Drainage Basin Changes

Question 1

Are drainage basins fragile

Answer 1

YES

The vast variety of transfers and stores leave drainage basin vulnrale to extreme changes in response to human and physical factors

Question 2

Temperature changes throughout the seasons or global warming can cause……………across the watershed whilst an increase in…………………..may lead to severe flooding

Answer 2

Mass droughts

Urbanisation

Question 3

Give the link between human and physical factors in causing change to the drainage basin

Answer 3

Both come hand in hand as both equally neutralise and amplify the impact upon a drainage basin

Relatively harmless storm becoming severe if it falls upon impermeable urbanised surfaces

Although human activities are not less impactful, they are more frequent

Question 4

Give the most prominent human impact upon the drainage basin

Answer 4

Land-use

Be it urbanisation or deforestation

Question 5

Give the impact of urbanisation on the drainage basin

Answer 5

Water can not infiltrate into the soil, increasing overland flow and thus leads to a probable flood

Question 6

Give an example of urbinisation exacerbating the impact of a storm

Answer 6

Hurricane Harvey - 2017

Scientist - urbanisation in the catchment area increased the risk of flooding by 2000%

High rise buildings, as well as impermeable tarmac, dictate how much rain falls during a storm

Combined, increased risk of flooding during Hurricane 21fold

Question 7

Give a quote by scientist Villarini about high rise buildings

Answer 7

“The larger surface ‘roughness’ in urban areas created a ‘drag effect’ on Hurrican Harvey that moved warm air further up into the atmosphere, thereby creating conditions favourable for cloud formation and precipitation”

Question 8

How does deforestation affect the drainage basin

Answer 8

Lack of trees = surface run-off and soil erosion, whilst reducing soil water stores

Contributes to floods

Trees roots keep the soil in place reducing the movement of sediment that can shrink rivers downstream

Question 9

Give another human activity that could damage the drainage basin

Answer 9

Water abstraction - for industry, agriculture and domestic purposes

Question 10

How does water abstraction impact the drainage basin

Answer 10

Low flow conditions on rivers, cause tributaries to dry up

Question 11

What is the most prominent physical factor in inflicting changes upon a drainage basin

Answer 11

Higher temperatures

Question 12

How does a higher temp increase flood risk (soil)

Answer 12

Greater evapotranspiration - soil moisture deficiency, reduction in water stores

SOil = drier - immpermable

When rain does come, infiltration is minor and surface run-off becomes more apparent - increased flood

Question 13

How does higher temperature increase flood risk (biosphere)

Answer 13

Droght = less vegitation

Affects the process of transpiration, infiltration and interception, more water ends up in rivers

Question 14

How are human and physical activities intertwined

Answer 14

Global warming = human activity

Global warming causing increased snowmelt, flash floods