water case studies

Question 1

How have humans disrupted the Amazonia drainage basin

Answer 1

• deforestation - destroys natural habitat of countless species and contributed to climate change
• industrial development - mining and oil drilling - lead to water pollution , soil erosion , destruction of animal and plant life
  contructtion of infrastructure can disrupt flow of water and nutrients
  Climate change - lead to more frequent wildfires and changing rainfall patterns

Question 2

what have been the impacts of human disruption to the amazon drainage basin

Answer 2

• loss of millions of hectares of forests - loss of habitat leading to exctintion of many species and dirsuption of ecosystems
• amazon forest is becoming drier and more vulnerable to fire
• less rainfall leading to possible droughts and floods
• water pollution
• loss of biodiversity
• threats to indigenous communities who rely on the rainforest for their livelihoods and cultural tradition

Question 3

what does the water budget in a tropical climate look like

Answer 3

• characterised by high levels of precipitation and EVT
• due to warmer temps higher humidity aswell as presence of rainforests and other vegetation that help to generate and retain moisture

Question 4

why is EVT high in tropical climates

Answer 4

warm temps and high humidity create ideal conditions for plant growth and water reuptake - as a result precipitation is quickly taken up by plants and returned to the atmosphere through transpiration

Question 5

how can the water budget in tropical climates be innfluenced

Answer 5

• soil type , topography and human activity
• deforestation can reduce EVT and increase runoff - lead to changes in local water cycle anf affect downstream resources
• land use changes - agriculture and industry can lead to pollution and overuse of water resources

Question 6

what does the water budget in a polar climate look like

Answer 6

• dominated by freezing and melting of sea ice
• due to low temps and limited precip amount of water available is very low
• so water budget largely determined by exchange of water between the atmosphere ocean and cryosphere

Question 7

what does precipitation , evaporation and runoff look like in a polar water budget

Answer 7

precipitation- relatively low - mostly falls as snow
evaporation- low due to cold temps and low humidity
runoof- limited - can occur as either liquid water or as meltwater from glaciers and sea ice
change in water storage is largely determined by the melting and freezing of sea ice and glaciers

Question 8

what impacts are there on a polar water budget

Answer 8

changes in temp and precip patterns can have significant impacts and can contribute to changes in sea level and ocean circulation patterns

Question 9

what are the differences between the Yukon river regime and the Amazon river regime

Answer 9

Amazon -
- has a wet season (december to june) where rainfall and snow melt from the andes causes a large increase in river flow
- has a dry season (july to nov) where the flow rate decreases due to reduced rainfall and increased evaporation

Yukon
- seasonal melt of snow and ice
- highest water levels during spring and summer - highest in late june early july

Question 10

what are the reasons for the differences between the Yukon and the Amazon river regimes

Answer 10

climate -
- amazon - has a tropical monsoon climate - receives large amount of rainfall
- yukon - subartic climate - much lower annual precip mostly in form of snow

Geology -
amazon - dominated by sedimentary rocks - porous and allow for rapid infiltration and runoff
- has extensive wetlands and floodplains that store water and regulate discharge
- Yukon- crystalline rocks - relatively impermeable and store water in glaciers and snowpacks
- has extensive perma frost - limits infiltration rates and contributes to t surface runoff during spring and summer

Soils -
- amazon - has soils that have low water holding capacity and limited permeability which can lead to rapid runoff - has wetlands and floodplains to help counter act that
- Yukon - has soils with high water holding capacity - soils store water as snow and ice during winter and release during spring and summer - permafrost limits the infiltration into the soil so surface runoff during winter

Question 11

what are some facts ( a few ) about the droughts in Australia

Answer 11

30% of the country usually affected in any one year
the big dry of 2006 covered large areas of australia for several years
the big dry was assessed as a 1 in 1000 year event

Question 12

what are some physical reasons for drought in Australia

Answer 12

• low highly variable rainfall because of the sub tropic high pressure belt
• most closely linked to el nino events
• since the 1970s there has been a shift in rainfall patterns in the eastern area where most people live
• the big dry was thought to be associated with longer term climate change leading to a trend of a warmer drier climate for south eastern Australia

Question 13

what are the impacts of the droughts in Australia

Answer 13

• the big dry affected more than half the farmlands especially in the murray darling basin which provides 50% of the nations agricultural outputs - impacts on wool and food supplies , wheat and meat exports
• farmers also relied on water for irrigation of rice cotton and fruit farms
• reservoirs fell to 40% of their capacity
• bushfires more common - people and animals lost property and lives
• rivers dried up and loss of fish populations

Question 14

what were some human impacts that makes the sahelian region prone to drought

Answer 14

• air pollution from europe and north america cooled the earth , preventing tropical rains moving northwards
• higher sea temps from global warming prevented moist atlantic air moving over western sahel
• desertification has resulted from overuse of land due to population pressures

Question 15

What happened during the UK flood events from 2015-2016

Answer 15

• during the winter of 2015-16 northern parts of the uk were affected by a sequence of depressions (low pressure systems) , each providing periods of prolonged intense heavy rainfall

Question 16

what were some examples of the different flood events in the UK 2015-16

Answer 16

Storm abigail in november saturated soils
- storm desmond in december caused flooding in cumbria with over a months rainfall in one day (convectional, orographic and frontal)
- storm eva caused flooding over the pennines
- storm frank in western areas

Question 17

what were some socio- economic impacts of the uk 2015-16 flood events

Answer 17

• over 16,000 properties over the uk were flooded
• uk government provided 200 million for flood recovery
• estimated total economic costs at 5 billion
• consumers and deliveries unable to reach businesses
• people evacuated
• deaths
• sediment deposited in houses
• schools closed
• roads and railways blocked

Question 18

what were some environmental impacts from the UK flood events in 2015-16

Answer 18

• erosion of rivers and coastal areas
• soil degradation and erosion in agricultural areas
• loss of habitats
• ## flood waters picked up pollutants such as chemicals and sewage pose a risk to environment and human health

Question 19

what is an example of a place facing climate variability and increasing risk of water insecurity

Answer 19

the UK - having wetter winters but drier summers
- influenced by the North Atlantic Ocean, which circulates warm water from the tropics towards the Arctic and cold water back towards the equator
- also influenced by atmospheric circulation patterns, such as the North Atlantic Oscillation (NAO), which is a natural cycle that affects the strength and position of the jet stream.

Question 20

what is an example of a place facing salt water encroachment and at an increased risk of water insecurity

Answer 20

The mekong delta in vietnam
- sea level rise is pushing salt water higher upstream and infiltrating freshwater aquifers
- reduced sediment deposition from building dams upstream - delta has less sediment and is sinking so at risk further from encroachment
- over abstraction in aquifers

Question 21

what is an example of a place where there has been over-abstraction of groundwater

Answer 21

Mexico city
- there has been an increase in groundwater abstraction due to an increase in population - led to ground subsidence
- over abstraction causes the water table to drop and the rock and sediment above the table to compress - causes surface land to sink
- mexico also built on an old lake bed - soft sediment more prone to compaction

Question 22

what have been the impacts of land subsidence in mexico city

Answer 22

• led to damage to infrastructure e.g. in the 1970s a railways station had to be closed due to severe subsidence
• Land subsidence has reduced the capacity of drainage systems in Mexico City, leading to more frequent and severe flooding.
• rate of land subsidence in Mexico City has led to the loss of up to one meter of groundwater storage capacity per year
• the loss of wetlands, sinking of forested areas, and changes to river flow patterns.
  -subsidence has caused damage to historic buildings and cultural heritage sites, posing a threat to Mexico City’s cultural identity.

Question 23

what is an example of an area experiencing contamination from farming / industry

Answer 23

Animas river in colorado
- flows through the San Juan Mountains, an area with a long history of mining. Over time, mine waste has built up in the mountains, and when water comes into contact with the waste, it can become contaminated with heavy metals such as lead, cadmium, and arsenic.
- an environmental disaster occurred when a mine near Silverton, Colorado, released millions of gallons of wastewater into the Animas River
The contaminants were harmful to aquatic and human life , especially if they managed to get into water sources

Question 24

why is there conflict at the Nile delta about usage

Answer 24

11 users
- vital source for Egypt and sudan
- ethiopia (upstream from these two) are building large hydroelectric dam (GERD)
Egypt concerned about the dam and how it might reduce flow downstream - this could impact agricultural production, food security and economy
- sudan have same concerns
- also environmental concerns - damage to ecosystems
- treaties have been signed but still conflict over water allocation and management of the basin as a whole

Question 25

what is the south - north water transfer scheme in china

Answer 25

• north east china water scarce due to large cities such as beijing and overuse by farming and pollution
• most of chinas water in south
• devised worlds largest water transfer scheme - 25bn metres cubed of water a year is to be transferred from the yangtze river basin over 1000km to the north

Question 26

what are some downsides to the south- north water transfer scheme in china

Answer 26

• very expensive
• water may be too expensive for farmers
• 300,000 people displaced
• doesnt tackle overuse or pollution of water
• water scarcity in south may be created

Question 27

what are some benefits to the south- north water transfer scheme in china

Answer 27

• improved water supply in the north
• increased agricultural production - increased food security and economic growth in north
• creating jobs
• project includes measures to improve water quality in rivers and lakes in northern china

Question 28

how has singapore used sustainable management to conserve water

Answer 28

• recycling water in their NEwater scheme, where grey water is purified through membranes and ultraviolet disinfection (in future will provide 55% of the countrys needs) - used for non potable uses such as irrigation and air conditioning
• has 4 desalination plants that can produce up to 100 million gallons of water a day
• rainwater harvesting for things such as flushing toilets
• water management schemes where people and businesses encouraged to use water efficiently - enforced by regulations and fines

Question 29

what are some challenges for managing the colorado river in an integrated way

Answer 29

• large size of basin and long length of river
• large water demand and growing population
• large part of the basin is desert or semi arid
• seven US states and Mexico take water from the colorado
• climate change is creating drier conditions and variable river levels

Question 30

why has there been a need for a new agreement about the colorado river since 1990

Answer 30

-there were agreements dated back to 1922 that shared out water based on usage
- states lower in the basin used all their share of water for the first time
- environmental regulations increased complexity

Question 31

what has happened in recent years in regards to the colorado integrated drainage basin management

Answer 31

• not been enough water to supply demand leading to disputes and no agreement
• states have started making alternative plans as much as they can e.g. arizona recharging their aquifer in high discharge years

Question 32

where is the aral sea

Answer 32

located on border between Kazakhstan and Uzbekistan

Question 33

what is happening at the aral sea

Answer 33

• Steadily shrinking since the 1960s used to be the 4th largest inland sea
• By 2007 had declined to 10% of original size and split
• Its level had fallen by up to 40m

Question 34

what are the physical causes of the aral sea shrinking

Answer 34

Rainfall only 100-300 mm annually (fallen recently) and is unevenly distributed
80% of country has flat desert terrain
Landlocked countries around it - sea cannot regulate temp or rainfall; winter temps often below -20c and summer temps exceed 40c

Question 35

what are some human causes for the aral sea shrinking

Answer 35

Soviet government directed rivers to use water for agriculture irrigation in 1990s but systems are poor quality and have poor drainage system
Today Uzbekistan government have set up irrigation schemes to allow the country to remain one of the worlds largest cotton exporters

Question 36

what are some social impacts of the aral sea sinking

Answer 36

local residents suffer from health issues caused by windblown dust and salt from the sea bed
People may no longer be able to feed themselves as land has become so infertile- 10 mil maybe forced to migrate
Increased salination- mineral content went from 10g/l to 40g/l
60,000 abandoned livelihoods in fishing

Question 37

what are some economic impacts of the aral sea shrinking

Answer 37

Unemployment and economic hardship

Question 38

what are some environmental impacts of the aral sea sinking

Answer 38

desertification - by 1990 95% of wetlands and marshes had become desert
Amount of dust blown by Aral Sea has increased global particulate levels by 5% - global warming