Human Activities Change Processes In The Hydrological Cycle Flashcards
What % of all water falls as precipitation
0.0035%
Is water a renewable resource?
Yes as it constantly recycles each year
What happens if humans release water from store with a long residence time?
Effectively exploring a non-renewable resource
How might humans try to solve problems of inconsistent supply of water
Storing water
Abstracting from aquifers
Abstracting from rivers and lakes
Transferring water from one place to another
Desalinating water
How can global population rise affect demand
Increase in people means more water for drinking food and crop production
How does increased irrigation affect supply
70% of global water supply used in farming particularly in intensive farming which can significantly affect down stream flow and local supply
How does industrialisation affect demand of water
As countries become more developed and turn to industry they often use more water
COCA COLA INDIA
How does increased per-capita use affect supply of water
As countries develop people use more water in their lives
Showering cleaning and leisure
Reducing supply
What 4 human activities affect the hydrological cycle
Agriculture
Deforestation
water abstraction
Urban development
What is water abstraction
Removing water from there natural stores
Some may return to the river some may not resulting in reduced flow downstream
What is an example of an Over exploited rivers?
The ARAL SEA (SYR DARYA AND AMU DARYA RIVERS)
Good example for the impacts of over abstraction and damaging irrigation
What crops were irrigated from the ARAL sea
Cotton
Rice
What is the remaining Aral Sea like?
90% what remains is highly polluted by pesticides and fertiliser
What is an aquifer
A body of rock that is able to hold water
They are both permeable and porous
What is permeability
The ability for water to enter a rock due to the crack or pace spaces it contains
What is porosity
The ability/volume within the rock that is able to hold water
What are the most porous rocks
Chalk
Sandstone
Limestone
What is salt water incursion
The movement of saline water into the freshwater aquifers
What causes salt water incursion
Water is abstracted to quickly
The water table drops
This reduces pressure
In costal areas sea water is pulled in
Problems from over-abstracted aquifers
Rivers and lakes fed by aquifers if the water is abstracted sources will run dry
Aquatic and semi aquatic plants will die if wetlands dry out
If an area relies on an aquifer their supply could run out
How can over-abstracting aquifers cause subsidence
Lack of water between the pores means there is nothing to support the pores spaces so they collapse
What is the problem with subsidence
The collapse causes damages to buildings and pipelines
Where has subsidence occurred
London
Chalk aquifer
Saw degree of subsidence
