Water

Question 1

closed system

Answer 1

the amount of water is kept the same and just circulated continuously

Question 2

inputs

Answer 2

the movement of matter or energy into a system for example precipitation from the atmosphere into the ground or the sea

Question 3

outputs

Answer 3

the movement of matter or energy out of a system so for example evaporation from the land or sea into the atmosphere

Question 4

stores

Answer 4

where water is stored
water is stored for long periods of time in oceans (3600 years) and as groundwater (up to 10000 years)

Question 5

flows

Answer 5

the amount of matter or energy transferred from one place to another

Question 6

what does solar energy cause?

Answer 6

heat energy from the sun causes changed in the state of water and drives some of the processes such as evaporation

Question 7

gravitational potential energy

Answer 7

the mass of the earth exerts a pull ok water causing water to fall as precipitation and refuses to flow downhill back to the ocean (the main store)

Question 8

diagram of the hydrological cycle

Answer 8

Question 9

what are some examples of water stores and what are their residence times?

Answer 9

Question 10

why are some stores considered to be non-renewable?

Answer 10

because they are not replaced in a short period of time
for example:
– Fossil water was stored underground in rocks are very long time ago when the climb of an area was much wetter

Question 11

describe the annual global fluxes diagram

Answer 11

Question 12

what is the global water budget?

Answer 12

the annual balance between the fluxes sand size of water stores is known as the global water budget

Question 13

why is water generally considered to be a renewable resource?

Answer 13

Because there is a constant circulation and replenishment of stores without any losses from the planet

Question 14

how can the availability of water change throughout a year?

Answer 14

if there is a dry season or the climate in summer is hotter than normal then transpiration and evaporation rates may be higher

Question 15

what is transpiration

Answer 15

the evaporation or loss of water from a plant mainly through its stomata

Question 16

why do people need water

Answer 16

it is essential to lose and also used for farming, industry and cooling machinery

Question 17

what is orographic rainfall

Answer 17

– Relief rainfall
– cause when humid air is forced to rise over mountains
– when the air calls higher altitude, moisture condenses forming clouds and droplets of water which then fall due to gravity
– most rain falls on the slopes facing the direction direction and top of the mountains with dry air on the other side (Lee) so less rainfalls (rain shadow)

Question 18

what is frontal rainfall

Answer 18

– Course when humid air is forced to rise at a warm front or cold front line
– usually as part of a depression (low pressure system)
– again, the air calls, condensation takes place, clouds of water droplets form which has followed by rain

Question 19

what is conventional rainfall?

Answer 19

– Cause when the ground and lower atmosphere are heated by the Sun causing rising air.
– humidity in the air condenses when it cools at high altitudes, forms towering culo nimbus clouds, often followed by intense heavy rainfall (thunderstorms)

Question 20

what is interception?

Answer 20

when a layer of vegetation covers the ground and do intercepts rainfall before it can reach the ground

Question 21

what is infiltration?

Answer 21

the movement of water downwards through spaces in the soil; this continues until capacity is reached and the soil becomes saturated

Question 22

what is throughflow?

Answer 22

the movement of water downslope through the soil towards base level (river, lake or sea)

Question 23

what is surface run off?

Answer 23

rain falling onto the ground may flow over the surface when it is so intense that there is no time for it to infiltrate

Question 24

what is saturated overland flow?

Answer 24

if all soil spaces are full of water, then any further rain infiltrate and so will run off the surfacr

Question 25

what is percolation?

Answer 25

the movement of water downwards through porous or permeable rocks?

Question 26

what is groundwater flow?

Answer 26

the downwards and sideways movement of water in rock layers under the influence of gravity and rock structure

Question 27

what are the 3 outputs?

Answer 27

evaporation
transpiration
channel flow

Question 28

what is channel flow

Answer 28

run-off moves to the lowest points in a landscape where it collects to form a linear body of water flowing over the ground. The larger the amount of water, the larger the discharge.

Question 29

what are the influences of physical factors on the hydrological cycle?

Answer 29

Question 30

what human factors can disrupt the hydrological cycle?

Answer 30

deforestation
land use change
reservoir creation
abstracting water

Question 31

how does deforestation effect the hydrological cycle?

Answer 31

removal of tree cover reduces interception and evapotranspiration, increasing surface run-off, soil erosion, and flooding during intense rainfall.

Question 32

how does land use change effect the hydrological cycle?

Answer 32

natural vegetation absorbs more water than urbanised permeable surfaces which increased run-off and flow creating higher discharges and more flooding

Question 33

how does reservoir creation change the effects of the hydrological cycle?

Answer 33

damming a river prevents channel flow, reducing discharge, downstream, and creating an evaporation source.

Question 34

how does abstracting water change the hydrological cycle?

Answer 34

people use water for several purposes and sometimes this is taken from the surface all the ground faster than it is replaced meaning natural ways for water to leave an underground aquifer for example like rivers or springs will be affected

Question 35

what is a water budget?

Answer 35

an account of the water stored in a system, such as a watershed, and the movement of water in and out of that system, annually

Question 36

what is the water budget equation?

Answer 36

precipitation = channel discharge + evaporation +/- storage
P = Q + E +/- S

Question 37

what does the water budget equation do?

Answer 37

– Allows a calculation of water supply during a year and identification of time periods when there may not be enough to meet natural and human needs
– When precipitation is greater than channel discharge and vapo transpiration there is a positive water balance when precipitation is less than channel discharge and evapotranspiration, there is a negative one.

Question 38

what is soil moisture and why is it important?

Answer 38

– soil moisture is the amount of water in the soil and it is important for successful plant growth.
– in an ecosystem it is important to have enough soil moisture so that plants support other trophic levels (feeding groups.
– it is most important that soil moisture is high during growth season (spring and summer)

Question 39

how does land use affect patterns within river catchment areas?

Answer 39

– Land use affects the movement of water after precipitation, such as interception and absorption by forests or the impermeable surfaces of urbanisation.
– land use zoning can reduce risk by controlling building on flood planes.
Planners are also involved in decision-making about flood prevention and protection

Question 40

what are the factors effecting river regimes?

Answer 40

Question 41

what are the factors effecting storm hydrographs?

Answer 41

Question 42

what is drought?

Answer 42

drought is classified by a number of factors:
- weather conditions may remain dry for a longer period than normal
- farmers may experience a decline in soil moisture levels
- water levels in rivers and reservoirs fall
- human demand for water is greater than supply

drought is a slow onset hazard affecting 10% of earths land area and 18% of the population

Question 43

what are some short term causes of drought?

Answer 43

blocking anticyclones: the polar front jet stream may move up (north) meaning subtropical high pressure air can move into the space it has vacated. In the summer of 2018 this caused widespread drought across the UK.

reduced soil moisture levels: there may not be enough precipitation to soak into soils because plants use it quickly or there is higher evaporation

Question 44

what are some medium term causes of drought?

Answer 44

El Niño Southern Oscillation (ENSO): ENSO cycles occur in the pacific ocean every 7 year roughly. During El Niño warm water moves closer to the Americas reducing rainfall in the western pacific. During La Niña warm water moves to the extreme west of the tropical pacific, reducing rainfall in western parts of the americas. These cycles are known to have global effects such as La Niña events causing drought in East Africa.

Hydrological: Reduced amounts of water in rivers or the ground may occur if precipitation is reduced in mountainous areas over several years, especially reducing the amount of snow melt.

Question 45

What are some long term causes of drought?

Answer 45

Global atmospheric circulation: descending air between the hadley and ferrel cells and between the polar cells creates hot and cold deserts respectively, also affecting the areas around them where droughts are common

Climate change: evidence suggests that higher temperatures are changing atmosphere systems. Subtropical high pressure areas are getting stronger, which stops the seasonal movement of ICTZ (which causes droughts). Rainfall events have become more intense rather than spread out over time. Higher sea temps have changed evaporation and wind patterns which may cause rain bearing winds to fail and have changed ocean currents; where cold currents become stronger evaporation is reduced causing drier conditions

Question 46

how do you interpret synoptic charts?

Answer 46

• dark lines with triangles of half circles are fronts, pointing in the direction of movement
• triangle = cold
• semi circle = warm
• fainter lines are isobars with a number indicating the pressure in MB
• H = high pressure centres (anticyclones)
• L = low pressure (depressions/extra-tropical cyclones)

Question 47

how does human activity lead to drought risk? (what things do humans do that cause droughts?)

Answer 47

over-abstraction of surface water: taking too much water from rivers and lakes and not replenishing it with precipitation
over-abstraction of groundwater: taking too much water out of aquifer stores lowering the water table and making wells dry up
deforestation: reduces interception, absorption and evapotranspiration so that water is lost from local areas, making them drier and more susceptible to drought
climate change: emissions of greenhouse gases are accelerating global warming which is changing precipitation patterns

Question 48

what are wetlands and how are they vulnerable to drought?

Answer 48

wetlands are a type of ecosystem that is largely flooded. they have adapted to this so conditions changing will make the ecosystem vulnerable. their capacity to act as a natural filter and above floodwaters will be reduced after repeated droughts.

other processes like the oxidation of soils will release carbon into the atmosphere and nutrients or pollutants may become dangerously concentrated. some species like birds will leave the area and plants may be lost.

Question 49

what are forests and how are they vulnerable to droughts?

Answer 49

forests have an important role in the hydrological cycle as well as other natural cycles such as carbon
trees in forests are often large and so require a large amount of water, especially fast growing species like pine
drought slows growth and causes stress, potentially causing the trees to lose leaves and be unable to photosynthesis, this can take as many as 4 years to recover from
droughts also weaken trees so they are more vulnerable to insects such as pine beetles and diseases
trees dying off can also harm food chains

Question 50

what’s a textbook definition of flooding?

Answer 50

In areas experiencing a lot of precipitation, flooding may be a possibility. It may be fast onset (flash floods) or slower onset. The most common form of flooding occurs when a river reaches and then exceeds bank full discharge; additional water cannot be contained within the channel and so spills over onto the surrounding land (flood plain).

Question 51

what are some meteorological causes of flooding?

Answer 51

• intense storms
• heavy rainfall
• snowmelt
• prolonged rainfall
• monsoon rains

Question 52

why do intense storms cause flooding?

Answer 52

they bring a lot of rainfall in a short period, which moves quickly meaning it’s unable to soak into the ground causing it to flow more quickly into channels leading to them overflowing their banks. If the water runs over baked grounds it can lead to flash floods.

Question 53

why does snowmelt cause floods?

Answer 53

snow can accumulate to a considerable depth and the climate quickly warming up in the spring can cause it to start melting quite rapidly.
frozen ground underneath the snow and steep slopes can cause the water to flow quickly.

Question 54

why does heavy rainfall cause flooding?

Answer 54

too much rainfall can prevent throughflow or groundwater flow from taking place so the excess water runs off the surface and into rivers

Question 55

why does prolonged rainfall cause flooding?

Answer 55

persistent rainfall is often the result of several low pressure systems passing over an area causing a sequence of frontal rainfall. first the soil is saturated so that later rainfall cannot infiltrated. this causes run off to increase and quickly enter river channels causing floods.

Question 56

why do monsoons cause flooding?

Answer 56

subtropical areas often have wet or monsoon seasons, especially areas where there’s land between a mountain and a warm ocean. Monsoon seasons are characterised by torrential rainfall which falls onto hard dry ground. This causes increased surface run off and then saturated ground meaning water flows faster into rivers, increasing levels until they flood.

Question 57

what are the human influences on flooding?

Answer 57

land use change
floodplain use
hard engineering

Question 58

why is land use change a human cause of flooding?

Answer 58

removal of natural vegetation and its replacement with impermeable surfaces causes changes in hydrological processes.
run off is increased from roofs or farmed land (impermeable surfaces).
soil erosion increases adding sediment to rivers channels, changing their shape and reducing capacity so that they flood with a lower discharge.

Question 59

why does hard engineering increase flood risk?

Answer 59

bridges narrow river channels, reducing capacity and causing higher water levels upstream or suddenly downstream if a bridge collapses
artificial levees increase channel capacity but transfer more water downstream increasing flood risk, also, if they break they cause flash floods over a wide area
channelisation (straight concrete channels) transfer water more quickly downstream, increasing risk.

Question 60

why does floodplain use cause increased flood risk?

Answer 60

floodplains are often drained for construction causing the land to shrink as it dries out, taking it below normal river levels and causing it to flood more easily

Question 61

what are the environmental impacts of flooding?

Answer 61

• ecosystems: small floods can be beneficial as they help to replenish ecosystems but intense floods increase soil and river erosion and cause pollutants to get into water ways
• soils: become waterlogged on level ground or scoured away on slopes by increased surface flow. flood events reduce the microbial biomass in soil but in the long term more nutrient rich soils are provided.