Chapter 5 - The Hydrosphere

Question 1

What are 4 reasons that the global demand for water is increasing ?

Global demand for water

Answer 1

• increase in population
• increase in per-capita use with increased affluence
• Increased irrigation of farmland
• industrialisation

Question 2

How can deforestation affect the hydrological cycle ?

Human impacts on the hydrological cycle

Answer 2

Less trees means that there is a reduction of precipitation downwind because more water infiltrates through soil or runs of into rivers

Question 3

what is one way that agriculture affects the hydrological cycle ?

Human impacts on the hydrological cycle

Answer 3

soil compacted by heavy machinery cannot be infiltrated by water easily so soil moisture drops and runoff increases

Question 4

how does urban development effect the hydrological cycle ?

Human impacts on the hydrological cycle

Answer 4

Urban expansion means that there is a larger area of impermeable surfaces which will increase runoff

Question 5

what is one way global climate change affects the hydrological cycle ?

Human impacts on the hydrological cycle

Answer 5

higher global temperatures affects the rate of melting, evapouration and condensation which all affects the timing and rate of precipitation

Question 6

How can building a resevoir alter the habitat ?

Water abstraction: Rivers & Reservoirs

Answer 6

flooding destroys previous habitats but also could create new valuable ones

Question 7

How can building a resevoir alter the wildlife barrier ?

Water abstraction: Rivers & Reservoirs

Answer 7

dams & reservoirs act as barriers to wildlife that may have previously migrated down the river

Question 8

How can building a resevoir alter the sedimentation ?

Water abstraction: Rivers & Reservoirs

Answer 8

sediments reaching the reservoir will settle there and not travel further downstream. Can deprive river banks further downstream of sediment making them more vulnerable to erosion

Question 9

What are 2 ways that resevoirs may be used to provide water ?

Water abstraction: Rivers & Reservoirs

Answer 9

• regulate river flow (holding back water at times of surplus etc)
• Changes to flow fluctuations can change river erosion & sedimentation so therefore development of meanders

Question 10

Describe the rivers flowing into the Aral sea

over-exploited rivers EXAMPLE

Answer 10

• Rivers supplying the Aral sea flow through central Asia
• Since 1960s huge irrigation schemes for growing cotton & rice has caused river flow into the sea to decline, sometimes to zero
• Area of lake was reduced by 90% and pollution by pesticides, fertilisers and industrial waste caused serious issues
• Disagreements & conflicts between the countries that the river runs through
• Abstraction for irrigation reduces flow downstream

Question 11

What is an aquifer ?

Water abstraction: Aquifers

Answer 11

body of rock which holds water that’s exploited as a resource

Question 12

What are 3 features of an aquifer ?

Water abstraction: Aquifers

Answer 12

• porosity
• permeability
• assosiated geological structures

Question 13

how are aquifer water levels depleated ?

Water abstraction: Aquifers

Answer 13

If the rate of extraction exeeds rate of recharge

Question 14

Normally how does aquifer recharge take place ?

Water abstraction: Aquifers

Answer 14

Precipitation lands on the soil and infiltrates and perculates through the soil

Question 15

why are changes in surface hydrology a consequence of overexploited aquifer ?

Water abstraction: Aquifers

Answer 15

lead to lowering of the water table, this can reduce supply of water to wetlands, lakes, rivers etc and they may dry up

Question 16

why are changes in Subsidence a consequence of overexploited aquifer ?

Water abstraction: Aquifers

Answer 16

there are air spaces left where water previously was, these cannot support the weight of rock above so the ground becomes compacted (causes subsidence at the surface which damages pipes and buildings)

Question 17

why are Salt water incursion a consequence of overexploited aquifer ?

Water abstraction: Aquifers

Answer 17

if the aquifer is over exploited seawater may flow into the aquifer to replace lost water (Salt makes aquifer water unsuitable for irrigation as will kill plants by osmosis dehydration)

Question 18

why are Reduced supplies a consequence of overexploited aquifer ?

Water abstraction: Aquifers

Answer 18

if extraction rate exceeds recharge, volume available for abstraction will be reduced

Question 19

Describe the features of the north china plain aquifer

Overexploited aquifer EXAMPLE

Answer 19

• Largest agricultural region in China, has fertile soil but few rivers so groundwater is used instead for irrigation
• Growing demand for irrigation water & growing population has caused the water table to lower by around one metre per year

Question 20

What measures are introduced to manage the north china plain ?

Overexploited aquifer EXAMPLE

Answer 20

• Low pressure irrigation pipes to reduce leaks
• Proposal of growth of crops which require less water to grow
• Consumers charged for volume of water they use in order to encourage water conservation

Question 21

What are 3 ways water availability affects life ?

Exploitation of new sources of water

Answer 21

• quality of life
• which industries can be developed
• where people can live

Question 22

What are 5 methods of using water, thats not an aquifer ?

Exploitation of new sources of water

Answer 22

• rivers
• resevoirs
• rainwater
• estuary barrage
• seawater

Question 23

What is an estuary barrage ?

Exploitation of new sources of water

Answer 23

A freshwater reservoir created by building a dam across an estuary where a river enters the sea

Question 24

How is rainwater collection performed ?

Exploitation of new sources of water

Answer 24

• header tank connected to roof to collect
• if this ovefflows it goes to an underground tank
• if this overflows then it recharges aquifers

Question 25

4 factors affecting the usefulness of a river for water exploitation

Exploitation of new sources of water

Answer 25

• total annual flow
• flow fluctuations
• level of natural contaminants
• pollution from humans

Question 26

1 Positive and 2 negatives of an estuary barrage

Exploitation of new sources of water

Answer 26

+ fewer land use conflicts
- change important intertidal habits
- can be polluted by human activity

Question 27

What is artificial recharge of aquifers ?

Sustainable management of water

Answer 27

Where surplus water is unable to infiltrate so it is pumped elsewhere (eg. underground lagoons)

Question 28

What does an interbasin transfer do ?

Sustainable management of water

Answer 28

Canal & pipe systems transfer water from areas of surplus to areas of deficit

Question 29

What are 3 reasons we would use afforestation to create sustainable water sources ?

Sustainable management of water

Answer 29

• trees reduce soil erosion + reduce surface runoff
• Reudce fluctuations in river flow
• Reduces flooding after heavy rain + maintains levels during low rainfall

Question 30

what are 3 ways to lower the volume of water usage ?

Water conservation

Answer 30

• low water appliances
• low volume irrigation
• Xeriscaping

Question 31

what is Xeriscaping ?

Water conservation

Answer 31

management of gardens, parks & open spaces by planting them with plants that require less water

Question 32

what is grey water ?

Water conservation

Answer 32

retaining water that has been used but is still quite clean and can be reused for other purposes (water used for bath or showers)

Question 33

what does a water metre do and why would we use it to help water conservation ?

Water conservation

Answer 33

Water metres match volume of water used to the price charged, encourages people to use less

Question 34

What is the order of the water treatment process ?

Water Treatment

Answer 34

sedimentation → screens → Aeration → Flocculation/ coagulation & clarification → Filltration → activation of carbon filters → sterilisation → pH control → flouridation → ion exchange → reverse osmosis → distillation