WATER CYCLE! Flashcards
how much of the earth’s entire water supply is found in the oceans and seas?
96.5%
types of local water stores:
soil moisture interception groundwater surface storage vegetation storage
where is the earth’s surface water found?
ground ice and permafrost lakes and rivers soil moisture swamps and marshes the atmosphere the biosphere
what are flows?
how water moves from one store to another in the global hydrological cycle eg. through flow or channel flow
human factors affecting drainage basins:
over abstraction
urbanisation
reservoirs
deforestation
what does high vegetation cover increase in a drainage basin?
evapotranspiration
the outputs from drainage basins:
channel flow
evaporation
transpiration
what do we call it when the volume of groundwater being removed is greater than the volume being replenished?
over abstraction
what is direct run off?
the drainage basin flows that happen when water flows across the ground’s surface
physical factors influencing drainage basin cycle:
soil type rock type vegetation cover relief of the land climate
what is fossil water?
untouched ancient freshwater stores
what is another word for the polar areas of the world?
cryosphere
only 2.5% of the earth’s water is:
freshwater
how much of the precipitation that a rainforest receives is returned to the atmosphere via evapotranspiration?
50%
tropical hydrology facts:
the high density of vegetation consumes the majority of precipitation
50% of the precipitation is returned via evapotranspiration
rainforests are able to generate their own water cycle due to conventional rainfall
what is released into the atmosphere as ice and permafrost thaw?
biogenic gases
why are human influences on the Yukon River minimal?
it is a largely natural area
what happens to the Yukon River in summer?
snowmelt increases discharge
what process happens due to the high temperatures and high levels of biodiversity found in the Amazon rainforest?
evapotranspiration
what types of landscapes do the Yukon River flow through?
mountains and tundra
what is river discharge?
the volume of water flowing in a river every second and is measured in cumecs (m3/s)
what is river discharge measured in?
cubic metres per second
how does impermeable rock and soil reduce the lag time and increase peak discharge of a river?
precipitation will not be able to infiltrate into the ground, increasing surface runoff
examples of effects of humans on hydrographs:
urbanisation leads to an increase in impermeable surfaces e.g. tarmac + concrete
dams + reservoirs regulate flow of rivers
abstraction of aquifers lowers groundwater levels
ploughing of agricultural land increases surface runoff
what can be used to regulate the flow of a river by storing water before choosing when to release it downstream?
reservoirs
what physical factors affect storm hydrographs?
size and shape of catchment area
drainage density
rock and soil type
relief and vegetation
how do La Nina cycles lead to flood risk in Australasia?
because low pressure systems lead to warm rising air that produce clouds and rainfall
which group of people were worst affected by the Brazilian drought crisis in 2014?
poor and rural communities
what consequences are true during El Nino?
Australasia is at increased risk of drought
happens over South Pacific Ocean
Australasia has cooler than normal ocean temps
warm water moves to South American coastline
why did Brazilian residences drill wells illegally in 2014-15?
they could not afford the government charge
what wetland species of bird in Minsmere, Suffolk is impacted by the dry soil surface present during a drought?
Snipe and Thrush
what factors can turn a small fire into a wildfire?
lightening storms and high winds
how can a reduction in canopy cover in rainforests lead to drought?
it leads to less interception and inflitration, also decreases evapotranspiration which means water vapour and rainfall reduces
how does the removal of vegetation contribute to the causes of flooding?
it increases surface runoff
impacts of snowmelt:
increased surface runoff
consequential flash floods
what are the characteristics of flash flooding?
no warning and happens quickly
effects of flooding on soils:
sediment from banks and beds of rivers erodes
sediment can block sections of a river
erodes fertile soil in places like Amazon
2015 Cumbria floods statements:
42,000 homes without power
5000 homes flooded after 3 days
damages to homes were £150 million
how can flooding have a devastating impact on ecosystems?
if plants, agriculture or habitats are damaged by flooding, the animals that are dependent on them for food and shelter are at risk
animals have to compete for limited resources/ migrate to other ecosystems leading to a decline in some species
how does climate change impact the hydrological cycle inputs and outputs?
some areas see a decrease in temperature that reduces evaporation rates
if temperatures decrease to below freezing, water may remain frozen and be stored as ice
what are potential effects of climate change on stores and flows?
sea ice not forming to the same extent
permafrost loss
Lake Chad drying up
what are the effects of climate change changing weather patterns?
it changes precipitation and evaporation which can impact a region’s hydrological cycle and ecosystems
what year saw the smallest amount of winter Arctic ice since the 1960s?
2018
what are the impacts of climate change?
likelihood of tropical storms increase
sea levels rise
sea surface temps increase
higher levels of rainfall = higher precipitation rates and flood risk in tropical regions near coastline
what area is at increased flood risk during El Nino?
South America
how much of the Sahel’s precipitation falls in the rainy season from July to September?
90%
what has the recent increase in wetter years in the Sahel been referred to as?
a re-greening opportunity
the use of water-consuming devices increases as countries develop, the middle classes expand and what increases?
living standards
what does water stress mean?
when a water supply is limited within an area, it can be seen to have water stress
can be seen where the demand is significantly above that of the available clean water supply
why is Greenland at low risk from water scarcity?
melted ice-sheet can produce freshwater
low air pressure systems area:
warm moist air rises –> warm air cools and condenses to form clouds –> precipitation e.g. Brazil
high air pressure systems area:
air sinks –> no clouds form –> no precipitation e.g. Morocco
what country is the biggest consumer of water per capita in the world?
USA
why are India and China at a high risk of water stress?
these countries have the fastest growing populations and an increase in middle classes using water consuming devices
physical components of water stress statements:
Brazil has relative water security due to their high rainfall
the Hadley and Ferrel cell meet causing an area of high pressure
countries near the equator see more rainfall and less water stress
climate change will melt Greenland’s ice-sheet to produce freshwater
why is there a water management problem in rural Tanzania?
farmers pay a one-off annual fee to access a water source (river or well) which leads to farmers using more water than necessary because they feel like they have already ‘paid for it’
what are human factors affecting water stress?
fast-growing populations
high living standards
industry demands
what is saltwater encroachment?
where groundwater near the coast is contaminated with sea water (salinisation) e.g. Tuvalu
what can increase the risk of saltwater intrusion to freshwater?
sea level rise, coastal erosion and local abstraction
human causes of water insecurity:
agricultural water contamination (agriculture)
industrial water pollution (industrialisation)
rivers and aquifers over-abstraction
population growth
increasing living standards
fertilisers and pesticides are examples of what?
agricultural waste products
physical causes of water insecurity:
climate variability
saltwater encroachment
over-abstraction of aquifers
what is the single largest user of water?
agriculture: 70% of the world’s water, 90% in developing countries
water resource privatisation means that people have to what?
pay more
what does the Water Poverty Index determine?
the quality, quantity and accessibility of water
why are energy demands increasing globally?
as electricity access increases and standards of living improve = demands more energy
when was the Water Poverty Index developed?
2002
what is the volume of water being used in agriculture?
not sustainable
which country has had complete anonymity over developments on the Nile since 1929?
Egypt
concerns about water conflict in Ethiopia:
ethnic groups are threatened by poor crop yield
tribal conflict is a concern because of the minimal water supplies
potential devastation to Lake Turkana
Lake Turkana’s water levels could drop 10m
what do those in favour of the Gilgel Gibe III Dam say about artificial floods?
that they could continue to support the indigenous population
establishing large plantations of cotton and sugar cane could economically benefit those populations
200,000 people downstream of the Gilgel Gibe III Dam rely on the seasonal floodwaters to replenish the dry soils for what?
subsistence farming
what is one of the hard scale engineering schemes that attempt to fix water disparity in China?
North-South Water Transfer Project
what happened to 1.3mil Chinese residents as a result of the Three Gorges Dam?
they were relocated
one positive and one negative of the Israel desalination plants:
:) can produce up to 600tonnes of clean drinking water in an hour
:( each plant requires its own power station
what are the pros of the Three Gorges Dam?
controls flooding on the River Yangtze
improve the supply of water by regulating the flow
provides HEP energy
makes the river navigable: important for economic development
desalination plants provide a supply of water that is what?
reliable
crops produced with smart irrigation produce the same quality and quantity whilst using what?
less water
what is smart irrigation?
a sustainable water management scheme that provides crops with below the optimum water levels during the growth stage, so they become less sensitive to the lack of water
why has Singapore introduced the recycling of water?
it suffers from water scarcity
high temps in Singapore mean evaporation rates are high and there is a lack of groundwater resources despite the high levels of rainfall
NEWater plants are currently meeting how much of Singapore’s water needs?
30%
how do local people in Kenya extract the trapped water from behind sand dams?
piping the water through the dam to a tap
digging wells
digging holes
how much has the use of smart irrigation for fruit trees increased water productivity by in Australia?
60%
sustainable water management techniques in Singapore:
rainwater collection and treatment
NEWater plants
an agreement to import water from Malaysia until 2061
desalination plants
in what Kenyan district have local people started building sand dams to increase the sustainability of their water supply?
Machakos District
the Colorado River facts:
starts in the Rocky Mountains
flows through semi-arid areas towards Gulf of California in Mexico
233km long
97% flows through USA
the Helsinki Water Convention facts:
the Integrated Water Resource Management approach was established as a result
Convention entered into force in 1996
held by UNECE
held in 1992
what type of approach is the IWRM?
holistic
what do the Berlin Rules state?
how freshwater resources should be shared, whether nationally or internationally
adopts nine water management principles
what has climate change resulted in for the Colorado River?
lower precipitation in the Colorado River basin = increased frequency of drought = further pressure onto water source
when did the International Law Association approve the Berlin Rules on Water Resources?
2004
