The hydrosphere Flashcards
the hydrological cycle is in a state of…
dynamic equilibrium
Human activities can alter the hydrological cycle by altering… (2 things)
- residence time in reservoirs
2. quantities of H2O in reservoirs
definition of a reservoir and name 3 to do with the hydrological cycle
the storage location for a material i.e. ocean, permafrost and rivers and lakes
the difference between percolation and infiltration and what are these examples of?
percolation = movement of H2O within the soil infiltration = H2O entering the soil
Name the 5 anthropogenic impacts on the hydrological cycle `
- afforestation
- deforestation
- agriculture
- urbanisation
- climate change
how does afforestation affect the cycle?
- increases interception so less infiltration/percolation, reduces soil moisture
- increases transpiration so more evap.
how does deforestation affect the cycle?
- decreases interception, increases infiltration
- decrease in transpiration so less evap.
(opposite of afforestation)
how does agriculture affect the cycle?
- irrigation increases evap. so increases quantities in the atmosphere
- soil can be compacted by farm machinery, so less infiltration
how does urbanisation affect the cycle?
impermeable surfaces i.e. concrete = less infiltration, more runoff
how does climate change affect the cycle?
- increased greenhouse gases, increase temp. increased evap. increase in atmosphere reservoir
- land is drier, less infiltration, less in groundwater reservoirs
- increase in evap. melting of land ice so increase quantities of ocean and lake reservoirs
definition of residence time
average length of time H2O stays in a reservoir before moving to another
what are the 3 strategies that allow sustainable exploitation of H2O sources and summaries what they do.
- inter basin transfer = pipes/canals used to transfer H2O from one area of surplus to an area of shortage (done in Australia, and wales to England)
- artificial recharge = surplus H2O left in lagoons so infiltrate gradually. Used in wet seasons where infiltration capacity has been exceeded
- river regulation reservoirs = reservoirs can regulate extreme flow. Holding back the H2O in times of surplus and releases H2O when less rainfall
definition of desalination
uses high pressure (and so lots of energy needed so very expensive) to desalinate sea H2O into drinking H2O
why the unsustainable use of an aquifer is bad? (4 main points)
- can lower H2O table so causes saltwater incursion
- can cause subsidence (damages infrastructure)
- if extraction rate exceeds recharge rate volume that can be extracted reduced
- many lakes/rivers/marshes fed by groundwater from aquifers, so if the H2O decreases aquatic and semi aquatic organisms can die out
why the unsustainable use of a reservoir is bad?
- can be abstructive: significantly lower downstream flow
- sedimentation in reservoir occurs: less sediment to fertilise flood plain and build up river banks to reduce erosion
- changes in flow fluctuations and can act as a wildlife barrier i.e. for salmon migration
- microclimate can change i.e. more evap. more rainfall. less friction, increase in wind
what is the role of the thermohaline circulation?
- brings warm H2O from the Caribbean and deposits it in in the North Atlantic (using the density of H2O, increase the salinity and decrease the temp, H2O becomes more dense)
- releases lots of heat into atmosphere brings warm air
- without it it would be significantly colder in europe
Name the steps in order to treating contaminated H2O (9 steps)
- screens
- sedimentation
- Aeration
- . flocculation/ coagulation
- filtration
- activated carbon filters
- sterilisation
- ph control
- fluoridation
what does screens and sedimentation do? (H2O treatment)
- screens = removes litter and vegetation
2. sedimentation = allows suspended solids to settle
what does aeration do in H2O treatment?
adds O2 to the H2O (high O2 dissolved levels) which allows for aerobic respiration which prevents the smell of hydrogen sulphate
what does flocculation/coagulation do in H2O treatment?
adding flocculant i.e. aluminum oxide: it neutralises charges by breaking electrostatic charges on clay particles so they can clump together and settle.
what does filtration do in H2O treatment?
slow flow of H2O thru sand/gravel to get rid of solids/ bacteria
What do activated carbon filters do in H2O treatment?
remove organic material like pesticides using activated carbon particles
what does sterilisation do in H2O treatment?
addition of ozone, chlorine or UV light to sterilise/remove pathogens
what does pH control do in H2O treatment?
addition of crushed lime to increase pH (chlorine makes it acidic)
what does fluoridation do in H2O treatment?
fluorides are added to improve dental health
Explain how using water meters and low h2o use appliances help save H2O
- water meters = charges the consumer for how much H2O they use so encourages them to save H2O
- appliances use less H2O
What is greywater and how is it used to save H2O?
greywater is H2O that has been used but is relatively clean (recycled). there is no fecal matter or sewage in it in it. it is used for flushing toilets and garden uses
Unexploited aquifers can…
increase H2O supplies
how is rainwater catchment important to save H2O?
- reduces heavy flooding in areas
- can be used to water gardens etc.
- important in rural areas where there is no h2O supply
How can reservoirs and estuary barrages manage H2O?
- reservoir = can allow storage of H2O in times of surplus so can be used in times of shortages
- estuary barrage = freshwater reservoir created by building a dam across an estuary
problems with estuary barrages (3 points)
- they are an obstacle for shipping
- can be polluted by catchment area
- can change inter-tidal habitats
How does xeriscaping help save H2O?
planting vegetation like xerophytes that don’t need lots of H2O to survive
How does low volume irrigation help save H2O?
drip irrigation = give H2O straight to plants, less evap, less H2O loss
What is the best topography for choosing a location for a reservoir?
deep basin with a narrow exit: so can hold a large volume of H2O, less reservoir construction (less expensive)
the ground underneath a reservoir should be permeable and have no seismic activity t or f?
F there should be no seismic activity AND rock should be impermeable
H2O from rivers must be carried __________ into reservoirs. River in flow must be _______. Also climate should not be too _____ as this will cause excessive evap.
- downstream
- regular
- hot
Pollution risk in the reservoirs catchment area should…
…not pose a pollution risk (pesticides/industrial contaminants i.e. oil)
…not have sewage
…not be surrounded by forest, lots of dead vegetation decays anaerobically,methane released
if there is high risk of soil erosion in catchment area of the reservoir this can…
increase turbidity, increasing sedimentation in the reservoir, decreasing the volume it can hold
before building the reservoir have to make sure that the land you are flooding is …
is of lower value, not important
near reservoirs, there must be…
the correct infrastructure i.e. roads for workers to access and transport, building materials/machinery. Convenient site near area of demand
