Drought Case Studies (CS)- WATER CYCLE

Question 1

Drought case studies

Answer 1

• Aral Sea
• Lake mead

Question 2

What are key stats for Aral Sea? (Pollution- water unsuitable for use due to salt)

Answer 2

• located in Asia and is a transboundary lake with half in Kazakhstan and in Uzbekistan
• in 1950 the Soviet Union decided that rivers that fed into the Aral Sea will be diverted in order to irrigate the desert and supply water to grow rice and cotton
• based on creating dams of which 40,000 km of canals would irrigate fields daily
• Due to this diversion less water reached Aral Sea causing it to shrink in size

Question 3

Impacts of the Aral Sea ?

Answer 3

• increased scarcity of water so fish and marine life dies Causing real sea industry to be ruined
• it used to employ 40,000 people and produce 1/6 of soviet unions entire fish industry
• reduce flow in Aral Sea meant salt blown onto surrounding area and camels died as a result as the grass they consumed were too salty (one fisherman lost camels)
• many factories relied o the Aral Sea to transport goods and when sea dried up the tarde route it disrupted and led to closure of factures and loss of jobs for many meaning less economic outputs
• respiratory illnesses were common such as TB, cancer, digestive disorders ad infectious diseases due to dust containing highly toxic chemical and fertilisers blowing from dried sea
• high child mortality rate of 75 in every 1000
• drinking water supplies are low and water contaminated with pesticides and other agricultural chemical leading to viruses
• 24 types of species are now extinct
  10,424 m^2 of river have become desert and layered with toxic salt
• only few dozen of 180 species survived due to lack of water
• water level dropped by 16m
  -Volume reduced by 75%
• In 1950 10g per litre of water salinity but now increase to 26g which is too High for marine life to survive

Question 4

What are key stats for lake mead ?

Answer 4

• largest reservoir in the US
• supplies water to millions in 7 states
• suffered long term drought
• in July 2022 it was at 27% of capacity
• 83% of the state in drought
• lake last approached full capacity in 1999
• 10% of water comes form local precipitation and groundwater with the rest from snowmelt
• is a national recreation area
• water declining due to climate change and 30 years of ongoing drought
• 5/6 boat ramps closed
• boat ramps become more difficult and expensive due to topography and protection decline in water levels
• countinues to recede