Water Cycles Human Induced Changes Over Time Flashcards
Effects of arable farming on the interception and evapotranspiration
Arable farming increases interception and evapotranspiration
what are the impacts of ploughing on infiltration
ploughing breaks up the surface, increasing infiltration
What are the effects of pastoral farming on infiltration and runoff
Pastoral farming compacts soil, reducing its porosity, reducing infiltration and increasing runoff
What are the impacts of irrigation practices
Irrigation removes water from local rivers, decreasing their flow
What did irrigation lead to in eastern Peloponnesus Greek Argolid plain?
To a 400 m seawater intrusion
What percentage of Argentina’s arable land is covered by soya bean?
60%
What did increased harvesting of soya in Argentina lead to in river Morro basin?
A rise in water tables, increase in overland flow and flooding
Why soya bean harvesting is leading to flooding?
Soy bean has short roots and grows for only a few months each year, thus reducing interception store during the year
What effect did irrigation had on Aral see?
By 2007 Aral see declined to 10% of its original size due to irrigation
On which scale do farming practices mainly have impact on?
Local scale
How contour ploughing in the Gina river (Ethiopia) helps to manage the impacts of flooding?
It reduces soil erosion by 50%, controlling runoff water and increases infiltration
How much of floods in the UK on local scale are attributed to runoff from farmland?
14%
How does deforestation affects the water cycle?
deforestation reduces interception, evapotranspiration and increases infiltration
How much or tropical region of South America was converted to cattle pasture through deforestation?
10%, it generates 1/4 of the world’s river discharge
What is an effect of water abstraction on the surface water stores?
Reduces amount of water in surface stores
What is a long-term effect of human induced water abstraction from aquifers?
human abstraction from aquifers as an output to meet water demand is often greater than inputs to the aquifer, leading to a decline in global long-term water stores
By how much did river Po (Milan region) water tables sink in the last 80 years?
By 25-40 m
How much of global fresh water is held in aquifers?
0.7%
How much of global fresh water is held in soil?
0.005%
To what % deforestation does not have significant impact on a drainage basin?
When less than 20% of basin is deforested
How construction and urbanization affects water cycle?
Construction and urbanization reduce infiltration and evapotranspiration, but increases runoff
How an increase of 530% in the paved area of Long Island, New York affected the total runoff?
There was 270% increase in total runoff
Which factors will cause the greatest change in the operation of water cycle?
It is a combination of human activity and natural variation will cause the greatest changes to the water cycle
