WC 2.1.5- Deficit in the water cycle Flashcards
define deficit (drought)
of period of time where there is below average precipitation resulting in prolonged shortages of water supply
define what is meant by meteorological causes
atmospheric and weather related causes that lead to a specific climate
What are the 5 meteorological causes of drought (including seasonal variation and long term climate change)
prolonger periods of H _
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- prolonged periods of high pressure
- increased atmospheric temperature (climate change)
- Atmospheric circulation
- Monsoon seasonality
- ENSO cycles -
what are the other natural causes of drought (4)
- Rain shadows (orographic belts)
- Continentality (how far away from the sea you are)
- ocean temperatures (cold ocean currents and not hot, so no evaporation occurs, meaning there’s no clouds formed for it to rain- causing drought)
What is the main human cause of deficit (water demand exceeds the water supply)
Humans have caused water deficit from doing ‘water abstraction’
This refers to the process of extracting water from a natural source (lake, aquifer) and using it for various things such as irrigation or industrial applications
What 2 things does water abstraction lead to
depleting: meaning a reduction of a resource overtime
- Depleting surface water e.g. lakes, reservoirs, wetlands
- Depleting ground water stores e.g. aquifers
what are the 3 reasons why there is depleting surface and ground water stores
- agriculture use (farm, vegetation/ animals, cotton production)
- Domestic use (cooking, keeping clean-showers)
- Industrial use (machines, washing and dying clothes, energy production)
explain the causes of humans creating deficit
example 1: The Aral Sea
The Aral Sea
causes:
- 1960’s soviet union diverted 2 major rivers (Syr Darya and Amu Darya) onto the arid plains of kazahstan and Uzbekistan for cotton production.
- It was a closed basin so water was sources from rivers (fed by snow-melt and precipitation) but had no outlet to the ocean, this meant that the water could only evaporate, leaving the salty minerals behind increasing it’s salinity overtime
explain the consequences of humans creating deficit
example 1: The Aral Sea
the consequences are:
1. Ecosystem Collapse
2. Salinity Increase- As the sea shrinks, the salinity increases- restricting species that can survive in the lake, leading to a decline in biodiversity.
3. Desertification- altered local climates and reduced vegetation in surrounding areas.
Health Consequences- increased rates of respiratory diseases
4. Economic Decline- collapse of the fishing industry
What have they done to try help the loss biodiversity in example 1- Aral Sea
The built a dam to help the fish rebound
which was a success
Explain the Causes of humans
creating deficit
example 2: coca cola in India
2019- India had an ongoing drought which threatened the supplies of groundwater across India.
Coca cola had 58 water intensive bottling plants which was accused of causes the droughts from the depleting water source as they extracted too much out
Explain the consequences of humans creating deficit
example 2: coca cola in India
As a result of the 58 bottling plants, residents had to rely on the daily trucks from the government due to the dried up groundwater storage
- contaminated sludge from the factories was given out to the farmers as ‘free fertiliser’
Explain the Causes of humans creating deficit
example 3: Panama canal
The panama canal is a shortcut used by container shipping to get from the pacific to the Atlantic
This canal dried up and a cause being it was dependent on freshwater from a man-made lake
Due to climate change, this year had the least amount of rainfall since 1950
Explain the consequences of humans creating deficit
example 3: panama canal
A consequence of this drought was that it meant that the amount of ships going through was reduced,
Creating a queue of container ships in the the pacific
costing the ships time and money
Explain the Causes of humans creating deficit
example 4: Day zero, cape town
cape towns supply of water is from a dam.
This dam has been decreasing in water supply since 2015
2018 it was 10%full
Explain the consequences of humans creating deficit
example 4: day zero, cape town
this meant that the residents are restricted to 50 litres per day
name the two types of aquifers
- Natural recharge
- Artificial recharge
explain what a natural aquifer recharge is
Natural aquifer recharge is from water supplied from precipitation, river bed seepage, flooding
- which enters the groundwater system
explain what is an artificial aquifer recharge is
an artificial aquifer recharge is the enhancement through human intervention of a natural groundwater system
give examples of a human invention thats created for artificial aquifer recharge
- infiltration (percolation) basins/ basin percolation- a small scale reservoir/ water impounded in a tank, parallel to stream channels
- field flooding
- infiltration galleries
- injection wells
- stream augmentation
- contour band - small embankments constructed along contour in a hilly region to retain surface run off for a longtime
to maintain natural aquifer recharge
list the 5 factors that are encouraged
reduce deforestation
reduce urban sprawl
reduce flood plain development
manage water courses
change land use to allow natural infiltration
what human intervention can help aquifers recharge
-spreading surface water to increase soil infiltration and prelocation to the aquifer
name one advantage of aquifers
they don’t take up land use because they are underground
