The water cycle and water insecurity EQ 2

Question 1

Define drought.

Answer 1

A creeping hazard that causes a period of abnormally dry weather in a region causing a significant unbalance in the local water cycle leading to water insecurity.

Question 2

What are the four different types of drought?

Answer 2

Meteorological drought - lack of precipitation
Hydrological drought - when visible water sources dry up e.g streams and lakes.
Agricultural drought - when soil moisture deficit
Socio-economic drought - food deficit or famine due to failure of crops.

Question 3

Changes in drought patterns

Answer 3

Areas that are severly affected by drought has doubles in the last 30 years to include more than 30% of Earths terrestrial land.
Areas affected include Southern Europe, Canada, Asia and Western Australia.

Question 4

Drought in the Aral Sea.

Answer 4

The Aral sea is now only 10% of its original volume.
One of the largest problems is tributaries being diverted to water farmland to water cotton crop to fuel growing clothing industry.

Question 5

What are the three different measurements of drought?

Answer 5

Palmer Drought Severity Index - used for long term drought, looks at the duration and intensity of atmospheric conditions associated with drought.
Crop Moisture Index - used by farmers during the growing system to quickly detect short term agricultural drought.
Palmer Hydrological Drought Index - used to look at the impact of drought on local hydrological systems.

Question 6

Why does the western USA suffer more drought than the east?

Answer 6

Large mountain ranges such as Appalachian and Rocky Mountains divide the east and west.
Air masses arrive from the Atlantic on the eastern coast, air masses rise on the eastern side of the mountain causing orographic rainfall.
West falls in the rain shadow
Virginia 44 inches of rain a year
California 31 inches of rain a year.

Question 7

What do synoptic weather charts show?

Answer 7

Movement of low and high pressure air masses.
domed = high pressure pointed = low pressure
Isobars = mark areas of equal pressure.

Question 8

What happens at areas of low pressure?

Answer 8

Warm air evaporates and rises.
Then condenses causing precipitation.
E.g tropics

Question 9

What happens at areas of high pressure?

Answer 9

Cold air sinks
Often blue skies, dry, lack of precipitation
e.d deserts.

Question 10

What is the ITCZ?

Answer 10

The inter-tropical convergence zone.
Low pressure belt near the equator that migrates with the changing position of the thermal equator due to Earth’s tilt on its axis.
When it is directly above their is intense evaporation from the suns heat causing rapid precipitation.
Its movement causes wet and dry seasons.

Question 11

Where is the ITCZ in July v January?

Answer 11

July - Guatemala, El Salvador, Libya, Egypt, Saudi Arabia, Northern India and Northern China
January - Brazil, DRC, Mozambique, Indonesia

Question 12

Briefly explain patterns of the Global atmospheric circulation model and weather patterns.

Answer 12

Cells: Polar, Ferrel and Hadley.
Hadley Ferrel Boundary - high pressure - deserts 30 to 50 degrees latitude.
Ferrel Polar Boundary, hadley hadley boundary - low pressure zones 0 degrees is the tropics 60 degrees low pressure UK

Question 13

How does mid latitude blocking anticyclones cause drought in mid-lattitudes?

Answer 13

Frontal rainfall occurs at low pressure or depressions.
The track of depressions in the northern hemisphere is controlled by the polar jet stream, a fast moving mass of air in the upper troposphere.
Occassionaly the jet stream decreases in speed or breaks up.
This allows high pressure anticyclones from the subtropics to move northwards.
Anticyclones bring stable weather pushing out rain-bearing depressions causing drought in mid-lattitudes.

Question 14

What are ENSO cycles?

Answer 14

Term used to describe a variation in atmospheric and ocean temperatures in the South Pacifc Ocean between western Australia and South America.
Can cause complex weather patterns for 9-12 months
El NIna _ exaggerated normal (wet AUS dry SA)
El Nino - Opposte conditions (dry AUS wet SA)
Occurs every 3 to 7 years.

Question 15

What causes an El Nino year?

Answer 15

Air pressure over West Coast of America becomes high as the water becomes warmer and evaporates.
Air pressure over Australia becomes low as colder water.
This causes trade winds to change direction and blow west to east.
Pushes warm water to South America.
Causes drought and negative water budgets in Australia.
Causes flooding and positive water budgets in South America.

Question 16

What climate hazards are associated with El Nino?

Answer 16

Australian bush fires - March 2020 18.6 million hectares burnt.
Between 2002 and 2009 western Australia received its worst drought in 125 years due to ENSO cycles.
Teleconnections - caused Dry, warm conditions in Indonesia and souther Africa.
- caused wet conditions in western Europe and Southern USA.
In 2016 during an El Nino event drought was exacerbated in Africa, in Ethiopia 4/5 crops failed and 2 million children suffered worsening maluntrition.

Question 17

Humans mainly cause deficits in the water cycle by…

Answer 17

Pollution : makes a water source unsuitable for use

Over-abstraction: taking too much water from water stores leading to depleting supplies

Question 18

The Sahel drought overview

Answer 18

Sahel in semi-arid
located at 19 degrees latitude, suffers from desertification
Vulnerable to drought because economy relies on cotton and millet crop outports to the rest of Africa.

Question 19

Physical causes of drought in the Sahel

Answer 19

Average temperatures of 29 degrees and only 250-500mm of rainfall a year
85% of rainfall is in the summer, lack technology to store water and high temperatures cause rapid evaporation

Question 20

Human causes of drought in the Sahel.

Answer 20

Around 80% of drylands in the Sahel have suffered from land degradation due to over-cultivation and cattle ranching, decreases soil moisture capacity - agricultural drought.
Increase in kerosene prices has caused a demand in deforestation for fuel wood, 90% of wood is used as fuel wood, catalyst for soil erosion.
Destruction of crop land due to civil war
95% of agriculture is rainfed - vulnerable
In 1995 40% of sub-saharan countries were in debt, limited finance for investment in local water schemes.

Question 21

Impacts of drought in the Sahel.

Answer 21

100,000 killed during 1973 drought
25% of all cattle were killed or slaughtered.
1991 4 million people facing starvation - reliant on food aid.

Question 22

Human causes of drought in Australia.

Answer 22

Over extraction of Murray-Darling river - supplies 75% of water but only covers 14% of land.
Highly developed country with water intensive technology, consumes 340 litres of water per person per day, population grows by 1.4% per year.

Question 23

Physical causes of drought in Australia

Answer 23

El Nino- 2016 worst drought in 125 years.
Recieves 455mm of rain per year.
Worlds driest continent, 7 degree increase in temp and 40% decrease in rainfall is expected by 2070.

Question 24

What are Australias drought prevention techniques?

Are they successful?

Answer 24

Restiction on agriculture water usage only knocked 1% of Australia’s economy in 2006-7
Use Grey water - recycled domestic water e.g from washing machines- for agricultural usage.
For stage drought plan- starting with only being able to water lawns for two hours a day to banning car washing and outdoor sprinklers/ hosepipe.
Refusal to sign Kyoto Protocol - failure to mitigate climate change which may exaggerate drought and ENSO cycles.

Question 25

Impacts of drought in Brazil

Answer 25

Reduced crop of Arabica coffee beans pushed global prices up by 50%.
Water rationing for 4 million people
Water supply cut off for 3 days per week in poorest areas.
Braxzils largest reservoirs- largely decreased in capacity - some at only 1%.

Question 26

Causes of drought in Brazil

Answer 26

Sao Paulo - industry and farming caused groundwater supplies to deplete.
Made worse as the country starts to develop and industrialise.

Question 27

Human environmental impact of water-based ecosystems

Answer 27

Globally between 100,000 and 200,000 aquatic wildlife are at risk of extinction because of human degradation to rivers.
Europeans have removed over 90% of floodplains and wetlands as they have urbanised.

Question 28

What are wetlands and why are they important?

Answer 28

Areas of marsh or static water, where water covers the soil all year.
Found in every continent except Antarctica.
Important for wildlife: high biodiversity, 90% of shellfish is farmed here.
Slowly release water by filtration in groundwater supplies after removing harmful chemicals, recharging safe groundwater supplies.
Act as flood control and natural buffers from marine erosion.

Question 29

What are the impacts of destruction/drought of wetlands?

Answer 29

Loss of biodiversity and holes in foodchains, ducks and thrush.
Release ancient carbon stores.
As water volume decreases the concentration of pollutants increases.
Everglades Floride is now half it’s original size.

Question 30

Impact of drought in Brazil

Answer 30

Reduced crop of Arabica coffee beans pushes global prices up by 50%
Threatens Brazil’s dependency on Hep which supplies 70% of Brazil’s electricity.
Water rationing for 4 million people

Question 31

Cloud Seeding Idaho USA

Answer 31

Cloud seeding uses silver iodide to increase rates of precipitation.
Since 2017 has been used to increase the snow pack, which then melts in summer helping farmers reach irrigation demand.

Question 32

Flood management UK Pickering

Answer 32

Planted 40,000 trees and restored soil embankments.
Reduced peak river discharge by 20%.
Increased rates of infiltration and interception.

Question 33

Urbanisation Houston - flood risk

Answer 33

Population has doubled.
Built 7,000 homes on floodplain.
Lost 100,000ha of wetlands
Caused substantial flooding during Huricane Harvey in 2017.

Question 34

Causes of flooding (basic)

Answer 34

Climatological - rain, snow melt, ice melt.
Part climatological - coastal storm surges (links to coasts topic)
Other - tsunamis, failures of dams, landslides.

Question 35

What are the different types of flooding?

Answer 35

Groundwater flooding - mainly in low lying floodplains and estuaries, ground becomes saturated from prolonged, heavy rainfall.
Surface water flooding - mainly in urban areas, due to impermeable geology rainfall can’t infiltrate so flows over land.
Flash flooding - small basins, associated with short lag times and intense rainfall, impermeable, unvegetated and steep land.

Question 36

How does the Indian Ocean Monsoon form?

Answer 36

Warming northern hemisphere, hotter atmosphere temperatures over the Indian Ocean.
Warmer ocean waters are still lower than the heated land.
Temperature difference causes air above land to rise faster, this creates strong winds which are dragged in from above the oceans.
This brings low pressure conditions with large amounts of stored water vapour over land causing intense rainfall.
80% of India’s rainfall occurs during monsoon season.

Question 37

The ITCZ and monsoons.

Answer 37

The movement of the ITCZ represents the movement of the wettest conditions.
When the ITCZ moves northwards in June and September, monsoons are experienced in West Africa and India.
When the ITCZ moves south in December to January Brazil, Australia and southern Africa experience monsoons.

Question 38

India Summer v Winter Monsoon

Answer 38

Summer monsoon is a wind system that blows in from across the Indian Ocean, brings intense rainfall and powerful storms. Often causes flooding.
Winter monsoon is a wind system that blows from the northeast across the Himalayas towards the sea from October through February. Carriers very little moisture and can result in drought if it fails to return normal moisture levels.
Together they create wet and dry seasons.

Question 39

Human causes of flooding in Pakistan.

Answer 39

Urbanisation - rapid growth of Karachi Mega-city, increased impermeable surfaces and vulnerability to flooding.
Lack of governance- in 2010-2011 floods the government failed to warn rural communities and monitoring technology failed in older facilities, lack of preparation.
70% of the population works in agriculture

Question 40

Physical Causes of Flooding in Bangladesh.

Answer 40

75% of annular rainfall occurs during the June-September monsoon season, this also combines with snow melt from the Himalayas increasing river discharge.
Majority of land is only 1m above sea-level, very vulnerable to sea-level rise from thermal expansion and storm surges.
Global hotspot for storm surges, funneled due to triangular coast shape to Bay of Bengal, 2007 Hurricane Sidr 3 million people were affected.
80% of land is considered flood plains

Question 41

Human causes of flooding in Bangladesh.

Answer 41

70% of land is dedicated to growing crops, deforestation, land degradation, compacts, reduces infiltration.

Question 42

Bangladesh, India, Nepal flooding conflict.

Answer 42

Nepal has a deforestation rate of 1.7%, India blame Nepal deforestation for increased flooding along their border.
Failure of the two governments to communicate means flood warnings are not passed between countries increasing vulnerability - 2013 flood in northwest India called the Himalayan tsunami killed 6,000 people, India believe Nepal new of the event before them and failed to warn them.
Nepal blaims increased India infrastructure including two dams to obstructing the natural flow of water.

Question 43

Mississippi 1993 floods

Answer 43

Over 10,000 square miles were flooded
Leaves along the upper mississippi river forced water to flow downstream faster and stronger, affecting the downstream towns.
2/3 of leaves flooded
50 killed
Over $10 billion in damages.

Question 44

Impacts of 2010 flood in Pakistan

Answer 44

3.6 million ha of arable crops were destroyed.
Costing the agriculture section £1 billion
UN launches an appeal for £290 million in emergency relief aid.
20 million people were affected and 1,600 killed.
11,000 schools were closed

Question 45

Causes of flooding in the UK (physical)

Answer 45

Mainly occurs in the NW due to geographic rainfall.
Low pressure system depressions are more common in winter.
Progressive cycles is the term for when there is the most contact between the Feral and Polar cell causing stronger low pressure conditions such as high intensity rainfall.

Question 46

What is frontal rainfall?

Answer 46

Boundary between cold polar air and warmer tropic air
Warm air is pushed as a wedge into cold.
Warm air front advances followed by cold air.
Warmer air holds more water vapour.
Warm air is forced upwards over cold air causing low pressure rainfall often warm thunderstorms.

Question 47

What are some general environmental impacts of flooding?

Answer 47

Recharged groundwater sources positive
Increased connectivity between aquatic habitats (positive)
Soil replenishment (positive)
Flooding can trigger breeding an migration of species (positive)
Floodwater can carry pollutants into rivers and lakes, cause eutrophication or decrease water quality killing aquatic species (negative)

Question 48

UK human causes of flooding.

Answer 48

Building of houses on floodplains has increased by an area of 1.2% per year since 2011.
Urbanisation - 83% live in urban areas.
Removal of forest habitats, UK is one of Europes least wooded areas,
In 2020 the UK lost 4.15kha of natural forests.

Question 49

Physical causes of Storm Desmond

Answer 49

Cumbria recieved more than one months rain in 24 hours, saturated land decreased infiltration more surface runoff.
Honnister received 341 mm of rain between the 4 and 5 of December.

Question 50

What are the impacts of Storm Desmond?

Answer 50

over 5,200 homes were flooded and many more (a businesses) were left without electricity.
40 schools closed.
Mainline rail route to Scotland was closed due to flooding
2 deaths
Government gave £50 million to local councils to help people ensures their homes were safe.

Question 51

Impacts of Storm Eva

Answer 51

9000 homes were flooded and 7,600 were left with no electricity.
The average cost of a domestic property floodclaim was £50,000 pound.

Question 52

UK government response to Storm Desmond, Eva and Frank

Answer 52

committed £2.3 billion for flood management projects over the next six years.

Question 53

El Nino flooding

Answer 53

Vast areas in Paraguay, Argentina, Uruguay and Brazil are being hit by the worst flooding in 50 years, forcing the evacuation of more than 150,000 people.

Question 54

2012 York Flooding

Answer 54

2012 York floodgate 4 out of 8 pumps overheated, making the floodgate fail leaving 3,500 homes vulnerable.

Question 55

Flood Impact Bangladesh 2004

Answer 55

100,000 people suffered diarrhoea from floodwater.
600 deaths and 3 million people were homeless
2.2 million acres of damaged cropland.

Question 56

Impact of climate change of precipitation

Answer 56

A warmer atmosphere has a greater water holding capacity.
Change the type of precipitation - more rainfall rather than snow in northern regions.
Rainfall intensity is expected to increase in the tropics and high latitudes.
Rainfall is expected to decrease between 10 and 30 degrees latitude.

Question 57

Impact of climate change on soil moisture.

Answer 57

Uncertain expected to increase in line with precipitation rates.

Question 58

Impact of climate change on oceans.

Answer 58

Sea-level rise due to thermal expansion and melting glaciers.
Ocean warming will encourage evaporation and cyclone formation.

Question 59

Why are we uncertain about climate changes affect of future water sources?

Answer 59

Climate models vary, uncertain if global temperature rise will remain at 1.5 degrees.
The impact of tipping points and feedback loops is not yet known.
Development of new technology may allow new water sources to be accessed.

Question 60

Climate change impact on the hydrological cycle in the UK?

Answer 60

By 2100 flood risk will increase by x4.5 and drought risk will increase by x3.

Question 61

How has climate change benefited the Sahel?

Answer 61

1984-5 drought made famous by Band Aid, 1 million died as a result of famine.
1950 and 1980s rainfall fell by 40%
New patterns of climate has started to appear, with my more wet periods in between droughts. Uncertain if this is is a flucation or will be a reoccurring pattern.
This has allowed for re-greening, planting trees and bushes as part of a sustainable land management scheme.

Question 62

How has climate change negatively affected Californians hydrological cycle?

Answer 62

2014 Sierra Nevada region faced three times the normal number of wildfires due to dry ground.
Groundwater levels fell by 30m between 2011 and 2015.
2015 Snowpack levels were at a record low, snowpack provides 1/3 of Californias water supply in summer.