supply
and demand for water?
The key players who affect the supply
and demand for water?
•
•
•
•
•
•
•
•
•
Water companies
Governments – national and state/local authority
UN, WTO and TNCS
Agriculture
Industry/business
Recreation/tourism
Domestic users
Charities
Nature conservation
California p 52-59 Oxford
Why are we doing this case study?
‘With reference to differing examples , explain how differing stakeholders views could
lead to water conflict’ (15)
‘Referring to examples, assessCalifornia
the potential
for water
p 52-59
Oxfordconflict in areas where demand
exceeds supply’ (15)
1.
2.
3.
4.
5.
Explain the physical controls on the supply of fresh water in California
(think about the climate, river systems and aquifers etc )
How is human activity affecting the water availability in California?
What are different key players likely views on the water issues in
California?
What are the environmental implications of supplying water to
California?
What are the economic implications of supplying water to California?
IN DETAIL 
Why will conflict arise
here ?
Las Vegas 1.8
million
Hoover Dam
7 states covered :
Wyoming / Colorado
New Mexico / Arizona
California / Nevada
Utah
Colorado
1 of the bread basket
states
Mojave Desert
Glen Canyon Dam
Salt water :
Pacific Ocean and gulf of
California
Phoenix – 1.5
million
residents
History of the Colorado Basin
• Colorado Compact 1922, allocated the water rights between the
different states
• 1920’s ‘law of the River’ divided the river into the Upper basin
states, who had responsibility to supply the lower states
• Over time new treaties have been signed and Mexico has also been
involved
• Now there is a ‘giant plumbing system’, with more than 10 major
dams to give water to over 30 million people
• Lots of the treaties were established in the 1920’s, since then
population, industry and climate here have all changed
Farmers
City Dwellers
Environmentalist and
recreationists
Indigenous Groups
Mexican People
US federal Government
US federal
Gov
Mexican
People
Indigenous
groups
Environme
ntalists
City
dwellers
Stakeholder and what
they think including
specific detail
Farmers
Complete the Conflict matrix, but also put in
their opinions in detail in the first column