Water Scarcity Flashcards
What is water scarcity?
When the demand for clean fresh drinking water exceeds available supply
What are the three main ways of measuring water scarcity?
Absolute scarcity
Physical scarcity
Economic scarcity
What is absolute scarcity?
Water supply <1000m*3 per person per year
What does demand depend upon?
Climate
Economic growth
Life styles
What is water stress?
When more than 40% of a country’s river flows are being used
What is water scarcity in terms of river flow?
More than 75% of a country’s river flows Rae being used
What is physical water scarcity?
When a country is using nearly all of its blue water with little spare
What is economic water scarcity?
when the development of the water resources is limited by human and financial capacities
cant afford to access water
what is an example economic water scarcity?
1 billion people in LEDCs use less than 25% of river flows and as a result are short of clean water
what are some causes of insecurity?
physical (climate variability)
human (water contamination from industry or agriculture, over absraction)
howmuch water does our agricultural water supply use?
uses 74% of the worlds water supply
why is irrigation wasteful?
water usually lost via transpiration and run-off making reuse impossible
what agricultural pollution can reduce river quality?
pesticides
fertilisers
how much water does industry use?
18% of the global water supply
more effcient than agriculture and water can be recycled
how much water do domestic sectors use?
8% of global supply
huge variations between countries
most rapidly growing sector
what % of the worlds freshwater does India have?
4%
what % of the world popualtion does India have?
16%
what happned to India in 2020? (Water)
demand exceeded supply in 2020 and water tables are falling rapidly
why has demand exceeded supply in India?
increasing population levels
issues of increasing industrialisation (coca cola)
what % of the worlds freshwater does china have?
8%
what % of the worlds populaiton does china have?
22%
what % of chinese cities do not have enough water all year round?
66%
what do china have to do for cities that dont have enough water year round?
they have to transport water in
what % of china’s freshwater is contaminated by heavy metals?
60%
what has the contamination of freshwater with heavy metals meant for china?
rates of liver = stomach cancer more than double that of the rest of the world
how much industrial waste does the worlds create each year?
400 billion tonnes
what sort of heavy metals are most likley to end up in rivers?
lead
cadmium
mercury
what does the addition of heavy metals to rivers affect?
reduces water quality affecting native species
what is abstraction?
removal of water from rivers and ground water sources
what is the problem with global absraction of water?
absracted from aquifers faster than it can be replaced
what areas are aquifers very unlikely to be recharged?
in arid areas (california)
what are the demands for water in california?
40 milllion people (10% of water usage)
80% of californias water is used for growing crops + farming animals
what is californias biggest export?
Almonds
what is the problem with almonds as an export?
very thirsty crop ( uses 10% of californias water)
where does most precipitation occur in california?
occurs in the mountains of the north - 1360mm/yr
what supply vs demand problem does california face?
supply 75% in the north where only 20% of population live
how much does californias supply vary?
40%
why does californias supply of water vary?
depends on the weather
highly vulnerable to climate change
when did the mega drought occur in california?
2000-2022
22 years
what % are reseviors at compared to usual? (California)
25% capacity
How much snowmelt is there compared to normal in california?
38%
what is the reduced snowmelt caused by in California?
La Nina
what is california an example of?
a rich area that is still understress
what is salt water intrusion?
the movement of saline water into freshwater aquifers
what has a higher density sea water or freshwater?
sea water as it carries salt
how does saltwater incursion occur?
- when freshwater is withdrawn faster than it can be replaced the water table is drawn dwn
- reducing pressure
- if this happens near coastal areas saltwater from the ocean is pulled into the freshwater aquifer
