The water cycle

Question 1

What are systems made up of

Answer 1

Stores, Flows, boundaries, inputs and outputs

Question 2

Define input

Answer 2

When matter or energy is added into the system

Question 3

Define output

Answer 3

When matter or energy leaves the system

Question 4

Define stores

Answer 4

Where matter or energy builds up

Question 5

Define Flows/Transfers

Answer 5

When matter or energy moves from one store to another.

Question 6

Define boundaries

Answer 6

The limits of the system.

Question 7

What is an example of a system within the water cycle and why?

Answer 7

Drainage basin system

Water enters as rain (input)

The system’s watershed is the boundary

Some water is stored in soil and vegetation

Water then travels from the drainage basin to the river then flows down the river.

Water then leaves the system where the river meets the sea.

Question 8

What is an open system

Answer 8

When both energy and matter can enter and leave the system.

Question 9

What is a closed system

Answer 9

-Matter can’t enter or leave a closed system - it cycles between stores.

Question 10

What are Earth’s subsystems

Answer 10

Cryosphere

Lithosphere

Hydrosphere

Atmosphere

Biosphere

Question 11

What is the cryosphere

Answer 11

The cryosphere includes all of the parts of the Earth system where its cold enough for water to freeze. e.g. glacial landscapes

Question 12

What is the lithosphere

Answer 12

The lithosphere is the outermost part of the Earth. It includes the crust and the upper parts of the mantle

Question 13

What is the biosphere

Answer 13

The biosphere is the part of the Earth’s systems where living things are found. It includes all the living parts of the Earth.

Question 14

What is the hydrosphere

Answer 14

The hydrosphere includes all of the water on Earth.

It may be in liquid form, solid state or gas.

It can also be saline or fresh.

Question 15

What is the atmosphere

Answer 15

The atmosphere is the layer of gas between the Earth’s surface and space, held in place by gravity.

Question 16

How is the Earth an example of a cascading system?

Answer 16

All the subsystems are interlinked, the output of a system is the input of another, and so on.

Question 17

What is positive feedback

Answer 17

When the effects of an action are amplified by subsequent knock on effects that occur, moving the system further from its previous state

Question 18

What is negative feedback

Answer 18

When the effects of an action are nullified by subsequent knock on effects that occur, moving the system closer to its previous state.

Question 20

How much of the Earth’s total water is stored in Oceans?

Answer 20

96.5%

Question 21

Global distribution of Earth’s fresh water

Answer 21

Glaciers and ice caps - 68.7%

Ground Water - 30.1%

Fresh waters - 2.5%

Question 22

Global distribution of Earth’s surface water and other fresh water

Answer 22

Ground ice and permafrost - 69%

Rivers and Lakes - 21.4%

Soil Moisture - 3.8%

Question 23

Residence time of Water in shallow groundwater

Answer 23

100-200 years

Question 24

Residence time of water in deep groundwater

Answer 24

10,000 + years

Question 25

Residence time of water in glaciers

Answer 25

20-100,000+ years

Question 26

Residence time of Water in Lakes

Answer 26

2 weeks to 100 years

Question 27

Residence time of water in seasonal snow cover

Answer 27

2 to 6 months

Question 28

Residence time of water in Soil water

Answer 28

1 to 2 months

Question 29

Residence time of water in rivers

Answer 29

2 to 6 months

Question 30

Define evaporation

Answer 30

The process of a substance in a liquid state changing to a gaseous state due to an increase in temperature/pressure.

Question 31

Define condensation

Answer 31

The conversion of a vapour or gas to a liquid.

Question 32

Define convectional rainfall

Answer 32

When the land warms up, it heats the air above it. This causes the air to expand and rise. As the air rises it cools and condenses. If this process continues then rain will fall.

Question 33

Define sublimation

Answer 33

The transition of a substances directly from the solid to the gas phase without passing through the intermediate liquid phase.

Question 34

Define transpiration

Answer 34

The process by which moisture is carried through plants from roots to small pores on the underside of leaves It then changes to vapour and is then released into the atmosphere.

Question 35

Define precipitation

Answer 35

Transfer of water from the atmosphere to the ground. It can take the form of rain, snow, hail, dew.

Question 36

Define interception

Answer 36

Water intercepted and stored on the leaves of plants

Question 37

Define overland flow

Answer 37

Transfer of water over the land surface

Question 38

Define infiltration

Answer 38

Transfer of water from the ground surface into soil Here it then percolates into underlying rocks.

Question 39

Define through flow

Answer 39

Water flowing through soil towards a river channel

Question 40

Define percolation

Answer 40

Water soaking into rocks

Question 41

Define Groundwater Flow

Answer 41

Transfer of water very slowly through rocks.

Question 42

What is an aquifer?

Answer 42

An aquifer is a body of permeable rock or unconsolidated material such as sand or slit that can store and transmit groundwater.

Question 43

key points of an aquifer

Answer 43

Acts like an underground reservoir Water can be extracted using wells or springs

Question 44

Where do aquifers most commonly form

Answer 44

Aquifers most commonly form in areas where the geology allows water to be stored and transmitted easily (permeable rocks or sediments).

Question 45

The soil water budget?

Answer 45

The soil water budget is a model that shows the balance between water inputs, outputs, and storage in the soil over time.

Question 46

What is the upper layer of saturated rock in an aquifer called?

Answer 46

The water table

Question 47

When does the water table rise or fall

Answer 47

The water table can rise or fall depending on factors like rainfall, drought, or extraction.

Question 48

What is a fossil aquifer

Answer 48

A non-renewable store of ancient groundwater that was formed under climatic conditions and is no longer being replenished by the current climate.

Question 49

What is a saline aquifer

Answer 49

A saline aquifer is an underground water-bearing rock formation that contains salty or brackish water instead of fresh water (Essentially an aquifer that contains saline water).

Question 50

Examples of Temporal changes in cryospheric processes

Answer 50

-During the last ice age (approx 18,000 years ago), ice sheets covered 30% of land, today only 10%. -Interglacial periods (e.g. 3 million years ago) saw higher temperatures, melting ice and faster water cycles -Today only 1.7% of Earth’s water is in cryospheric stores, compared to much more in the past

Question 51

Examples of spatial changes in cryospheric processes

Answer 51

-95% of cryospheric water is stored in Antarctica (90%) and Greenland (5%) -Melting at the poles would cause significant spatial changes globally (e.g. sea level rise) -Shrinking arctic sea ice in summer reduces albedo and changes regional climate feedbacks

Question 52

What percentage of Earth’s water is freshwater

Answer 52

2.5%

Question 53

Ways that Long-term global temperature change can impact the water cycle

Answer 53

-Cryospheric store reduction - melting -Increased evaporation and transpiration rates -More extreme wetather -Shifts in Runoff and River Flow -Soil moisture impact

Question 54

The role of crypospheric changes in the water cycle

Answer 54

The cryosphere acts as a long-term store of freshwater, as 68.7% of Earth’s freshwater is stored in glaciers and ice caps Water travels slowly through cryosphere and has long residence time, it stabilises the water cycle in the long-term When water exits the cryosphere as ice caps melt, this releases water from long-term storage into active cycling, increasing sea levels and the size of hydrospheric storage.

Question 55

Temporal changes in Lithospheric processes regarding the water cycle.

Answer 55

-Deforestation over decades - reduces interception and infiltration, increasing surface runoff -Soil degradation over time - Reduces soil’s ability to absorb and store water. -Land use change - Increasing impermeable surfaces, reduced infiltration and increased runoff.

Question 56

When does cloud formation occur

Answer 56

When warm air cools down, causing water vapour to condense into water droplets, which condense as clouds.

Question 57

What is required for clouds to form other than water droplets?

Answer 57

Condensation nuclei, tiny particles that the water droplets can condense upon to form clouds.

Question 58

What is the process of accumulation (cryospheric processes)

Answer 58

-The input of snow and ice into a glacier or ice mass, increasing the magnitude of the cryospheric store

Question 59

What is the process of ablation (cryospheric process)

Answer 59

The loss or output of mass from a glacier, decreasing the magnitude of the cryospheric store

Question 60

What is stem flow?

Answer 60

Water running down a plant stem or tree trunk

Question 61

What is base flow

Answer 61

Groundwater flow that feeds into rivers through river banks or river beds.

Question 62

What is interflow

Answer 62

Water flowing downhill through permeable rock above the water table.

Question 63

What is channel flow

Answer 63

Water flowing down the river or the stream itself.

Question 64

What is a drainage basin?

Answer 64

The area surrounding the river where the rain falling on the land flows into that river. It is also called a river catchment

Question 65

True or false: Drainage basins are systems

Answer 65

True as they have inputs and outputs

Question 66

What is the water balance?

Answer 66

The water balance shows the balance between inputs (precipitation) and outputs (channel discharge and evapotranspiration)

Question 67

Explain the water balance during wet season

Answer 67

During wet seasons, precipitation exceeds evapotranspiration, so there is a water surplus. Ground stores fill with water so there’s more surface runoff and higher discharge.

Question 68

What occurs with the water balance after a water deficit during wet seasons?

Answer 68

Ground stores are recharged in the next wet season as there’s a deficit of water in ground stores.

Question 69

Explain the water balance during dry seasons

Answer 69

During dry seasons, evapotranspiration exceeds precipitation, some water is lost through the river or some is used, so stores deplete. This means there is a water deficit

Question 70

What is river discharge

Answer 70

The volume of water that flows in a river per unit of time

Question 71

Relationship between runoff and discharge

Answer 71

High runoff causes high river discharge

Question 72

What is peak discharge?

Answer 72

The highest point on the flood hydrograph, where river discharge is greatest.

Question 73

What is meant by lag time?

Answer 73

The time between peak rainfall and peak discharge.

Question 74

What are the factors affecting runoff and the shape of the flood hydrograph?

Answer 74

-Size of drainage basins -Shape of drainage basin -Ground steepness -Rock and soil type

Question 75

How can the size of the drainage basin affect runoff and the hydrograph?

Answer 75

-Larger drainage basins catch more precipitation, so will therefore have a higher peak discharge than smaller basins. -Smaller drainage basins will have a shorter lag time, because the precipitation has to travel a shorter distance to the river than larger basins.

Question 76

How can the shape of the drainage basin affect runoff and the hydrograph shape?

Answer 76

-Circular basins are more likely to have a flashy hydro graph than long, narrow basins. Because all points of the watershed (boundary) will be the same distance from the point of discharge measurement. So more water reaches river at the same time.

Question 77

How can ground steepness affect runoff and hydrograph shape?

Answer 77

-The steeper the ground, the faster surface runoff will flow into the river, reducing lag time. -Run off is also higher as water will have less time to infiltrate the soil.

Question 78

How can rock and soil type affect runoff and hydrograph shape?

Answer 78

-Impermeable rocks and soils don’t store water or let water infiltrate. This increases surface runoff. -Therefore peak discharge will increase as more water will reach the river instead of being infiltrated.

Question 79

What are the 3 ways that humans have affected runoff

Answer 79

-Farming practises -Land Use Change -Water Abstraction

Question 80

Ways that farming practises has affected runoff

Answer 80

-Ploughing - breaks up the surface so more water can infiltrate, reducing runoff -Crops increase infiltration and interception compared to bare ground, decreasing runoff. Also evapotranspiration increases. -Livestock, such as cattle, trample and compact the soil, decreasing infiltration and increasing run off. -Irrigation can increase run off as not all of the water will infiltrate.

Question 81

Ways that land use change has affected run off

Answer 81

Deforestation - reduces the amount of water that is intercepted by vegetation, increasing the amount of water that reaches the surface so more runoff. Dead vegetation also stores water preventing it from flowing as run off, when this is removed run off is increased Construction of new buildings and roads creates impermeable surfaces meaning water can’t infiltrate so run off increases.

Question 82

How much of Earth’s carbon is stored in the lithosphere?

Answer 82

Over 99.9% of the carbon on earth is stored in sedimentary rocks.

Question 83

How much of earth’s carbon is stored in the cryosphere

Answer 83

0.01%