Block 5 (Deficit Within The Water Cycle)

Question 1

Define deficit within the water cycle

Answer 1

Greater outputs than inputs to the water cycle, resulting in depletion of water stores

Question 2

What happens when water deficit is significant?

Answer 2

Drought

Question 3

What are the three main types of drought?

Answer 3

• Meteorological drought
• Agricultural drought
• Hydrological drought

Question 4

Define meteorological drought

Answer 4

Extended period of below average rainfall in a region

Question 5

Define agricultural drought

Answer 5

Insufficient moisture to maintain average crop yields

Question 6

Define hydrological drought

Answer 6

Shortages in water supplies in surface + groundwater stores

Question 7

What are the two main meteorological causes of drought?

Answer 7

• Seasonal precipitation variations

- Longer term climate change

Question 8

How are seasonal precipitation variations a meteorological cause of drought?

Answer 8

• In drier seasons, there is less precipitation
• Less precipitation prevents a high river discharge, as the river is not supplied directly via rain or by surface runoff or groundwater flow
• This causes drought

Question 9

How is long term climate change a meteorological cause of drought?

Answer 9

• Temps are increasing, altering the climate in various locations
• Weather patterns are generally becoming more unpredictable
• Some areas have more rainfall
• Some areas have less rainfall, causing deficit which leads to drought

Question 10

What is the case study that exemplifies meteorological causes of water deficit?

Answer 10

Lake Chad

Question 11

Give some examples of why humans require water

Answer 11

• Household activities (e.g. washing)
• Agriculture
• Industry
• Drinking
• Power production
• Transport

Question 12

What are the human causes of drought?

Answer 12

• Surface water extraction

- Aquifer depletion

Question 13

How is surface water extraction a human cause of drought?

Answer 13

• Water removed from rivers + other surface stores of water
• This water is used for a range of reasons
• The removal causes reduced size of these stores + sometimes drought

Question 14

How is aquifer depletion a human cause of drought?

Answer 14

• Humans extract water from aquifers for a variety of reasons
• This extraction prevents groundwater flows supplying rivers + inland bodies of water
• This can cause drought

Question 15

Define an aquifer

Answer 15

An underwater layer of water-bearing rock

Question 16

What are some properties of aquifers?

Answer 16

• Made of rock
• Porous (allow water to be stored)
• Permeable (allow water to flow through)

Question 17

How are aquifers different to wells?

Answer 17

Aquifers are stores only (only made into outputs when humans drill into them + extract water)
Wells are stores + outputs

Question 18

What is the case study that exemplifies human causes of water deficit?

Answer 18

Aral Sea

Question 19

If there is a deficit in aquifers (due to human depletion) how can this be fixed?

Answer 19

• Natural recharge

- Artificial recharge

Question 20

Define natural recharge

Answer 20

Recharge of aquifers by reducing extraction + allowing the water cycle to naturally replenish the store via percolation of precipitation + surface water

Question 21

Define artificial recharge

Answer 21

Recharge of aquifers by humans, as humans actively place water back into the store via a variety of methods

Question 22

Give 2 examples of methods humans can use for artificial recharge

Answer 22

PERCOLATION BASINS
- Water added to ground surface, increasing percolation rates

INJECTION WELLS
- Water pumped directly into the aquifer

Question 23

What is the case study that exemplifies aquifer recharge?

Answer 23

High Plains Aquifer