water cycle Flashcards
what are the major stores of water globally
lithosphere
hydrosphere
atmosphere
cryosphere
where is water stored within each sphere
lithosphere - rocks , soil , groundwater
hydrosphere - rivers , lakes , sea, oceans
cryopsphere- frozen ice, glaciers, permafrost
biosphere - plants and living organisms
atmosphere - water vapour
how much of earths water is fresh
2.5 %
what is an aquifer and and its characteristics
rocks deep bellow the surface forming underground reservoirs.
store over 30% of all fresh water
chalk and sandstone are common rocks - contains air pockets allowing water to pass through
fossil aquifers - found in deserts , formed when climate was wetter thousands of years ago .
over abstraction has meant they have become salty
salt water has infiltrated into the rocks
what is sublimation and desublimation
sublimation - ice turning to water vapour
desublimation - water vapour to ice
what are input for a drainage basin
precipitation
outputs from a drainage basin
evaporation - surface storage evaporates to the atmosphere
transpiration - plants loosing water through the stomata and leaves
evapotranspiration - total output in the system
flows within a drainage basin
stem flow - water flowing down grasses , stems and tree trunks.
infiltration - water soaking into the soil
overland flow - when stores are full , overland flow will begin on slopes
through flow - any lateral movement of soil water downslopes is called through flow. slower than overland flow
percolation - after infiltration. water moves vertically down through the soil and unsaturated rocks. water is held between rocks as ground water
groundwater flow - slow movement. vertically and laterally in saturated rock. - aquifers
stores within a drainage basin
interception - leaves, branches , intercept the rainfall .
vegetation storage - water removed from soil and stored in the vegetation
soil storage - amount of water stored in soil . pore spaced that are filled with air can be filled with water.
ground water - held in the pores of permeable rocks bellow the soil storage. - aquifers
what happens to the water balance in winter
surplus of water
- low temperatures
- low evapotranspiration
- low interception
- high precipitation
what happens to the water balance in the summer in the UK
water deficit
- high temperatures
- high evapotranspiration
-high precipitation - high interception
what is the water balance
balance between inputs and outputs
winter - wet season , precipitation exceeds evapotranspiration - water surplus
drier seasons - summer , precipitation is lower than evapotranspiration. ground stores are depleted
revise flood hydrographs
how do clouds form
water is all around us in from of gas particles - water vapour
so are particles floating in air - dust and salt - aerosols
when air cools water vapour sticks to the aerosols - condensation
when these droplets start sticking to other droplets clouds form
when drops group together they grow heavier and gravity pulls them as raindrops
what is evaporation
occurs when water is heated. water changes state from a liquid to a gas
what is condensation
reverse of evaporation
as water rises it cools and changes back into a liquid
what natural factors effect the water cycle
precipitation
vegetation cover- interception and transpiration
evaporation
soil water - dry soils encourage infiltration, saturated soils or hard soils means more overland flow
river channel flow - summer - low flow and in winter high flow
what human activities affect change in the water cycle
urbanisation - water can not infiltrate into the soil which increases overland flow
deforestation - leads to strafe run off
how does farming influence the water cycle
through irrigation or land drainage
cover soil with plants so higher infiltration and higher soil water rates. this reduces run off
what is water abstraction and why does it happen
extraction of water from rivers or groundwater aquifers
for irrigation , industry and domestic purposes
negative impacts o water abstraction
aquifers can become depleted and contaminated by salt water
effects local water cycles
how does deforestation negatively impact the water cycle
evaporation reducues - atmoopshere becomes less humid
few trees means more water reaches the ground- more overland flow
runoff rates increase- increasing flood risk
soil exposed to the sun- becomes dry and will erode
few trees remain so little interception - less evaporation of trees. transpiration will be 0
how does soil drainage and farming negatively impact the water cycle
how does water abstraction negative impact the water cycle
