topic 4.1.b/c - processes of the water cycle

Question 1

What is the water balance?

Answer 1

Summarises the flows of water in a drainage basin overtime.
Precipitation = evapotranspiration + streamflow +- storage

Question 2

What are the flows within the water system?

Answer 2

The principal flows that link the various stores are
* Precipitation
* Evaporation
* Transpiration
* Run off
* Infiltration → the vertical movement of rainwater through the soil
* Percolation → the movement of surface and soil water into underlying permeable rocks.
* Throughflow → water flowing horizontally through the soil to stream and river channels

Question 3

What is precipitation and what forms does it take ?

Answer 3

the water and ice that dallas from clouds towards the ground
Forms : rain,snow,sleet,hail,drizzle

Question 4

How does precipitation occur?

Answer 4

1) It forms when vapour in the atmosphere cools to its dew point and condenses into water droplets or ice particles to form clouds
2) Eventually these droplets aggregate and reach a critical size and leave as precip..

Question 5

How does precipitation vary ?

Answer 5

• some experience seasons such as more rain in winter months in the uk
• Duration is the length of time that a precipitation event lasts → prolonged events linked to depressions ,au deposit excess precipitation = causing floods

Question 6

What is transpiration?

Answer 6

the diffusion of water vapour into the atmosphere from the stomata of plants

Question 7

how much of moisture in the atmosphere is transpiration responsible for?

Answer 7

10%

Question 8

What are the factors affecting rate of tranpiration? (4)

Answer 8

• Wind intensity → ^ wind more moisture lost
• Temperature → ^ temp = increased rate
• Surface area / type of vegetation
• Density → amount of vegetation

Question 9

What is condensation?

Answer 9

the phase change of water vapour to liquid water
* Occurs when the air is cooled to its dew point and at this critical temperature the air becomes saturated with vapour resulting in condensation

Question 10

What are the three types of clouds?

Answer 10

1. cumuliform
2. stratiform
3. cirrus

Question 11

What is a Cumuliform cloud?

Answer 11

Flat bases and considerable vertical development

• Form when air is heated locally through contact with earth surface
• Causes heat particles to rise through atmosphere (convection) expand (due to fall in pressure with altitude) and cool
• As cooling reaches the dew point condensation begins = clouds

Question 12

What is a stratiform cloud?

Answer 12

• Develop where an air mass moves horizontally across a cooler surface → together with mixing and turbulence (aka advection)

Question 13

What is a cirrus clouds?

Answer 13

• Form at high altitude consist of tiny ice crystals
  They do not produce precipitation → have a little influence on water cycle

Question 14

Fog

Answer 14

Condensation at or near the ground produces dew fog → both types of condensation deposit large amounts of moisture on surfaces

Question 15

infiltration def

Answer 15

vertical movement of water into the soil

Question 16

interception spatial / temporal variation

Answer 16

• Interception less from grasses due to smaller surface area of grass shoots → interception increases with crop density
• Coniferous trees > intercept more in winter than deciduous this switches in summer
• Seasonal changes in storage occurs in biomes that have a lot of deciduous vegetation

Question 17

Surface water def

Answer 17

There are a number of types of surface water some of which are temporary and some are permanent.

Question 18

Surface water spatial / temporary variation

Answer 18

• Temporary sources - puddles / turloughs (seasonal lakes)
• Permanent stores - lakes, wetlands, swamps , marshes, peat bogs

Question 19

Ground water - spatial / temporal variations

Answer 19

• In small drainage basins → seasonal variations more noticeable then large
• Due to extraction by humans many of groundwater stores been depleted

E.g ogallala aquifer in texas experienced fall of water table

Question 20

Groundwater definition

Answer 20

Refers to the subsurface of water that is stored underground.
Accounts for 22.7% of all freshwater on earth