The Hydrosphere

Question 1

Global demand for water

Answer 1

Increased population
Increase per capita use
Increased irrigation of farmland-agriculture usually relies on natural water sources but now have to use water pumped from aquifers etc- it uses more water that all other human uses combined

Question 2

Environmental impacts of reservoirs

Answer 2

Habitat change
Wildlife Barriers for species that migrate along the river
Sedimentation - sediments will settle in the reservoir rather than building up river banks and counteract erosion

Question 3

Features of aquifers

Answer 3

Porosity: measure of proportion of a rocks volume that is paces and could hold water- chalk and limestone are good at this
Permeability:measure of easy water can flow in the aquifer
Geological structures:rock below aquifer must be impermeable so the water can’t escape , clay and granite are good at this

Question 4

Water conservation

Answer 4

Low water appliances -washing machines
Xerscaping-management of gardens and parks, planting them with species that are adapted to dry conditions so less water is needed to water them
Low volume irrigation-drip irrigration delivers water directly leading to lower evaporation loss than overhead soray

Question 5

Water treatment process

Answer 5

Sedimentation :
Suspended solids settle

Screens:
Metal meshes remove vegetation and litter

Aeration:
Bubbles of air aerate the water so there is a high dissolved O2 conc.
Dissolved metals are removed by aeration and they become insoluble

Flocculations/coagulation:
Flocculents added(aluminium sulfate), they mix with the water and pass into the clarifier tank where the particles settle

Filtration
Filtered used to removed remaining suspended soils

Carbon filters :
Actived carbon filters are used to remove organic chemicals such as pesticides

Sterilisation :
Chlorine and ozone used to sterilise and kill pathogens, chlorine is most common

PH control:
Chlorine can make it to acidic so add crushed lime

Fluoridation:
Fluorides added to improve dental health

Ion exchange:
Toxic ions removed using ion exchange resins

Reverse osmosis:
Is used to remove the salt out of sea water and is cheaper than desalination