Cycles

Question 1

Define Input (In a system)

Answer 1

Material or energy moving into the system from outside.

Question 2

Define Output (In a system)

Answer 2

Material or energy moving from the system to the outside.

Question 3

Define Energy (In a system)

Answer 3

This is the power or driving force.

Question 4

Define Stores/Components (In a system)

Answer 4

The individual elements or parts of a system.

Question 5

Define Flows/Transfers (In a system)

Answer 5

The links or relationships between the components.

Question 6

Define Positive Feedback (In a system)

Answer 6

A cyclical sequence of events that amplifies or increases change, promoting environmental instability.

Question 7

Define Negative Feedback (In a system)

Answer 7

A cyclical sequence of events that damps down or neutralises the effects of a system, promoting stability and a state of dynamic equilibrium.

Question 8

Define Dynamic Equilibrium (In a system)

Answer 8

This represents a state of balance within a constantly changing system.

Question 9

What is the difference between lithosphere, hydrosphere, cryosphere and atmosphere?

Answer 9

• The lithosphere is the outermost solid layer of the earth, contains the crust and the upper mantle (Land).
• The hydrosphere is all the water on/surrounding the Earth, such as the ocean, rivers and water in the atmosphere (Liquid Water).
• The cryosphere is the frozen parts of Earth’s surface including ice caps, glaciers and snow cover (Frozen Water)
• The atmosphere is the air that surrounds the Earth (Air)

Question 10

How much of the world’s global water is freshwater?

Answer 10

Only 2.5%

Question 11

Which two stores of water remains the longest and the shortest?

Answer 11

Longest store = Groundwater (10,000 years)

Shortest store = Soil water (1-2 months)

Question 12

Define Precipitation (A process in the water cycle)

Answer 12

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

Question 13

Define Evaporation (A process in the water cycle)

Answer 13

Transfer of water from liquid state to gaseous state (Water Vapour). The vast majority occurs from the oceans to the atmosphere.

Question 14

Define Condensation (A process in the water cycle)

Answer 14

Transfer of water from a gaseous state to a liquid state, for example, the formation of clouds.

Question 15

Define Sublimation (A process in the water cycle)

Answer 15

Transfer from a solid state (Ice) to a gaseous state (Water Vapour) and vice versa.

Question 16

Define Interception (A process in the water cycle)

Answer 16

Water intercepted and stored on leaves of plants.

Question 17

Define Overland Flow (A process in the water cycle)

Answer 17

Transfer of water over the land surface.

Question 18

Define Infiltration (A process in the water cycle)

Answer 18

Transfer of water from the ground surface into soil where it may then percolate into underlying rocks.

Question 19

Define Throughflow (A process in the water cycle)

Answer 19

Water flowing through soil towards a river channel.

Question 20

Define Groundwater Flow (A process in the water cycle)

Answer 20

Transfer of water very slowly through different rocks.

Question 21

Define Percolation (A process in the water cycle)

Answer 21

Water soaking into rocks.

Question 22

What are the stores within the water cycle?

Answer 22

• Rivers
• Lakes
• Soil and Groundwater
• Glaciers/Ice
• Trees and Vegetation
• Clouds/atmospheric

Question 23

What factors can change the magnitudes of stores in the water cycle?

Answer 23

• Deforestation- Prevents interception and infiltration rates, but increases overland flow. (This reduces the vegetation stores and soil stores, but increases river and lakes stores)
• Urbanisation -If slopes are developed, impermeable surfaces will reduce infiltration, however water will travel much quicker through drains and pipes. (This reduces the soil stores, but increases river and lake stores.
• Farming - Ditches drain the land and encourages water to flow quickly to rivers. Irrigation increases the amount of water on the ground as well. (This reduces the vegetation stores , however increases river and lake stores as well as the soil/groundwater stores.
• Storm - Intense rainfall increases the amount of rainfall reaching the ground and increases the magnitude of stores. (This is increasing all stores in this system at the expense of another system)
• Seasonal Change - Winter snowfall and frozen ground interrupts the water transfers and affects the magnitude of stores. (This reduces all the stores besides the glaciers and ice store)

Question 24

What are the flows within the water cycle?

Answer 24

• Evapotranspiration (Evaporation and Transpiration)
• Precipitation
• Overland flow
• Infiltration
• Percolation
• Groundwaterflow
• Throughflow
• Overland Flow
• Streamflow

Question 25

What is the main inputs in the water cycle?

Answer 25

Precipitation

Question 26

What are the main outputs in the water cycle?

Answer 26

Evapotranspiration and Streamflow

Question 27

What is a drainage basin?

Answer 27

A drainage basin is the area of land that is drained by a river and its tributaries. The edge of a river basin is also marked by a boundary called watershed.

Question 28

Is the drainage basin system an open or closed system?

Answer 28

It is an open system, with inputs (precipitation) and outputs (runoff and evapotranspiration).

Question 29

What is the water balance expressed as?

Answer 29

``` P = O + E + Change in S Where: P = Precipitation O = Total runoff E = Evapotranspiration S = The change in the storage (in soil and rocks) ```

Question 30

Why is understanding the water balance a good idea?

Answer 30

Because this helps hydrologists plan for future water supply and flood control by understanding the unique hydrological characteristics of an individual basin.

Question 31

How do you calculate discharge? (m^3s^-1)

Answer 31

Cross sectional area (m^2) x velocity (ms^-1)

Question 32

What is a flood hydrograph?

Answer 32

This is a graph showing the discharge of the river over time following a particular stormy event.

Question 33

What are the characteristics needed for a short lag time and high peak hydrograph? (Using basin size, drainage density, rock type, land use, relief, soil water and rainfall intensity)

Answer 33

``` Basin size: Small Drainage Density: High density Rock Type: Impermeable Land Use: Urbanised area Relief: Steep slopes Soil Water: Saturated soil Rainfall Intensity: Heavy rainfall > Infiltration rates ```

Question 34

What are the characteristics needed for a long lag time and low peak hydrograph? (Using basin size, drainage density, rock type, land use, relief, soil water and rainfall intensity)

Answer 34

``` Basin size: Large Drainage Density: Low density Rock Type: Permeable Land Use: Forests/green areas Relief: Flat land/gentle slopes Soil Water: Dry soil Rainfall Intensity: Light rainfall < Infiltration rates ```

Question 35

What are the human factors that can affect the water cycle?

Answer 35

- Irrigation from Farming. - Land-Use change (Urbanisation/Deforestation). - Water Abstraction (Industry, domestic purposes)

Question 36

What are the natural factors that can affect the water cycle?

Answer 36

- Seasonal Weather - Drought - Severe Storms