Geography - Water Cycle EQ1 Flashcards
What is systems approach
A way of studying natural processes by looking at the balance of inputs and outputs, and how water moves between stores.
What are stores
Reservoirs where water is held.
What are fluxes
Rate of flow between stores.
What are processes
The physical mechanisms that drive fluxes of water between stores.
What is the cryosphere
Areas of earth where water is frozen.
What is blue water
Water stored in rivers, streams and lakes - visible part of hydrological cycle.
What is green water
Water stored in soil and vegetation - invisible part of hydrological cycle.
What is residence time
Average amount of time a water molecule will spend in a store.
What is fossil water
Ancient, deep groundwater from former wetter periods.
What is transpiration
The diffusion of water from vegetation to atmosphere, involving a change from liquid to gas.
What is groundwater flow
The slow transfer of percolated water underground through previous rocks.
What is throughfall
when rainfall persists and when water drops from leaves, twigs, needles.
What is percolation
Deep transfer of water from surface to rocks below.
What is evapotranspiration
Combined effect of evaporation and transpiration.
What is river regime
Annual variation in discharge or flow of a river at a particular point, usually measured in cumecs.
What are examples of stores
Ocean, Ice, Groundwater, Rivers + Lakes and Soil moisture - Most to Least sig
What are examples of fluxes
Ocean evaporation. Ocean precipitation and Land precipitation -Most to Least sig
What is a system
Any set of interrelated components that are connected together, characterised by inputs, outputs, stores and processes.
What is a closed system
Where there is a transfer of energy but no external inputs or outputs - no matter can enter.
What is an open system
Receives inputs from and transfers outputs of energy and matter to other systems.
What is the hydrological cycle
A closed system, driven by solar energy and GPE, fixed amount of water, total of all processes in which water circulates around entire earth.
What are the 4 main stores of water
Oceans, cryosphere, terrestrial surface water, atmosphere.
What is interception
Where vegetation catches/intercepts water from rainfall
What is the drainage basin
An area of land where water from rain or snow melt drains downhill into a body of water such as a river or lake.
How does relief affect the drainage basin
Impacts amount of precipitation, slopes affect runoff.
How does climate affect the drainage basin
Influences type and amount of precipitation and amount of evaporation.
How does vegetation affect the drainage basin
The presence or absence has major impact on interception, infiltration and overland flow.
How does geology affect the drainage basin
Impacts subsurface processes like percolation and groundwater flow.
How does soil affect the drainage basin
Determines amount of infiltration and throughflow.
What is convectional rainfall
Common in tropical areas, land becomes warm, air expands and rises, air cools - ability to hold water vapour decreases, condensation occurs and clouds develop.
What is cyclonic rainfall
Air is warm - lighter and less dense, forced to rise over colder and denser air, as it rises - air cools and ability to hold water vapour decreases, condensation occurs and clouds develop.
What is orographic rainfall
Air is forced to rise over a barrier, cools and condenses, downwind slope receives little rain - called rain shadow effect.
What are the Amazon’s characteristics
Has dense vegetation - high rates of interception and evapotranspiration, high humidity and convectional rainfall, self sustaining cycle.
What has human interaction done to the Amazon
Over 20% has been destroyed in last 50 years - cattle ranching, commercial agriculture and general development, the deforestation has led to decreased precipitation and evapotranspiration, has increased river discharge and runoff.
How does the Amazon affect the water cycle
Contains 60% of world’s rainforests, trees are ‘green lungs’ - remove CO2 and photosynthesise, store carbon, destruction - reduces carbon store capacity, adds to greenhouse gases - bad for drought.
How does cloud seeding act as a human disruption
Affects precipitation, changes amount or type of precipitation, has reliable results yet effectiveness still debated, used in China Olympics 2008 to clear air pollution.
How does deforestation and afforestation act as human disruption
Affects interception, deforestation leads to evapotranspiration also increases surface run off, increases flooding potential, research in Nepal shows negative impacts of deforestation.
Afforestation reverses the impacts by trapping silt, lengthens lag time, research in Plynlimon area showed when there was young trees there’s increased surface run off.
How does urbanisation act as a human disruption
Affects interception and infiltration, urbanisation creates impermeable surfaces, stream discharge increases, surface runoff and throughflow increase, across UK increased flood risks in many cities.
How does dam construction act as human disruption
Affects evaporation, increase surface water stores and evaporation, reduces downstream river discharge, Lake Nassey in Egypt estimated to have loss 10-16 billion cubic metres every year.
What is the water budget
Change in storage - Precipitation (P) - (Run off (Q) + Evapotranspiration (E))
What is a positive balance
Indicates inputs are greater than outputs, water will be stored.
What is a negative balance
Indicates outputs are greater than inputs, stores will be depleted.
What is a surplus
If precipitation exceeds evapotranspiration and excess water hasn’t been used, there’s a surplus.
What’s a deficiency
Evapotranspiration exceeds precipitation, soil moisture has been used up.
What is recharge
Replacement of water lost from soil during drier periods.
What is soil moisture utilisation
Soil water is used by people and plants, reducing the amount remaining in the soil and river channels.
What is field capacity
Maximum amount of water soil can hold.
What is a river regime
The annual variation in discharge or flow of a river at a particular point or gauging station.
What affects a river regime’s characteristics
Size of the river, amount of precipitation, temperature, geology, overlying soils, amount of vegetation cover.
What is storm hydrograph
Hydrograph is a graph showing the changes in the discharge of a river over a short period of time.
What is lag time
The time between peak rainfall and peak discharge.
What is baseflow
The normal flow of a river.
What’s a flashy hydrograph
Steep rising and falling limbs, high peak discharges. deforestation and urban areas.
What is a subdued hydrograph
Long lag time, low peak discharge, flood defences.
