water

Question 1

3 types of rainfall (brief)

Answer 1

1. orographic
2. frontal
3. convectional

Question 1

what is orographic rain

Answer 1

-when warm, moist air meets land of high relief (hill), the air mass is forced to rise above the hill.
-as it rises, it cools and moisture within it condenses to form clouds and precipitation

Question 2

what is frontal rain

Answer 2

-where 1 cold front and 1 warm front meet, the less dense, lighter warm front is forced over the top of the cold front
-this causes the moisture within to cool and condense, forming precipitation

Question 3

what is convectional rainfall

Answer 3

• land that has been heated by the sun heats up the air above it, which rises rapidly, until it rises high enough that it begins to cool and the moisture within condenses, which forms clouds and precipitation

Question 4

flows in drainage basin systems

Answer 4

-interception
-infiltration
-percolation
-throughflow
-surface run-off
-channel flow
-drip flow

Question 5

physical factors affecting drainage basins (brief)

Answer 5

-climate
-soils
-vegetation
-geology
-relief

Question 6

flooding case study - somerset levels

Answer 6

-caused by low-lying, reclaimed land w confluence of 2 major rives, valley surrounded by areas of high relief, rivers hadnt been dredged, unusually high precipitation
-600 homes flooded leading to displacement and villages becoming inaccessible due to flooded roads
-£200 million loss for tourism industry
-looting
-soil degradation due to leaching, reducing fertility and affecting crop yields long term

Question 7

flooding case study - Bangladesh

Answer 7

-caused by low-lying land, meltwater and deforestation from the Himalayas, heavy monsoon rains and increasing urbanisation
-30 million made homeless and 750 deaths
-airport, schools, hospitals and major roads flooded, reducing ability to receive and distribute int aid
-2.2 million acres of damaged cropland and $290 million worth of crops damaged, causing food insecurity and malnourishment
-increase in water-borne diseases such as dysentery and diarrhoea

Question 8

drought case study - Australia millenium drought

Answer 8

-caused by very strong el nino event causing lack of rainfall, climate change causing higher temps leading to more evaporation, and years of over-abstraction of groundwater sources
-crop failure caused yield to fall, increasing food prices as more had to be imported
-less energy generated through HEP, leading to higher energy costs and increased use of fossil fuels

Question 9

drought case studies - somalia

Answer 9

-caused by 5 consecutive failed rainy seasons caused by climate change, deforestation, overgrazing and soil erosion reducing the soils ability to retain moisture
-43,000 people died due to food crisis and famine (1/2 of them children under 5)
-migration from rural villages to border towns (300-400 ppl arriving per day)
-1.2 million displaced

Question 10

enso cycles - normal conditions

Answer 10

-area of low pressure over Australia/SE Asia and high pressure over S America pushing trade winds from East to West, causing warmer waters to build up near Australia, which evaporate and form (normal) precipitation

Question 11

enso cycles - La nina

Answer 11

-normal conditions becoming more intense
-more warm water pushed towards Australia/SE Asia, resulting in wetter conditions and flooding, and dry/drought conditions in S America

Question 12

enso cycles - El Nino

Answer 12

-main cause of drought in Australia/SE Asia
-weakening or reversal of trade winds to blow from West to East, leading to warmer waters being pushed towards S America and cooler waters (which produce less evaporation so less precipitation) build up around Australia/SE Asia
-increases risk of wildfires, food and water insecurity

Question 13

deforestation in the Amazon

Answer 13

-20% of forest has been destroyed for cattle ranching, agriculture for biofuels and soya beans, development of towns and roads, and logging
-less interception = less evapotranspiration = less in atmospheric store = less precipitation
-leads to increased risk of forest fires due to drought and more surface run-off, leading to severe flooding and mudslides, aquifer depletion due to less infiltration, soil degradation and erosion as minerals are washed away

Question 14

4 human impacts on drainage basins (brief)

Answer 14

1. deforestation
2. urbanisation
3. over-abstraction
4. reservoir and dam construction

Question 15

what is a river regime

Answer 15

shows difference in the discharge of a river throughout the year (seasonal variability) measured in cumecs