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