Lesson 2 - The Drainage Basin Hydrological Cycle

Question 1

What is a drainage basin?

Answer 1

A drainage basin is an area of land drained by a river and its tributaries and separated from neighbouring drainage basins by a ridge of high land called a water shed.

Question 2

Give some examples of inputs to the hydrological cycle?

Answer 2

• Precipitation, all of the ways in which moisture comes out of the atmosphere
• Solar insolation (energy from the sun)

Question 3

Give some examples of outputs from the hydrological cycle?

Answer 3

• Transpiration, evaporation from plant leaves
• River flow or discharge, river taking water out of the drainage basin

Question 4

State five physical factors that can affect the drainage basin?

Answer 4

• The relief
• The climate
• The vegetation
• The geology
• The soils

Question 5

How can the relief affect the drainage basin?

Answer 5

The relief can impact the amount of precipitation. Slopes can affect the amount of runoff.

Question 6

How can the climate affect the drainage basin?

Answer 6

The climate has a role in influencing the type and amount of precipitation overall and the amount of evaporation, i.e. the major inputs and outputs. It also has an impact on the vegetation type.

Question 7

How can vegetation affect the drainage basin?

Answer 7

The presence or absence of vegetation can have a major impact on the amount of interception, infiltration and occurrence of overland flow, as well as transpiration rates.

Question 8

How can the geology affect the drainage basin?

Answer 8

The geology can impact on the subsurface processes such as percolation and groundwater flow (and therefore on aquifers). Indirectly, it can alter soil formation.

Question 9

How can the soils affect the drainage basin?

Answer 9

The soil determines the amount of infiltration and throughflow and, indirectly, the type of vegetation.