Lesson 6-What are the factors affecting change in the water cycle?

Question 1

What are the different changes in the water cycle?

Answer 1

1) Changes in flows and transfers Balance of precipitation and evaporation
2) Global factors such as climate change affecting the amount and location of the water stored
3)Local factors including changes in how water is moved from one place to another

Question 2

Changes in the water cycle-Global factors such as climate change affecting the amount and location of the water stored

Answer 2

The size or magnitude of different stores of water EG water stored in ice, or in ground water.

Question 3

Changes in the water cycle- Local factors including changes in how water is moved from one place to another

Answer 3

Changes in water transfers such as how much is moved by rivers, surface run off, through flow etc. And the reasons behind these.

Question 4

What are natural changes within the water cycle?

Answer 4

• Natural climate change
• Extreme climatic events, such as drought, impact the water cycle by reducing the amount availble within the system
• Ecosystem changes like plant succession may alter the dominant vegetation in an area which can alter interception rates
• Seasonal changes- wet and dry seasons change the availability of water within a system

Question 5

Human changes to the water cycle?

Answer 5

• Climate change
• Farming practices
• Deforestation
• Land use change
• Water abstraction

Question 6

Precipitation

Answer 6

Transfer of water from the atmosphere to the Earths surface in the form of rain, hail, snow and dew

Question 7

Interception

Answer 7

Precipitation that is caught and stored (temporarily) on its way to the surface by leaves, plants, grasses and tree

Question 8

Overland/Surface Flow

Answer 8

This is when water flows over the land’s surface

Question 9

Infiltration

Answer 9

Where the water enters small openings and pores in the ground from the surface

Question 10

Throughflow

Answer 10

Throughflowis the lateral (sideways) movement of water through the upper soil

Question 11

Percolation

Answer 11

Where water flows down through the soil layers and underlying rock

Question 12

Groundwater Flow

Answer 12

Also calledbaseflowand iswater that has infiltrated and percolated into the bedrock and below the water table

Question 13

Evapotranspiration

Answer 13

Combination of evaporation and plant transpiration

Question 14

Condensation

Answer 14

Transfer of water from a gaseous (vapour) state to a liquid state as in cloud formation

Question 15

Sublimation

Answer 15

This is when water changes from a solid (ice) to a gas (vapour)withoutpassing through a liquid state or vice versa

Question 16

Trunk and Stem Flow

Answer 16

This is the flow of water down the stems of plants or trunks of trees

Question 17

Zone of saturation

Answer 17

The height of the water table will vary according to the season. Where there is permanent saturation, this is called thephreatic zone

Question 18

Change 1- Changes in flows and transfers Balance of precipitation and evaporation

-seasonal variations

Answer 18

• Seasons change the balance of precipitation and evaporation
• We get more pronounced seasons the higher the latitude.
• This is due to the tilt of the earth on its axis meaning that higher latitudes receive greater variation in solar radiation throughout the year.
• This means they get bigger seasons than equatorial areas.

Question 19

Change 1- Changes in flows and transfers Balance of precipitation and evaporation

-how do precipitation and infiltration change throughout the year

Answer 19

• Precipitation- Total rainfall is less in the summer but may be more prone to flash floods. In winter there are greater quantities of rainfall
• Evaporation- Lower temps reduce the rate in winter but in summer is opposite
• Soil moisture- In winter there are more saturated soils which lead to overland flow (loss of water). In summer, Soils may dry and reduce the availability of water but rain may infiltrate quickly

-Vegetation- Vegetation dies back, reducing interception and transpiration in winter. Vegetatiuon grows increasing these rates in summer

• River channel flow- Higher discharge rates are usual with winter storms in winter. Lower discharge rates as levels of precipitation drop

Question 20

Change 1- Changes in flows and transfers Balance of precipitation and evaporation

• Extreme weather events

Answer 20

• Drought – decrease precipitation, initial increase evaporation then decrease when all water evaporated. Decrease stores of water. E.g California 2012-2016
• Storm – increase precipitation, increase surface run off, increase water stored

Question 21

Change 1- Changes in flows and transfers Balance of precipitation and evaporation

-How did the Californian drought affect the water cycle?

Answer 21

• Less water is stored in rivers and lakes
• Vegetation dies or is destroyed in fires
• Ground water flow decreases
• It is hotter and air is dryer

Question 22

Change 1- Changes in flows and transfers Balance of precipitation and evaporation

-Californian effects- Vegetation dies or destroyed in fires

Answer 22

• less interception during rainfall
  more surface run off
• Vegetation dying causes soil degradation and erosion
• Dry ground = impermeable meaning less infiltration
• More surface run off.

Question 23

Change 1- Changes in flows and transfers Balance of precipitation and evaporation

-Calafornian effects- Ground water flow decreases

Answer 23

• Less water infiltrating, less water percolating
• less water reaching ground water to recharge underground stores.
• Ground water is a longer term store/process it takes a longer time to be impacted and is less impacted by short term events.
• In droughts ground water is often abstracted for human use so therefore levels in wells and aquifers fall. This can take a long time to recharge.

Question 24

Change 1- Changes in flows and transfers Balance of precipitation and evaporation

-Californian effects- It is hotter and air is dryer

Answer 24

• Hotter air can store more water before condensation occurs.
• However as there is a lack of water the total water stored in the air and atmosphere at a local scale decreases.
• When air is dry we get increased rates of evapotranspiration at first.

Question 25

Change 2-Global factors such as climate change affacting the amount and location of water stored

-Global factor 1, Climate change

Answer 25

• Changes in theearthsorbitknown asMilankovitchcycles havechangedclimate over timemeaning we havehadglacial and interglacialperiods.
• During the last Ice Age(approx. 18,000yrsago),roughly a third of Earth’ssurfacewas covered in icesheets and glaciers

Impact on stores of water:
- This increased the magnitude (size) of the cryosphere’s stores

• But, it lowered the hydrosphere’s store (no flow of liquid water) and sea levels were over 100 m lower than present date

Question 26

Change 2-Global factors such as climate change affacting the amount and location of water stored
-Global factor 2, Clouds and Precipitation

Answer 26

• Insolation at the Equator causes high evaporation, leading to cloud formation and heavy rainfall in the low-pressure zone called the Inter-Tropical Convergence Zone (ITCZ), which shifts with the Sun’s movement, creating seasonal variations in water patterns.

Impact on stores of water:

• Precipitation amounts vary with higher rates in summernorth of the equator and higher rates in winter south ofthe equator​
• Low-pressure rain/monsoon conditions with themovement​
• This shows temporal and spatial changes in stores andtransfers on a global basis

Question 27

Change 2-Global factors such as climate change affacting the amount and location of water stored

-Global change 3, Cryospheric Change

Answer 27

If ice melts:
-The total melting of the ice sheets could result in a 60 m sea level rise, which is a lot of stored water

• Melting of the ice sheets adds water to the hydrosphere store of the oceans
• Warmer ocean waters mean that Ice sheets are destabilised (start to melt), which triggers ice calving (icebergs breaking off the ice sheet), these icebergs melt; adding to the hydrosphere store and rising sea levels

If ice forms:
-Sea levels drop , there is more white causing albedo effect, snowball earth means that light is reflected and earth isnt heated

Question 28

Change 3- Local factors including changes in how water is moved from one place to another
-Local factor 1- Inputs and outputs

Answer 28

-Inputs are Evaporation due to the energy from the sun and also Precipitation

• Transfers include throughflow, infiltration and Ground water flow

-Outputs being evaporation, runoff, percolation into ground water

Question 29

Change 3- Local factors including changes in how water is moved from one place to another
- Local factor 2- Urbanisation

Answer 29

• Reduction in green spaces – reduced evapotranspiration, stemflow.
• Increase inimpermeable surfaces increased run off and increased river channel storage decrease infiltration.
• Decreased ground water storage.

Question 30

Change 3- Local factors including changes in how water is moved from one place to another
- Local factor 2-SUDS Manor Fields

Answer 30

• Through use of swales and retention basins, ground water flow and storage can be increased. This will increase lag time in a storm event, and will help to reduce the risk of flooding in Sheffield centre.
• Manor Fields cannot be a standalone project.

-The rewinding of parks across Sheffield is needed to address flood risk. With this in mind, there needs to be a series of parks and SUDS across Sheffield that can together reduce flood risk.

Question 31

Change 3- Local factors including changes in how water is moved from one place to another
- Local factor 3- Deforestation and afforestation

Answer 31

Deforestation:

• Reduces interception – more water reaches the ground
• Reduces infiltration – water reaches the ground too quickly to all be infiltrated
• Affects surface stores as soil is eroded and removed as tree roots hold soil together increasing infiltration.
• Less evapotranspiration as less leaves to intercept water.

Aforestation:

• Afforestation is the opposite of deforestation it is planning trees.

Question 32

Change 3- Local factors including changes in how water is moved from one place to another
- Local factor 4- Farming changes

Answer 32

• Decreased soil storage - ditches drain the land and increase water flow away from the land
• Increased interception/evaporation - the interception by vegetation can prevent as much as 40% of precipitation from reaching the surface
• Decreased ground water storage - over-abstraction of groundwater for irrigation removes stores of water
• In parts of the Middle East, water is being abstracted from underground aquifers that were formed thousands of years ago. E. Pivot irrigation in Saudi Arabia

Question 33

Change 3- Local factors including changes in how water is moved from one place to another
* Local factor 5- Industrialisation

Answer 33

• = Industrialisation
• Burning of fossil fuels generates CO2 in the atmosphere enhancing the greenhouse effect and global warming
• Changes in Precipitation: Amount and rate / intensitycan changeaffecting magnitude of stores
• Acid rain increase:Industrial output can produce acid rain, which destroys vegetation reducing interception, stem flow and transpiration and increasing surface run offand affecting water stores