Geography A2 - Water Security
- Created by: Ellaflies
- Created on: 29-05-17 18:49
Geography A2 water notes
INTRODUCTION
· 97.5% of the worlds water is in the sea - difficult to use
· 2/3 population only recieve 25% of the rainfall
· Water gap - MEDCs use 10 times more water than LDCs (More money, more supply and more usage. LDCs dont have the water so it is more expensive)
· By 2025 half of the population expected to be water vulnerable
· international rivers
transboundary groundwater
shared between 2 or more countries
upstream gets dammed
Leads to conflict
· BRICS/NICS developing - disposable income increases
Industry needs more water
want more tech - use more water
· some people dont have enough clean water
· Climate change - melting glaciers and little room for LDCs to adapt
· humans are polluting fresh water
· LDCs one of the biggest killers are waterbourne diseases
Physical Factors that influence water supply
· Climate determines the global distribution of water by means of annual and seasonal rainfall distribution or snowfall
· Rivers transfer surface water across continents
· Geology controls the distribution of aquifers which supply underground water
TYPES OF RAINFALL
· Convectional rainfall
In the Amazon rainforest where the sun is overhead, it has a high angle in the sky which means you get convectional rainfall = 2000mm rain per year
UK = 800/1000mm rain per year.
· Relief rainfall
Areas of Highland, eg: west of the UK
Air warms up and contains little moisture
rain shadow effect (dry conditions)
· Intertropical
What causes drought?
· Problem for water supply
· El Nino in Australia and La Nina in S America
· Rain Shadow effects
· Wind From Land
· High Pressure
How do Humans Interfere with the Water Cycle?
Process
Definition
Human interference
Evaporation
When water turns into vapor and goes up to the clouds
Climate change
Transpiration
Evaporation of water from pores (stomata) of plants
Deforestation
Reduce rainfall
- Plant trees
Precipitation
Water and ice that fall to the earth’s surface
Climate change
Infiltration
When water is soaked into the ground
Make impermeable surfaces
Surface runoff
Water running offsurface because it is impermeable
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Groundwater
Water stored in the ground
Overpump the ground water (salt water incursion) and pollute it
Physical factors affecting water sources -
Climate
· How rainfall varies globally
· Regions near to the equator recieve high levels of annual precipitation while some tropical areas suffer reoccuring drought
River systems
· River flow generally increases downstream as tributaries feed into the main river
· Though high temperatures can lead to considerable water loss due to evaporation
Geology
· Where rocks underlying river basin are impermeable water will remain…
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