Download Lesson 1 water - SLC Geog A Level Blog

CONTESTED PLANET UNIT 3
Topic 2: Water Conflicts
Topics to be learned
• The geography of water supply
• The risks of water insecurity
• Water conflicts and the future
Water lot of water?
What physical affect water supply?
1 thing we
know
2 things we
think we
know
3 things we
want to find
out
2 things we
think we
know
3 things we
want to find
out
3 things we
want to find
out
What we know Triangle
1 thing we know
2 things we think we know
3 things we want to know
DM – June 2011
2 things we think we know
3 things we want to know
3 things we want to know
WATER QUIZ…
1. Water we use today is the same as has
been used for millions of years.
2. Which is the driest place on the earth?
3. What percentage of the world’s water is
fresh?
4. What percentage of the world’s water
is available for human use?
5. All of London’s water comes from the
Thames.
6. How much water is lost in the UK
through leaky pipes?
7. How much more rain do the wettest areas
of the UK get than the driest areas?
8. How many people in the world do not
have access to clean drinking water?
9. Which country uses the most water per
capita?
10. Water wars are conflicts between
countries across oceans.
1. Water we use today is the same as has
been used for millions of years.
The hydrological cycle
is a CLOSED system –
nothing enters, nothing
leaves…
2. Which is the driest place on the earth?
3. What percentage of the world’s water is
fresh?
4. What percentage of the world’s water
is available for human use?
5. All of London’s water comes from the
Thames.
We also obtain water
from AQUIFERS across
the south of England.
6. How much water is lost in the UK
through leaky pipes?
7. How much more rain do the wettest areas
of the UK get than the driest areas?
The Western Highlands get
500cm. East Anglia gets 50cm.
8. How many people in the world do not
have access to clean drinking water?
9. Which country uses the most water per
capita?
Turkmenistan has an arid
climate, a poor infrastructure
and inefficient usage.
10. Water wars are conflicts between
countries across oceans.
Water wars can occur
within a country e.g.
between states in the
USA. They are more
common between countries
e.g. Israel and Palestine.
Nerdy facts about water….
• 71% of the world is covered by water
• Only 0.0296% of the water on earth is used by humans
(rivers, freshwater lakes, ground water and soil store)
• If water was shared out equally amongst the 7+ billion
people on earth there would be enough for each person
to have 5 million litres
• But 4 billion live in areas with only 25% of the world’s
annual rainfall
• The UN says 1 billion lack access to fresh drinking water
• More than 0.5 billion face water shortages every day
• And the world population increases by approximately 80
million a year!
• Every 15 seconds a child dies from water
borne diseases
• Half of the world’s lakes and rivers are badly
polluted
• Half of the world’s rivers no longer flow all
year
• 12% of people consume 85% of the world’s
water
• Population growth by 2025 will demand a 20%
increase in water supplies
The risks of water insecurity
What are the potential implications of an increasingly ‘water insecure’ world?
Water supply problems
Increasing water shortages
may be more important than
energy shortages- because
there is no alternative!
Water transfers
Of this precious resource by either
diverting the actual river, or using canals
. Long carried out at a small scale but
increasingly over larger distances, and
even transboundary
Water conflicts
Where demand exceeds supply and
no effective management operates,
then there will be conflicts between
the various players involved
Water geopolitics
The conflicts between nation states,
despite the international agreement
called the Helsinki Rules designed to
create more equitable use of water
extending across boundaries
Do you know the terms of the
hydrological cycle?
- Closed System - Groundwater flow
- Stores
- Evaporation
- Flows
- River Flow
- Inputs
- Surface Runoff
- Outputs
- Through flow
- Blue water flow
- Green water flow
- Evapotranspiration
- Percolation
- Precipitation
- Infiltration
1.The geography of water supply physical
influences P 32-34 Pearson
Climate
a)
•Climatic zones are critical in determining water storage in any of then earth’s
reservoirs
•Annual temperature and rainfall patterns in a place determine the availability of
water
•Precipitation (rain, hail, sleet and snow) varies with latitude
•Equatorial/ tropical areas (up to 15 degrees N or S of equator) have higher rainfall
than temperate(40-60 degrees North and South) / arctic areas.
•High altitude areas have snowpack water reserves released in late spring.
•Monsoon areas have one main peak, equatorial areas two peaks.
•Other factors like proximity to oceans and prevailing winds distort latitudinal divisions
•Seasonality is of great importance in an area – eg in Vancouver Canada summer
evapotranspiration is higher than precipitation so there is soil moisture deficit but in
winter there is more precipitation than evapotranspiration so the soil moisture
increases and recharges……see graph in Pearson
•So location can determine the relative size of the input of precipitation and the
output by evaporation, transpiration, (as well as runoff to the sea/lake and
abstraction).
Monsoon Climate
El Nino
Climate
Global Climate Circulation
River systems transport this water.
• Discharge/flows increase downstream as tributaries enter.
• The time it takes from the peak precipitation to fall to reach
the peak river discharge (lag time) is determined by –
Type of precipitation
Antecedent (previous) rainfall
Land use
Size and shape of drainage basin
Relief of catchment
Drainage pattern
And geology
• The relationship between water inputs and outputs is water
balance
• Seasonal changes in temperature/precipitation can create
distinctive river regimes.
b)
River Systems
Discharge = Cross Sectional area x Velocity
This increases down stream
Streamflow can only occur when the water stores in the drainage basin are capable of releasing water, and
when there is direct surface runoff.
In order to understand the streamflow pattern across a year (called the river regime) you have to understand
the changing balance of three key variables – evapotranspiration, soil storage and groundwater storage.
This dynamic relationship can be expressed as the water balance equation:
Precipitation (P) = streamflow (Q) + evapotranspiration (E) +/- changes in storage (S)
River Regimes Vary and so does water
Supply
c) Geology
• Surface drainage occurs on rocks which are impermeable such as
granite and clay as they are aquicludes
• Permeable rocks like chalk and some sandstones store water, called
aquifers.
• The rate of infiltration of water into the soil or of percolation into
rocks depends on the porosity and permeability of the material. Sand
has large pores and this allows water to infiltrate quickly at a rate of
about 200mm/hr whilst in clay the rate is only about 5mm/hour. Both
materials are porous (the % of the material that is air spaces or pores)
but the sand is much more permeable.
• [Perviousness is where water can drain through cracks in the rock –
limestone is a pervious rock with many joints and bedding planes].
• Soil water is important because it affects upward and downward
movement of water (and dissolved nutrients). Drainage depends on
the balance between the water retention capacity (water storage In
the soil) and the infiltration rate. This is controlled by the porosity
and permeability of the soil. Clays have many micropores which can
retain water for long periods – giving it a high water retention
capacity but reducing its infiltration rate. Sands have fewer but much
larger macropores which permit more rapid infiltration.
Geology
1. Impermeable Rocks = High
Drainage density
2. Permeable rocks = water
passes under ground
3. Aquifers e.g chalk