causes of change in the water cycle

Question 1

what are the 5 natural processes which would cause change in the water cycle

Answer 1

seasonal changes, storm events, droughts, El Nino and La Nina, and cyrospheric processes

Question 2

what are the 3 human impacts that can cause change in the water cycle

Answer 2

farming processes, land-use change, water abstraction

Question 3

how do seasonal changes cause change in the water cycle

Answer 3

-there is less precipitation and more evapotranspiration in summer because of high temperatures
-there is reduced flows in the water cycle as in winter water is stored as ice
-reduced interception in winter due to deciduous trees losing their leaves
-increased evapotranspiration in summer

Question 4

how do storm events cause change in the water cycle

Answer 4

it causes a sudden increase in rainfall which leads to flooding and replenishment of some water stores, this factor would be unlikely to cause long-term change

Question 5

how do droughts cause change in the water cycle

Answer 5

-causes major stores to be depleted and the activity of flows acting within the water cycle to decrease
-this may cause long term change as they are becoming more common due to climate change

Question 6

how does El Nino and La Nina cause change in the water cycle

Answer 6

-the El Nino effect occurs every 2-7 years and causes warm temperatures in a predictable way
-the La Nina effect occurs every 2-7 years and causes cooler temperatures in a predictable way
-it is likely that climate change will cause more of these in the future

Question 7

how do cryospheric processes cause change in the water cycle

Answer 7

-in the past glaciers and icecaps have stored significant proportions of freshwater through the process of accumulation
-currently all the glaciers are shrinking making sea levels rise
-if all of the worlds glaciers and icecaps were to melt then sea levels would rise by around 60 metres

Question 8

how do farming practices cause change in the water cycle

Answer 8

-ploughing breaks up the surface which increases infiltration
-arable farming can increase interception and evapotranspiration
-pastoral farming compacts the soil which reduces infiltration and increases runoff
-irrigation removes water from local rivers which decreases their flow

Question 9

how does land-use change cause change in the water cycle

Answer 9

-deforestation reduces interception, evapotranspiration, infiltration increases
-construction reduces infiltration and evapotranspiration, but increases runoff

Question 10

how does water abstraction cause change in the water cycle

Answer 10

-this reduces the volume of water in surface stores
-water abstraction increases in dry seasons
-human abstraction from aquifers as an output to meet water demands is often greater than inputs to the aquifer, leading to a decline in global long-term water stores