a system
an assemblage of interrelated parts that work together. a series of stores and components and have flows between them
cascading system
outputs from one system becomes the input for the adjacent system
interception
raindrops fall on vegetation, preventing it from reaching the soil & river
leaf drip
water from leaves to soil
capillary uptake
water on roots
stem flow
water reaches the ground by flowing down trunks or stems or by dropping off leaves
infiltration
the passage of water vertically into the soil. in filtration cannot occur if soil is saturated
Percolation
a vertical movement of water from above the water table to below the water table. of the bedrock is impermeable, no percolation can occur
surface runoff (overland flow)
occurs during heavy rainfall when the ground is saturated or if surfaces are impermeable. rate except for in urban areas
through flow
water flows laterally through the soil to channel, mainly along "pipes" caused by animal activity or growth of plant roots
ground water flow
water moves laterally at a very slow rate. it transfers water to the river through their bed and banks long after a rainfall event
hydrostatic pressure
water goes up to river defying gravity
channel flow
precipitation directly entering the river channel
lithosphere
all rocks/ soils/ ground water stores found on the earth underground
Hydroshpere
all water stored on the earth. mostly found in ocean and seas, rivers and lakes. can also be found as underground water stores (aquafers)
96.5% of water is salt water
2.5% is fresh water
atmosphere
all water held in the atmosphere held as water vapour e.g. clouds
the atmosphere contains 12,900km3 of water as vapour - only 0.4% of earths total
crysphere
all ice stored on earth. mostly in Antarctica, Greenland, Canada, Russia, tops of mountains , sea ice, permafrost, ice caps, ice sheets, alpine glaciers
porous soils
holds very little water but allows the transfer of water
clay soils
store a huge amount of water but allows very little transfer
store residence time
the amount of water in a store divided by the rate of addition of water to the store or the rate of loss from it
fusion
the substance changes from a solid to liquid
freezing
the substance changes from a liquid into a vapour
condensation
substance changes from a vapour to a liquid
evaporation rates depend on:
-amount of solar energy
-availability of water
-humidity in the air
dew point
the temperature at which water vapour in the air turns into liquid water
cryospheric processes
-ice is a large store of water - over time has fluctuated lots
in the short term snow accumulates and adds to the mass of the glacier or ice sheet. annual changes in cryosphere change between winter & summer
orographic (relief rainfall)
air rises over mountains: cools & condenses
convection rainfall
air heats and rises. when air rises it cools and condenses. most common on the equator. often causes heavy rainfall
frontal rainfall
when warm and cold air meets. warm air forced over cold air, rises and condenses
drainage basin
the area of land drained by a river and it's tributaries. it includes water found on the surface and soil near surface geology. an open system/ cascading system
water balance/ budget
within a drainage basin the balance between inputs & outputs
rivers regime
discharge levels rise and fall in a river, often showing an annual pattern
water balance equation
precipitation(P) = discharge(Q) + evapotranspiration(E) +/- changes in storage
hydrograph equation
discharge = cross sectional areas × velocity in m3/s / cumecs
lag time
the time difference between the peak if the rain storm and the peak flow of the river.
a longer lag time = less prone to flood
features of a drainge basin
-source
-confluence
-tributary
-river channel
-mouth
-water shed
water balance
within a drainage basin the balance between inputs & outputs
run off variation and hydrographs
river flow is studied by measuring discharge (volume of water passing a measurement point in a given time). this is measured by using gauging stations
a flashy hydrograph
short lag time, high peak, steep rising and falling limbs
a subdued hydrograph
long lag time, low peak, gently rising and falling limbs
short lag time
-saturated soil
-lots of tributaries (high drainage density)
-lots of intense rainfall
-urbanisation
-impermeable surfaces
-agriculture
-steep soil angles
-deforestation
long lag time
-unsaturated soil
-no/little tributaries
-little rainfall
-small drainage basin
-permeable soils
-lots of vegetation
-rural
accumulation
inputs to a glacial system due to snow fall
ablation
output of a glacial system due to melting
sublimation
ice changing directly into water vapour
physical factors affecting hydrographs
-drainage basin density and size
-drainage basin relief/slope
-drainage basin shape
-geology
-vegetation
-saturation level by antecedent rainfall
human factors affecting hydrographs
-deforestation
-afforestation
-urban growth
-agriculture
-water abstraction
freshwater vs salt water %
oceans - 97%
freshwater 3%
freshwater storage %
rivers and ice caps - 69%
groundwater - 30%
surface/other freshwater - 1%
processes involved within the transfers of carbon
-photosynthesis
-respiration
-decomposition
-combustion
-burial and compaction
positive feedback example
increase in temperature ->increase in oceanic temperature -> dissolved co2 released from warmer oceanic -> increase in co2 -> further atmospheric warming
cloud formation
visible masses of water droplets or ice crystals held in the atmosphere. form when:
-air is saturated either bc it has cooled below the dew point or evaporation means the air has reached its maximum water holding capacity
-condensation nuclei are present
how does the process of evaporation and condensation relate to the formation of clouds
water evaporates from the surface of the earth and condenses around the nuclei to form visible water droplets
how does the process of evaporation and condensation relate to the formation of rainfall
water evaporates into the atmosphere, condensation occurs when air temperature reaches its dew point or due to adiabatic cooling
how does temperature affect evapotranspiration
warmer temperatures lead to higher rates of evapotranspiration as warm air can hold more water vapour
how does wind affect evapotranspiration
evapotranspiration increases as wind moves humid air away and the air does not become saturated as quickly.
how does humidity affect evapotranspiration
the more humid it is, the lower the evapotranspiration as the air becomes saturated quickly