Salinisation

Definition= The accumulation of salts (e.g. chloride, sulphate, carbonate, salts of sodium, calcium, magnesium) in the soil.

Why is it a problem?

1. Accumulated salt crusts may be difficult for plants to penetrate.
2. These salts are toxic to many plants.
3. They reduce the spaces available for moisture and air in the soil.

The Process:

• Salts are present throughout the soil but are not concentrated enough to damage plant life.
• Occurs where land has been cleared of trees and then irrigated without proper drainage.
• This causes the water table to rise nearer the surface lead to low vapour pressure in soil pores driving capillary action drawing moisture to the surface.
• SALTS ARE LEFT ON THE SURFACE AS A CRUST

Fact: 80% of irrigation projects in Uzbekistan have been lost to this process

Agriculture-Aral Sea

Location:

• Scale= 68,000km2 (in 1964)
• 60% lost 1964-1987
• 90% lost by 2002
• found between Uzbekistan and Kazakhstan
• Fed by the Syr Darya and Amu Darya (no longer fed by the sea)

Opportunities:

• Farmer used water for cotton (irrigation)
• Cotton (cash crop) successfully exploited

Challenges:

• Double salt concentration 
• Salinisation of the sea
• Collapse of fishing industry 
• Native organisms have died out 
• Lowering of groundwater levels
• Exposed sea bed (dustbowl contaminating land several hundred km inland)

What did the government do?

• Tried to introduce new fish species (doesn't tackle root problem)
• Cost-benefit analysis
• Reliance on cotton (refused to stop cotton industry)

The Kokaral Dam (completed in 2005)

• In 2003 Kazakh. government used money from oil exports to build the dam.
• Since 2005 North Aral water level has risen by 10m.
• Wider variety of fish returned.
• Now over 80 fishing boats operating in the sea.
• 2009= 2400 tonnes of fish caught
• Thriving fishing industry attracting people back (improved local services, more investment in agriculture)

Future of the Aral Sea

South Aral:

• Little hope of saving major part of Aral (fewer fish, more saline, more wildlife will die out)
• Continued desertification (Local climate will become more acute with colder winters and hotter, drier summers.

North Aral:

• 2nd Dam funded by World bank ($126 million) will bring water level back to the port of Aralsk, is still currently some 40km from the waters edge.

Future aims for aral sea basin:

1) Develop management strategies to give sustainable water use/sustainable land resource uses.

2) Improve information base (need to plan the development of water resources in the area

3) Stop/reduce deterioration of environment

4) Improve conditions (for people and animals living close to the sea)