Over abstraction case studies - Aral Sea, Orgallala, Uk chalk stream

Question 1

Aral Sea (Central Asia)

Answer 1

Cause: Over-diversion of rivers for irrigation of cotton fields in the 1960s.

Soviet engineers began diverting water from the Amu Darya and the Syr Darya, after Soviet central planners had calculated that the rivers were worth more if they were used to grow crops in the desert.

Impacts:
- By 2005, the Aral Sea had lost 80% of its water.
- Most of the fish and 60,000 fishing jobs disappeared.
- 3 million people in the area suffered from high rates of cancer, respiratory ailments and anaemia due to millions of tonnes of salt and toxic dust exposed on the sea bed.

Response: Kok-Aral Dam in 2005 to revive the northern sea by raising levels by 3m, efforts for water-saving farming.

Question 2

Uk Chalk Streams

Answer 2

Cause: Over-extraction of groundwater for urban and agricultural demand in southeast England.

Impacts: 40% critically low/reduced river flows, loss of biodiversity, and water quality degradation.

Response: Water conservation efforts, regulated abstraction, and catchment management to protect stream health.

Question 3

Orgalla Aquifer (USA)

Answer 3

Cause: Excessive water extraction for irrigated agriculture (mainly in the Midwest) = 8 states

Impacts: Falling water levels by 100 feet, subsidence, and threats to agriculture and food security, 30% depleted by 50 years

Response: Adoption of sustainable irrigation techniques, drought-resistant crops, and water recharge methods.

Silicon Valley electronic industries store their waste solvents in tanks underground.
Authorities conducted an inspection they found 85% of tanks were leaking.
60% of the US’s liquid hazardous waste is injected directly into the ground
waste is injected deep below drinking water sources but has leaked and entered aquifers affecting many states