W&C - The Water Cycle: Local Scale

Question 1

What are the inputs in the water cycle?

Answer 1

Precipitation

Question 2

What are the 3 types of rainfall?

Answer 2

Frontal, relief, convectional

Question 3

Describe frontal rainfall

Answer 3

• When two bodies of are at different temperatures meet, the warmer air rises over the cool air because it is less dense and therefore lighter
• This warm air rises and then condenses at higher altitudes, where it falls back down as rain

Question 4

Describe convectional rainfall

Answer 4

• sun causes temperatures to increase
• warm air rises, condenses at higher altitudes and falls back down as rain

Question 5

Describe relief rainfall

Answer 5

• warm air is forced upwards by a barrier such as mountains, where it condenses at the higher altitudes and falls as rain

Question 6

What are the outputs in the water cycle?

Answer 6

• evapotranspiration
• streamflow

Question 7

What is transpiration?

Answer 7

• the movement of water through a plant
• ends with the water being evaporated

Question 8

Name and explain the flows in the water cycle

Answer 8

Infiltration = water moving into the soil from the ground surface

Percolation = water moving from the soil into porous rock

Throughflow = water flowing through the soil

Groundwater flow = water moving through the porous rock

Surface runoff = water flowing over the surface of the ground

Streamflow = water moving through designated channels

Stemflow = water moving down a plant as a result of interception

Question 9

What are the stores in the water cycle?

Answer 9

Groundwater storage = water stored in the pores of rocks

Soil storage = water stored in the soil

Channel storage = water stored short term in river channels

Surface storage = water stored in bodies of water on the surface of the ground

Interception = water stored by plants before reaching the ground

Question 10

What is the equation for the water balance?

Answer 10

Precipitation = total runoff + evapotranspiration +/- change in storage

Question 11

Define the water balance

Answer 11

The balance between the inputs, outputs and processes within a drainage basin

Question 12

What is the soil water budget?

Answer 12

The annual balance between inputs and outputs in the water cycle and its impact on the soil water storage

Question 13

Describe the winter soil water budget

Answer 13

• soil moisture recharge
• water surplus
• minimum evapotranspiration
• increase in infiltration and percolation as precipitation refills water stores

Question 14

Describe the summer soil water budget

Answer 14

• evapotranspiration exceeds precipitation
• soil water utilisation
• minimal precipitation
• can lead to a water deficit if there is a long summer

Question 15

Name and explain the physical factors affecting the water cycle on a local scale

Answer 15

Storm events = large bursts of rainfall saturate the ground quickly
- doesn’t replenish water stores as effectively as prolonged rainfall because it does not allow for percolation to occur as much, instead increases surface runoff

Seasonal changes
- summer = low precipitation, high evapotranspiration
- winter = high precipitation, minimal evapotranspiration, less interception (plants have no leaves)

Question 16

Name and explain the human factors affecting the water cycle on a local scale

Answer 16

Deforestation - reduction in interception means soil gets saturated more quickly (higher rate of infiltration), reduction in percolation and an increase in surface runoff

Urbanisation - impermeable surfaces minimise surface runoff and percolation, and instead increase surface runoff and streamflow

Farming practices
Pastoral farming = livestock trampling on the ground reduces infiltration because the soil becomes more compact
Arable farming = crops can actually increase interception, however drainage ditches being made around the land can increase streamflow and surface runoff

Question 17

Give examples of how deforestation impacts the water cycle

Answer 17

• 17% of the Amazon rainforest has been deforested
• 20-30% of all freshwater in the atmosphere comes from evapotranspiration in the Amazon rainforest

Question 18

Give examples of how seasonal changes impact the water cycle

Answer 18

• monsoon season accounts for 75% of India’s annual rainfall
• up to 400cm of rainfall
• river flows in India can increase by 3-4 times