5.2

Question 1

What is a drainage basin?

Answer 1

the area that a river and its tributaries receives and loses water

Question 2

What are the inputs to the drainage basins hydrological cycle?

Answer 2

precipitation
human activity
surface runoff
meltwater

Question 3

What are the outputs?

Answer 3

streamflow
human activity
evaporation
evapotranspiration

Question 4

What are the flows?

Answer 4

groundwater flow
stream flow
meltwater flow
precipitation
infiltration

Question 5

What are the physical factors affecting the drainage basin?

Answer 5

climate- dictates how much evaporation, evapotranspiration and precipitation occurs, affects storage and flows

vegetation- water is stored in vegetation, so more vegetation means more interception

relief- If a steep gradient, speed of surface runoff increases and less chance of water storage

geology- more permeable rocks like sedimentary allow percolation (movement through rock) and increase ground water store, impermeable rocks like metamorphic and igneous increase flows to river

permeability of the soil- decides how much water infiltrated

Question 6

What are the human factors affecting the drainage basin?

Answer 6

agriculture- over abstraction and artificial adding of water disrupts processes and the system

deforestation- removes vegetation, lost permeability of soil meaning flooding more often

dams and reservoirs- interrupt streamflow and natural processes and regulates river

change in land use- includes all of the above and urbanisation which increases impermeable surfaces

Question 7

What are the 3 types of precipitation?

Answer 7

orographic- involves hills and mountains
convectional- involves solar energy
frontal- involves different air masses

Question 8

How does orographic rainfall happen?

Answer 8

1. prevailing winds bring warm moist air to the west
2. air forced to rise over hills
3. clouds form and when air cools and condenses it rains
4. it warms and becomes drier on the other side of hill
5. air and rain falls on the other side of the mountain
   E.g. Common in the west of the England

Question 9

How does convectional rainfall happen?

Answer 9

1. the sun heats the ground
2. the warm ground makes air rise which then evaporates
3. cumulonimbus clouds form at the dew point
4. heavy rainfall
   (the atmospheric cells contribute to rising air in the tropics)
   E.g. This is most common in the tropical rainforests

Question 10

How does frontal rainfall happen?

Answer 10

1. happens on a front where 2 air masses meet
2. warm air rises over cold air as cold air is denser
3. condensation forms clouds
4. rains heavily on the front
   E.g. commonly happens in Britain

Question 11

What is a case study for drainage basins?

Answer 11

E.g. The amazon
–> store of air in the atmosphere above the amazon decreasing
–> due to human activity such as deforestation, agriculture, Tavy and change in land use as increase in greenhouse gases is responsible for dryness
deforestation= less trees to take in carbon= more in atmosphere= global warming
–> amazon is important as it regulates climate as a carbon sink, due to its vast vegetation
–> 80% of convectional rainfall from evaporation in the amazon