The Water Cycle Flashcards
Where is the source and mouth of the Amazon?
Source - Andes.
Mouth - Atlantic Ocean.
What water processes are high here and why?
Interception and evapotranspiration rates are high due to the amount of vegetation, which leads to humid weather and heavy conventional rainfall. Water can be recycled.
How much of intercepted water is returned to atmosphere via evapotranspiration?
75%
What percentage of the Amazon has been deforested?
20%.
What impact has deforestation had on the Amazon?
Decreased interception and evapotranspiration rates. Less photosynthesis and poses a threat to human life. As the Amazon becomes drier, the forest becomes degraded and leads to droughts and fires. Aquifer depletion increases as there is less water to replenish them.
Mining agriculture and deforestation leaves soil exposed, so nutrients are leached. This means mercury runs off into rivers = increased malaria rates.
What is the cause of the Sahel drought?
Since the 1960s, there has been a decline in rainfall. Almost all the rain is concentrated in the summer.
Warm sea surface temperatures favour strong conventional uplift over the ocean that weakens the monsoon = drought.
Air pollution from Europe + America cooled the Earth + prevented tropical rain moving north.
What were the impacts of the Sahel drought?
The 1998-2000 famine in Ethiopia led to 10 million needing food assistance.
The nomadic communities experienced encroachment of farmland.
Poverty and civil war led to people moving out of cities to rural areas, increasing the pressure of limited food.
What are the causes of Australian droughts?
El Niño.
Shift in rain patterns from West -> North.
Droughts can be long/short.
Low rainfall there due to the climate being dominated by the subtropical high-pressure belt of the southern hemisphere.
What was the cause of the ‘Big Dry’?
Surface/ground water resources were over-extracted. (Other factors too).
What were the impacts of the ‘Big Dry’?
Affected more than 1/2 the farmland = impacts on food/cotton supply.
Reservoirs fell to 40% of their capacity in 2016.
Desalination schemes were created as well as large scale grey water + sewage recycling.
Water conservation strategies created.
What was the cause of the 2007 flooding?
For the 3 months before July, 387mm of rain fell which is more than double the average (186mm).
Wettest July on record.
Rainfall along the river Severn had reached record levels and then a storm led to the flooding.
What were the impacts of the 2007 flooding?
Dozens were killed and costs were £6million.
At Shrewsbury, flood flow was 6 times normal - flood defences helped.
In Tewkesbury, Gloucestershire houses were flooded.
What was the cause of the Pakistan 2022 flood?
Monsoon rain: it occurred due to a 784% increase in rainfall above Augusts average. Hotter water temperatures.
What were the impacts of the Pakistan flood 2022?
1739 people died.
33 million affected.
$40 billion damage.
1/3 of the country was underwater.
What were the causes of Storm Desmond?
Large amounts of rainfall. Cumbria received 341mm of rain in 24 hours.
What were the impacts of Storm Desmond?
£500 million in damage across Cumbria.
1000 people were evacuated.
50000 people were without power.
40 schools were closed, NHS/doctor appointments were cancelled.
What were the responses to Storm Desmond?
100 flood warnings and 70 flood alerts were put in place.
£400000 was donated by the public.
What happened in Bolivia in relation to water?
In 1999 it was privatised, meaning it became more expensive however the quality did not improve. The price ended up being cut.
Everyone in Cochabamba went on strike - 12 died and the company left.
What are the causes of California’s water insecurity?
They use more water than any other US state - 181 gallons each day (US average 80-100 gallons).
Used for irrigation (60%).
In 2010, Californians withdrew 38 billion gallons a day, in 2005 it was 46 billion a day.
16% is for public supply.
Their water needs are mainly met by snow melt hydrology.
What are the impacts of California’s water insecurity?
In 2014, the state governor declared a drought state of emergency and cut water use by 20%.
Their reservoir was at 27% capacity.
What were the factors affecting supply of California’s water insecurity?
Population growth - 2 mn -> 37 mn.
Average precipitation of 200-500mm.
Mountains prevent moist air reaching inland.
What were the causes of the Aral sea’s water insecurity?
From the 1930s the planners started to build canals to take water from the 2 main rivers to develop irrigated cotton and rice farming in the area.
In the 60s, more irrigation canals were built and up to 70% of irrigation water leaked/evaporated out of the canal so less water was flowing to the Aral Sea and began to shrink.
What were the impacts of the Aral sea’s water insecurity?
Sea fell by 20cm in 10 yrs and in the 80s, fell by 80-90cm per yr.
Sea split into North and South.
By 2004, surface area was 1/4 of its original size.
Became very salty = less fish = unemployment of 40000 people in the fishing industry.
People moved away.
Toxic dust from chemical residues on cotton led to an increase of respiratory diseases.
Loss of biodiversity.
What changes occurred to the Aral Sea?
In 2003, government used money from oil exports to build a dam.
It separates the 2 halves of the sea.
Completed in 2005, allows water levels in North Aral to increase as freshwater flows in but not out. This has increased water level by 10 metres and salinity decreased.
Fish returned.
