Water Cycle Flashcards
what is a drought
water deficit in a particular place over a period of time compared to the average rainfall
types of droughts - meteorological
the degree of dryness compared to normal precipitation
types of droughts - agricultureal
insufficient water for crops so that they will wilt without irrigation
types of droughts - hydrological
where drainage basins suffer shortfalls
why is the rainfall in brazil predictable, explain the reason
moist air moves in west - south Atlantic across the amazon basin.
moist air encounters high andes mountain range to flow west of continent, forced to turn southwards - maintaining flow of mixture
what happened in 2014-2015 in Brazil
high pressure system diverted rain-bearing winds further north further away from Amazon, also prevented them going south
where did the heavy rains occur and not occur
Bolivia and Panama heavy rains, Brazil no heavy rain
impacts of Brazil drought
water rationing for 4 million people - water supplies cutoff for 3 days in towns
halting of HEP production - led to power cuts
increased groundwater abstraction - which led aquifers to became dangerously low
reduced crop arabica coffee beans (Brazil world largest producer.
tipping point
system changes from one state to another
resilience
ability of a system to bounce back and survive
impacts of droughts on the amazon
amazon rainforest capacity to absorb carbon will decline
regional water cycles will change and soil temperatures will increase
- amazon rainforest replaced with Savannah - grasslands
- world lose major carbon sink and source of mixture
impacts of droughts on rainforest ecosystem
prolonged drought causes forest stress and sets up chain reaction
younger trees die - reduces canopy cover - this reduces humdiity
water vapour decreases and therefore rainfall decreases
impacts of drought on wetland
drought increased tree mortality - reduces habitats for wild animals - as well as cattle ranching and ecotourism
wildfires became major threat - caused by cattle ranchers setting fire to grass left by the cattle (which their normally do), however during drought - fires spread out of control
key concepts - casualty
varying cause of flooding
key concepts - systems
how weather systems are linked to causes flooding
key concepts - resilience
ability to places to respond to floods and their impacts
other causes of flooding - monsoon
monsoon rainfall - occurs south and Southeast Asia in may July September. leads to landslides and evacuations in village in the Philippines 2016
other causes of flooding - snowmelt
snow melts and resulting water cannot infiltrate the soil or ground surface
river restoration - what happaned Kissimee
Sever flooding on river 1940s meant the river was channelized to stop and ease navigation
1962-1971 river replaced by 90km
water entering basin controlled by storage lakes
impacts of river Kissimmee restoration
less recharge in miamis groundwater aquifers
-92% in bird
less water flow - from 0.42m per second to 0.05
salinisation of water supplies
river restoration - what happened
1975 Kissimmee river saying work started in 1999 -2012
11000 hectares restored
levees removed meanders restored
parts of canal remain to protect settlement
what is desalination
removal of excess salt and other minerals from water. produces fresh water suitable for human consumption and irrigation
causes of meterlogical drought
complex interactions between oceans, atmosphere, biosphere, crysophere and land which produces the climate of the globe
normal conditons in the pacfic ocean - ENSO
trade winds blow from east to west along the equator
air pushes warm water west
thermocline upwelling
rain clouds forms by warm, moist air rising cools and condenses
hot and wet in Australia
cold and dry in South America
conditions during el nino
air circulation is reversed
trade wind pattern is disrupted may even slacken which can affect the ocean currents
south coast of america is worm
when does el nino happen
every 3-7 years
el nino around the world
warm water replaces the cool water around Peru
cooler water then replaces the warm water at Austrailia and Indonesia
what conditions to el nino trigger with example
dry conditoons around the world
Monsoon rain in India and South East Asia fail
when may La Nina event happen
sometimes after an el nino event
explain La Nina
the build up of cooler than usual sub surface water in the tropical part of the Pacific
more extreme than normal
conditions of La Nina event
severe drought conditions, western coast of South America
hot and wet in Australia
cold and dry South America
effects of La Nina
strong air circulation
warm water moving east to west
causes of natarual desertification
rainfall patterns change, rainfall becoming less reliablem seasonally and annualy, droughts get common
vegetations gets stressed and dies leaving soil
soil eroded by wind and occasional intense shower
when rain falls it is rare and short, making it hard for the soil to recapture the rain and store it
what is desertification
process by which once productive land gradualluy changes to desert like landscape
where could desertfication take place
semi arid landscape on edges of existing deserts
how human enhance the impacts of droughts
deforestation
trees cut down for fuel, fencing and housing, roots no lonher bind soil and erosion occurs
how human enhance the impacts of droughts
population
rapid population growth puts pressure on food supplies, migrants moving from one disaster help create another one
how human enhance the impacts of droughts
overgrazing
too many goats, cows, and sheep and cattle destroy the vegetation cover
Northern Sahel region stats
30%-40% annual depature from normal rainfall
Droughts in Austrialia
30% affected by serious rainfall deficiency
how have Australia not followed the Sahel region in being desertification
careful management of scare water, sorting out the competing demands or irrigation and urban dwellers
large scale recyclign grey water
constructing desalination plants
what important functions do wetlands perfrom
temporary water storage
recharging of water aquifiers
trapping pollutants
providing nursureies for fish and feeding sities for birds
wetlands and the earth
cover 10% earths land surface
what is challanging wetlands survival
droughts pose a threat, main threat is artficial damage
what are forests responsible for
interception, which means reduced infiltration and overland flow
what is threatening forest
droughts, but mainly humans with deforestation
what is droughts causing for forests
physiological damage
increasing the susceptibility of pines and firs to fungal diseases.
tree mortality on the rise
drought and tropical rainforest
increased mortaliity due to droughts and appears to have a greater impact on larger trees
causes of meteological flooding
prolonged periods of heavy rain - asain monsoon and deep depressions across UK
intense storms lead to flash flooding common in mountanious areas
rapid snowmelt during warm springs - Siberia plains
why is Bangledesh common to floods
land of floodplains and deltas built up by Ganges, Padma and Meghna
what is tidal flooding a result of
storm surges or when high river flows meet meet high spring tides in estuaries
what is a storm surge
low pressure which rasies height of the high tide at the sea strong onshore winds drive the high tide to the coast, breaking coastal defences and flooding areas
The likelikhood of flooding is also increased by other physical circumstances:
where volcanic activity generates meltwater beneath ice sheets that is suddenly released (jökulhlaups)
when ice dams suddenly melt and the waters in glacial lakes are release
where earthquakes cause the failure of dams or landslides that block rivers
what has combination of economic and population growth meant
floodplains built upon natural landscapes to be modified for agriculture, industrial and urban purpose
Urbanisation and Flood risk
Woodlands intercept rain and transpire moisture; roots give good soil structure. Deforestation destroys this.
Dams built to supply towns with water
Sewers feed water into channel
river mismanagement - Dams
block the flow of sediment down a river, so the reservoir gradually fills up with silt; downstream there is increased river bed erosion
river mismanagement - embankments
designed to protect from floods of a given magnitude. can fail when a flood exceeds their capacity when this happens, the scale of flooding is that much greater.
river mismanagement - channelisation
effective way of improving river discharge and reducing the flood risk. however it displaces the river downstream. other locations may well be overwhelmed by the increased discharge
soft engnerring examples for lower flood risk
making use of floodplains - for storing water and using them for natural conservation , agriculture and recreation
socioeconomic impacts of flooding
death
injuries
trauma
water borne diseases spread
destruction of crops and loss of supplies
interuoption to water and energy supplies
enviromental impacts of flooding
recharged groundwater stores
connectivity between aquatic habitats
soil replenishments
migration, breeding dispersal for many species
how have negative impacts on the environment made worst by humans
removal of soil and sediment by floodwaters can lead to the eutrophication of water bodies, same flood water can leach polluatnts intot the water which causes diaster effects for the wildlife and can weaken and kill trees
causes of the UK floods
prolonged heavy rainfall
most devasting uk floods
summer of 2007
winter of 2015-2016
2016 UK Flood
large areas of uk recieved x2 than normal rainfall
Carlise Cumbria worst hit
what was too blame for the UK floods
global warming
budget cuts in amount of money being spent on flood protection
poor land management - blocked ditches
Evaporation - Inputs and Outputs
increasing over lage areas of Asia and North America
Transpiration
linked to vegetation changes, links to soil moisture and precipitation
Precipitation
precipitation increases in tropics and high latitudes
precipiation decrease areas 10 degrees and 30 degress north and south of equator
length and frequency of heatwaves increasing in some locations is resulting in the increased occurrence of drought
With climate warming, more precipitation in northern regions is falling as rain rather than snow
Surface Run off and stream flow - Stores
More low flows (droughts) and high flows (floods)
Increased runoff and reduced infiltration
Stores Groundwater flow
uncertain because of absraction from humans
Resorivor, Lakes, and wetland storage - Flows
Changes in wetland storage cannot be conclusively linked to climate change
It appears that storage is decreasing as temperatures increase
Soil Moisture - Flows
soil moisure increase as precipiation increase
little change as high precipiation and evaporation cancelling out
Permafrost - Flows
Deepening of the active layer is releasing more groundwater
Methane released from thawed lakes may be accelerating change
Snow - Flows
sprint melt starting earlier
decreasig temporary store
decreasing length of snow season
what effects stores and flows
climate change
Glacier Ice
decreasing store
evidence of glacier retreat and thining since 1970
Less accumulation because more precipitation is falling as rain
Oceans
rising sea level
strorage capacity increasing due to meltwater
ocean warming = evaporation more
ocean warming leads to generations of more cyclones
factors that lead to diminshing water supply and increased uncertainity
More frequent cyclone and monsoon events threaten water supplies intermittently
global warming = less rainfall in areas
Depleted aquifers lead to problems with groundwater
Impact of oscillations ENSO, is leading to increasingly unreliable patterns of rainfall less predictable monsoons
problems with this forecasting of possible changes to the hydrological cycle
the difference between long term climate change and short term oscillations associated with El Niño events.
why is uncertantiy rising
scientists reserach is unable to make confident forecasts about future availability of water
Nile Length
6700km
how many countries compete for the Nile
11 countries
how many people live within the Nile
2017 -300 million
what is the nile expected to generate
HEP
flashpoints at the nile
dams and barrages bult in Sudan and Ethopia that depreive downstream Egypt of its far share of Nile wateer
how does irrigation cause droughts
too much water usage overwatering crops
where was water privatised
Bolivia
why was water being privatised thought to be a good idea
people should pay for their water for what it costs to capture, treat it and provide it.
what did the world bank and the IMF do with the privateism
developed a structural adjustment programme which claimed it would help developing countries to overcome debt issues
what were the impacts of privatisation
riots
important people dying
can’t afford water
can’t collect rainwater
Where was the conflict in a country
Colorado River
why was their conflict about Collard River
Upper basin states such as New Mexico, Wyoming
as they grow their crops
what did the law of the river suggest
divided the river into Upper base states who had responsiblily to supply the lower states
what has happened over the time
new treaties have been singned, include New Mexico
what has changed the treaties
population, industry and climate
where does there river nile flow
south to north
what countries are in the nile
Egypt, eritrea, Dr,Congo, Burundi, Ethiopia, Sudan, Kenya
why is their conflict on the nile - north countries
countries in the north part of the river want more due to tourism and population and developed more
why do southern countries want more water in the nile
to be able to actually live and keep it
what does the collard river separate
Mojave and the Sonoran in Arziona
why may conflict occur on the colardo river
one state getting more than the other, disputes between states
why may conflict occur
If countries in the south put a dam restricting water flow, Egypt would go to war to destroy the dam and get their water
Arizona and California dispute
Arizona felt the need to protect its right against upstream greed
califrona was growing fast and in need of water to supply its cities and intensive agriculture
