Aquifiers

Question 1

what are they?

Answer 1

a storage area for ground water made of permeable porous rock (eg limestone, sandstone or chalk)
water is extracted through boreholes and wells or can escape through springs and contribute to river discharge
the upper surface of saturation is the water table -> this can recharge

Question 2

what is an Artesian Basin?

Answer 2

See gallery

Question 3

Beijing case study

Answer 3

• pop= 20 million
• it sits on dry plain where H2O has accumulated over millennia -> drilling wells = decreases the water table -> soil compacts like dry sponge
• sinking by 11cm/yr cos of excessive groundwater pumping. this poses great threat to infrastructure like skyscrapers and train operations (derailments).
• the subsiding is most prevalent in CBD
• use INSAR to monitor changes in land elevation
• 10s of 1000s of water wells exist around the city
  . they are used in farming and landscaping
  . the power over their installations have been inconsistent

to combat the water crisis
- phase out 367 wells
- ban new water well construction near completed rail lines
- 2015 = £46bn South-North water divide
. 2,400km canals + tunnels to divert 44.8bn cubic m of H2O to capital

Question 4

Turkey case study

The rivers Tigris and Euphrates

Answer 4

• the sources of the rivers are in Turkey. Turkey created dams that restricted flows to Syria and Iraq.
• Southeastern Anatolia Project (GAP)
  . cost £32bn
  . to harness pwr + potential of rivers to irrigate fields
  . completed 21 dams and 17 hydro electric pwr plants by 2010 -> produces 22% of Turkey’s projected elec requirements
• the Ataturk Dam
  . completed 1993
  . generates 8.9bn KWH in elec + irrigates 180,000 acres of farmland
  . 6th largest rock filled dam in world
  . key structure in lower Euphrates -> decreased water content from 30bn m3/ yr to 16bn m3 at Syrian border.
• water can be used by downstream countries
  . quality decreases cos of chem in fert + pesticides
  -> this = prob for Iraq cos 74% of areas suffer from Salinity
  . Iraq constant fear that Turkey + Syria use all the water
  -> this has caused conflict since 1940s
  • tension increase cos more water used by GAP project
  • 1974 = Iraq soldiers in Syrian border threaten to destroy Al-Thawra dam on Euphrates
  • animosity toward Turkey = great over shared water resource in Arab region