✅C&W 3.1.1.2 - The Water Cycle Flashcards
What is precipitation?
Transfer of water form the atmosphere to the ground. It can take the form of rain, snow ,hail, dew etc
What is interception? How does it vary with density?
Water intercepted and stored in the leaves of plants
Denser - more interception
58% in rain forest, 22% in deciduous forest
What is throughflow?
Water flowing through soil towards the river channel
What is infiltration? What affects it
Transfer of water from the ground surface into soil where it may then percolate into underlying rocks
Gravity, soil porosity, capillary action
What is percolation?
Water soaking into rocks
What is groundwater flow?
Transfer of water very slowly though rocks
River flows: downstream vs Upstream
Slowest at the side with friction
Downstream: laminar flow, fast and smooth
Upstream (nearer source): eddies, like small whirlpool, due to friction with angular bed
Causes of deposition
Lower gradient, less discharge, shallow, increased load, lower velocity (friction), flocculation
What if flocculation
Process where small particles suspended in water lump& form larger pieces
Due to when salt water meets fresh water
Coagulation of particles makes them sink, can cause mudflats
Changes to local water cycle: Deforestation
less interception, more runoff, flooding
less soil, fewer plants, less transpiration, less rain in LT
Changes to local water cycle: Storm events
saturation, more runoff
Changes to local water cycle: seasonal changes
Spring: more vegetation, interception,
Summer: less rain, harder ground, more runoff when rains
Autumn: less vegetation, less interception, more runoff
Winter: hard ground, runoff
Changes to local water cycle: agriculture
pastoral farming: animals trample ground, more runoff
Arable: more vegetation, more interception, less runoff + ploughing means looser soil and more interception
Irrigation: ground water depletion
Changes to local water cycle: urbanisation
impermeable ground, runoff, lower lag time, higher flood risk, flash floods
Although drains help
What is surface tension?
How the molecules on the surface of water behave and how tightly they are held together by hydrogen bonds
What is atmospheric water?
Water found in the atmosphere- mainly water vapour
0.04% of all water
Short residency time, dynamic equilibrium
As temps rise, more water vapour stored (hot air stores more water): for every 1C temp rise, atmospheric water store rises 7% - more intense rainfall
What is cryospheric water?
The water locked up on the Earth’s surface as ice
5 stores of cryospheric water
permafrost- ground which stays at/below 0°C for at least 2 years. Locks up CO2
alpine glaciers
sea ice
ice sheets- glacial land over 50,000 km^2. E.g, Antarctica
ice caps
as cryosphere decreases, oceanic increases
Positive feedback with albedo effect
albedo, ice reflects sunlight, so less ice means less reflection, means more heat absorption, more melting
What is the hydrosphere?
A discontinuous layer of water at or near the Earth’s surface waters, groundwater held in soils and rock and atmospheric water vapour
What is oceanic water?
Acidity?
The water contained in the Earth’s oceans and seas
Salty, but has decreased in pH due to fresh water (ice caps) melting into it. 8.25 pH to 8.14 pH over 250 years
Damaging ecosystem
What is terrestrial water?
This consists of groundwater, soil moisture, lakes, wetlands and rivers
4 stores of terrestrial water
Surface water- free flowing like rivers- largest river is the Amazon, discharge 209,000m^3/s- 0.0002% of all water
Ground water- 20% of fresh water, but decreasing due to extraction from agriculture
Soil water
Biological water- very little, not long residency time
Which is the largest store of water?
Oceanic water, 97% of all water
Where is most of the freshwater on Earth stored?
In the Antarctic and Greenland ice sheets
Parts of a river
Source: start of river, supply
River channel: space between bed& banks (main river)
Confluence: where tributary meet river channel
Tributary: smaller side river
What is a drainage basin
The area of land drained by a river and all it’s tributaries. AKA catchment area
They are all next to each other in one cascading system of open systems
What are inputs into the drainage basin?
Precipitation
Energy from the sun
What are stores in the drainage basin?
Lakes Soil/Ground water Interception/vegetation River flow Surface flows
What are transfers in the drainage basin?
Ground water flow
Percolation
Transpiration
Precipitation
What are the outputs from the drainage basin?
River discharge
Evapo-transpiration from vegetation, water
Water vapour
What is the fastest movement of water through the drainage basin?
Along the surface where there are relatively few obstacles in the way of the water