The hydrosphere

Question 1

the hydrological cycle is in a state of…

Answer 1

dynamic equilibrium

Question 2

Human activities can alter the hydrological cycle by altering… (2 things)

Answer 2

1. residence time in reservoirs

2. quantities of H2O in reservoirs

Question 3

definition of a reservoir and name 3 to do with the hydrological cycle

Answer 3

the storage location for a material i.e. ocean, permafrost and rivers and lakes

Question 4

the difference between percolation and infiltration and what are these examples of?

Answer 4

percolation = movement of H2O within the soil 
infiltration = H2O entering the soil

Question 5

Name the 5 anthropogenic impacts on the hydrological cycle `

Answer 5

1. afforestation
2. deforestation
3. agriculture
4. urbanisation
5. climate change

Question 6

how does afforestation affect the cycle?

Answer 6

• increases interception so less infiltration/percolation, reduces soil moisture
• increases transpiration so more evap.

Question 7

how does deforestation affect the cycle?

Answer 7

• decreases interception, increases infiltration
• decrease in transpiration so less evap.
  (opposite of afforestation)

Question 8

how does agriculture affect the cycle?

Answer 8

• irrigation increases evap. so increases quantities in the atmosphere
• soil can be compacted by farm machinery, so less infiltration

Question 9

how does urbanisation affect the cycle?

Answer 9

impermeable surfaces i.e. concrete = less infiltration, more runoff

Question 10

how does climate change affect the cycle?

Answer 10

• 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

Question 11

definition of residence time

Answer 11

average length of time H2O stays in a reservoir before moving to another

Question 12

what are the 3 strategies that allow sustainable exploitation of H2O sources and summaries what they do.

Answer 12

1. 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)
2. artificial recharge = surplus H2O left in lagoons so infiltrate gradually. Used in wet seasons where infiltration capacity has been exceeded
3. river regulation reservoirs = reservoirs can regulate extreme flow. Holding back the H2O in times of surplus and releases H2O when less rainfall

Question 13

definition of desalination

Answer 13

uses high pressure (and so lots of energy needed so very expensive) to desalinate sea H2O into drinking H2O

Question 14

why the unsustainable use of an aquifer is bad? (4 main points)

Answer 14

1. can lower H2O table so causes saltwater incursion
2. can cause subsidence (damages infrastructure)
3. if extraction rate exceeds recharge rate volume that can be extracted reduced
4. many lakes/rivers/marshes fed by groundwater from aquifers, so if the H2O decreases aquatic and semi aquatic organisms can die out

Question 15

why the unsustainable use of a reservoir is bad?

Answer 15

1. can be abstructive: significantly lower downstream flow
2. sedimentation in reservoir occurs: less sediment to fertilise flood plain and build up river banks to reduce erosion
3. changes in flow fluctuations and can act as a wildlife barrier i.e. for salmon migration
4. microclimate can change i.e. more evap. more rainfall. less friction, increase in wind

Question 16

what is the role of the thermohaline circulation?

Answer 16

• 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

Question 17

Name the steps in order to treating contaminated H2O (9 steps)

Answer 17

1. screens
2. sedimentation
3. Aeration
4. . flocculation/ coagulation
5. filtration
6. activated carbon filters
7. sterilisation
8. ph control
9. fluoridation

Question 18

what does screens and sedimentation do? (H2O treatment)

Answer 18

1. screens = removes litter and vegetation

2. sedimentation = allows suspended solids to settle

Question 19

what does aeration do in H2O treatment?

Answer 19

adds O2 to the H2O (high O2 dissolved levels) which allows for aerobic respiration which prevents the smell of hydrogen sulphate

Question 20

what does flocculation/coagulation do in H2O treatment?

Answer 20

adding flocculant i.e. aluminum oxide: it neutralises charges by breaking electrostatic charges on clay particles so they can clump together and settle.

Question 21

what does filtration do in H2O treatment?

Answer 21

slow flow of H2O thru sand/gravel to get rid of solids/ bacteria

Question 22

What do activated carbon filters do in H2O treatment?

Answer 22

remove organic material like pesticides using activated carbon particles

Question 23

what does sterilisation do in H2O treatment?

Answer 23

addition of ozone, chlorine or UV light to sterilise/remove pathogens

Question 24

what does pH control do in H2O treatment?

Answer 24

addition of crushed lime to increase pH (chlorine makes it acidic)

Question 25

what does fluoridation do in H2O treatment?

Answer 25

fluorides are added to improve dental health

Question 26

Explain how using water meters and low h2o use appliances help save H2O

Answer 26

1. water meters = charges the consumer for how much H2O they use so encourages them to save H2O 2. appliances use less H2O

Question 27

What is greywater and how is it used to save H2O?

Answer 27

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

Question 28

Unexploited aquifers can...

Answer 28

increase H2O supplies

Question 29

how is rainwater catchment important to save H2O?

Answer 29

1. reduces heavy flooding in areas 2. can be used to water gardens etc. 3. important in rural areas where there is no h2O supply

Question 30

How can reservoirs and estuary barrages manage H2O?

Answer 30

1. reservoir = can allow storage of H2O in times of surplus so can be used in times of shortages 2. estuary barrage = freshwater reservoir created by building a dam across an estuary

Question 31

problems with estuary barrages (3 points)

Answer 31

1. they are an obstacle for shipping 2. can be polluted by catchment area 3. can change inter-tidal habitats

Question 32

How does xeriscaping help save H2O?

Answer 32

planting vegetation like xerophytes that don't need lots of H2O to survive

Question 33

How does low volume irrigation help save H2O?

Answer 33

drip irrigation = give H2O straight to plants, less evap, less H2O loss

Question 34

What is the best topography for choosing a location for a reservoir?

Answer 34

deep basin with a narrow exit: so can hold a large volume of H2O, less reservoir construction (less expensive)

Question 35

the ground underneath a reservoir should be permeable and have no seismic activity t or f?

Answer 35

F there should be no seismic activity AND rock should be impermeable

Question 36

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.

Answer 36

1. downstream 2. regular 3. hot

Question 37

Pollution risk in the reservoirs catchment area should...

Answer 37

...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

Question 38

if there is high risk of soil erosion in catchment area of the reservoir this can...

Answer 38

increase turbidity, increasing sedimentation in the reservoir, decreasing the volume it can hold

Question 39

before building the reservoir have to make sure that the land you are flooding is ...

Answer 39

is of lower value, not important

Question 40

near reservoirs, there must be...

Answer 40

the correct infrastructure i.e. roads for workers to access and transport, building materials/machinery. Convenient site near area of demand