The hydrosphere

Question 1

What do human activities do to the hydrosphere?

Answer 1

They can alter the rate of processes in the hydrological cycle which can lead to changes in the residence time and quantities in reservoirs of water.

Question 2

How do you calculate residence time?

Answer 2

vol of water in reservoir/ mean transfer rate

Question 3

Why is the global demand for water increasing?

Answer 3

Increased population
Increase in per-capita with increased affluence so more piped water, water appliances
Increased irrigation of farmland for growing populations
Industrialisation e.g. chemical and steel

Question 4

What are the inputs for the hydrological cycle?

Answer 4

Precipitation

Question 5

What are the outputs of the hydrological cycle?

Answer 5

Evaporation
Transpiration

Question 6

What are the ways water moves to different reservoirs/ transfer processes?

Answer 6

Percolation
Ground water flow to the ocean

Question 7

What drives the hydrological cycle?

Answer 7

Solar energy-evaporation etc
Gravitational potential energy- water moves through rocks to the ocean

Question 8

How do you convert m3 to km3?

Answer 8

Divide by 1000

Question 9

What is the residence time?

Answer 9

The average time a water molecule will spend in a reservoir

Question 10

How does deforestation affect the hydrological cycle?

Answer 10

Vegetation intercepts rainfall which may evaporate before reaching the ground.
Trees return alot of water from the soil to atmosphere by transpiration.

Question 11

How does agriculture affect the hydrological cycle?

Answer 11

Soil being compacted will reduce infiltration and increases runoff
Crop irrigation may increase evaporation
Loss of soil biota will reduce infiltration, increases run off and reduces water retention.

Question 12

How does urban development affect the hydrological cycle?

Answer 12

Replacing impermeable surfaces like concrete with gravel/sand will increase infiltration and reduce runoff.

Question 13

What water sources have been exploited unsustainably?

Answer 13

Aquifers and reservoirs

Question 14

What was the main reason for the aral sea drying up?

Answer 14

Irrigation of cotton and rice crops using water from rivers that fed into the aral sea.
Pollution from pesticides and fertilisers

Question 15

What is an aquifer?

Answer 15

An underground layer of water bearing rock

Question 16

What are the features of rock suitable as an aquifer?

Answer 16

Good porosity so alot of space to hold water, limestone/chalk
Rock above should be permeable but rock underneath should not be, granite or clay.

Question 17

How are aquifers recharged?

Answer 17

By rain, they are usually in dynamic equlibrium.

Question 18

When does an aquifer become over exploited?

Answer 18

When human abstraction is greater than recharge.

Question 19

What water is usually in ancient aquifers?

Answer 19

Saline water, so it causes soil salination, osmotic dehydration and then crop death if used for irrigation

Question 20

What are the ecological impacts of over exploiting aquifers?

Answer 20

Plants die
Wetland habitats will decrease killing aquatic plants and animals
Affects inter-species relationships and food webs

Question 21

What is salt water incursion?

Answer 21

When aquifers are exploited their water table lowers, it could become lower than the sea level causing seawater to flow in to replace what has been lost.
This makes the aquifer saline, water cannot be used in irrigation

Question 21

What is subsidence?

Answer 21

Over exploitation of aquifers means less water is held in porous rock, the rocks therefore have less support and will become compacted by the weight of material above.

Question 22

How can you measure aquifer depletion?

Answer 22

Checking the water table
Grace satellite/ gravity recovery and climate experiment: the orbit of this satellite is affected by gravity which is influenced by the mass of water in aquifers

Question 23

Describe the ogollala aquifer and what the problems are

Answer 23

A high plains aquifer
Agriculture relies on this aquifer however it is being over exploited/ abstraction is greater than recharge.
The water in this aquifer is paleowater, so it was last recharged years ago

Question 24

What are some methods china has implemented to conserve their water?

Answer 24

Growing crops with low water needs low pressure irrigation pipes to reduce leaks afforestation charging for overconsumption of water

Question 25

What are the environmental effects of reservoirs?

Answer 25

Construction of a dam/reservoir changes habitats, but creates wetlands. Dam will act as a wildlife barrier to migrating wildlife, prevents recolonisation. Sedimentation, no nutrients bought downstream Changes the microclimate: large body of water and high SHC stops temp fluctuations. Greater evaporation so more precipitation.

Question 26

How are river flow regimes used?

Answer 26

Used to regulate flow. When flow is high/ in surplus water is held back to stop flooding. When flow is low water is released

Question 27

What are the features of a good reservoir?

Answer 27

Topography- narrow exit with a large deep basin Geology- underneath rock must be impermeable, but also strong Catchment area- area of high rainfall, or an area with a river that carries water to the reservoir Low pollution risk

Question 28

Why should a reservoir not be near a forest?

Answer 28

Dead organisms from the forest will decay in the water anaerobically releasing methane

Question 29

What infrastructure has to be taken into account when building a reservoir?

Answer 29

Building the dam Treatment of water Pathways for machinery Pipes to transport water Workers

Question 30

What is an estuary barrage?

Answer 30

A freshwater reservoir created by making a dam across an estuary

Question 31

What are the problems with estuary barrages?

Answer 31

They change inter-tidal relationships Create a problem for shipping Water stored may be polluted

Question 32

Why is seawater not used?

Answer 32

The desalination process is very expensive and energy intensive

Question 33

What is artificial recharge?

Answer 33

Maintaining aquifers by using surplus water to recharge them. Water is pumped into the aquifer or it is put into a lagoon where is can infiltrate

Question 34

What are river-regulation reservoirs?

Answer 34

Used to regulate river flow In low rainfall water can be released and in high rainfall water can be held back to reduce flooding

Question 35

What is inter-basin transfer?

Answer 35

A pipe system to transfer water from areas of shortage

Question 36

What are some methods used to conserve water?

Answer 36

Low water appliances Xeriscaping Drip irrigation Recycling water/grey water being used to water crops Water meters Maintaining old pipes so no leaks Controlling pollution so less water needs to be treated.

Question 37

What is potable water?

Answer 37

Drinking water, has no has no pathogens

Question 38

What does irrigation water have to be?

Answer 38

Not saline Low toxins Low sediments

Question 39

What is the water treatment process in order?

Answer 39

Sedimentation Screening Aeration Flocculation Filtration Activated carbon filter Sterilisation pH fluoridation ion exchange

Question 40

What is screening?

Answer 40

Using mesh screens or metal bars to trap and remove large objects like plastic

Question 41

What is aeration?

Answer 41

Using water sprays to aerate water and ensure a high dissolved O2 conc. Makes metals become insoluble

Question 42

What is flocculation?

Answer 42

Clay particles will not settle in sedimentation due to electrostatic charges causing them to repel. The charges can be neutralised by adding alum/ aluminium sulfate.

Question 43

What is filtration?

Answer 43

The removal of the remaining materials by letting it flow through sand/gravel

Question 44

What is activated carbon filter?

Answer 44

Removes organic chemicals like pesticides by adsorption onto activated carbon

Question 45

What is sterilisation?

Answer 45

Using chlorine, UV or ozone to kill pathogens

Question 46

What is pH in the water treatment processs?

Answer 46

Using crushed lime to make conditions more alkaline because when using chlorine water will become acidic.

Question 47

What is fluoridation?

Answer 47

Adding fluorides to improve dental health

Question 48

What is ion exchange?

Answer 48

Toxins, like lead, iron and calcium removed. They adsorb onto polymer beads this produces 'soft' water bc no calcium

Question 49

What is reverse osmosis?

Answer 49

Sea water being filtered at high pressure through partially permeable membranes V spenny process so not used often

Question 50

What is distillation?

Answer 50

Water is boiled to produce steam, the steam is condensed to water vapour and collected