3.a. human factors can disturb and enhance the natural processes and stores in the water and carbon cycles

Question 1

dynamic equilibrium in the cycles and the balance between the stores and the flows

Answer 1

Feedback loops-

Climate change -> warmer temps ->

++
more evapotrans -> higher humidity -> more cloud cover -> more insulation -> warmer temps

conditions become drier -> trees die due to droughts -> less transpiration -> lower humidity -> less cloud formation -> less precipitation -> even dryer conditions

–
more evapotrans -> higher humidity -> more cloud cover -> reflecting incoming solar radiation -> cooler temps

Question 2

the land use changes acting as a catalyst for altering the flows and stores

Answer 2

urbanisation
deforestation
farming
forestry

Question 3

how does urbanisation act as a catalyst for altering the flows and stores

Answer 3

Concrete surfaces -> impermeable -> reduced infiltration -> less storage in ground rock more run off -> higher discharge into rivers -> more storage in rivers -> floodings

Roads -> disrupt drainage systems

Drains -> carry water from urban areas to rivers quickly -> increasing storage in rivers

Question 4

how does deforestation act as a catalyst for altering the flows and stores

Answer 4

Less interception -> less storage in biosphere (trees + soils) -> more run off -> more storage in rivers + floodings e.g. 2014 Madiera river -> evacuation + cholera outbreak -> 60 killed

Less transpiration -> precipitation is 20% lower as a result

Question 5

how does farming act as a catalyst for altering the flows and stores

Answer 5

Machinery compacting soil -> reduces infiltration + increases run-off -> more water in river stores

Irrigation of farmland -> over abstraction of water from groundwater or other stores -> and putting it on land

Ploughing land -> increasing soil temperatures -> increasing evaporation -> less water stored in soils

Underground irrigation systems -> adding more water to soils

Question 6

how does forestry act as a catalyst for altering the flows and stores

Answer 6

Adding vegetation
-> more interception -> less run off
-> less infiltration + percolation
-> more transpiration

Question 7

how water extraction, including surface extraction and sub-surface groundwater extraction (including aquifers and artesian basins) impact the flows and stores in these cycles

Answer 7

Increased in recent years due to ->
Increased agriculture + manufacturing -> to accommodate for the growing demand

Removal of groundwater stores + flows
Meaning less storage in rivers -> as less water is discharged via groundwater flows

Over extraction at a faster rate than the aquifer can recharge -> groundwater stores depleted

E.g. in the River Kennet
Taken way too much -> aquifers cannot recharge -> less water fed into rivers

temporal variations-
e.g. chalk beneath London
Less industrialisation -> less factories -> water abstraction was the highest the early 1900s -> declining in the last 50 years -»» water table has recovered to normal levels -> however -> will likely see more abstraction in future due to new licensing to abstract

Artisan basins-
Where sedimentary rocks form a sink rock -> and aquifers are confined between impermeable rock layers -> which are under artesian pressure -> meaning water travels at a higher pressure