1. The Water Balance

Question 1

The water balance

Answer 1

Used to express the process of water storage and transfer in a drainage basin system.

Precipitation = Total runoff + Evapotranspiration +/- Storage

Question 2

Water cycle is impacted by…

Answer 2

1. Deforestation
2. Storm events
3. Seasonal changes
4. Agriculture
5. Urbanisation

Question 3

Deforestation

Answer 3

Removal of trees = less interception = Soil less able to store water = greater surface runoff

Question 4

Storm events

Answer 4

Increases surface runoff and water storage

Question 5

Seasonal changes

Answer 5

More interception in spring; snow reduces flows; hot weather reduces precipitation

Question 6

Agriculture

Answer 6

Pastoral (livestock) ground trampled so less infiltration.
Arable (crops) - ploughing increases infiltration. Ditches increase runoff.

Question 7

Urbanisation

Answer 7

Impermeable surfaces increase runoff

Question 8

Soil water budget

Answer 8

Shows the annual balance between inputs and outputs in the water cycle.

Question 9

Soil water budget - seasonal

Answer 9

• There is a surplus of water in the winter months, after recharge of soil water in autumn.
• Soil water is recharged in autumn because the inputs of precipitation exceed the outputs of evapotranspiration (because it rains more and is cooler)
• The water is utilised in spring and summer, when potential evapotranspiration of plants is highest due to warmer weather.