‘Karez’ system of irrigation

‘Karez’ system of irrigation

Part of: Prelims and GS – III – Methods of agriculture

In news Karez, being one of the types of water management and irrigation systems in Afghanistan, is under threat under the resurgent Taliban rule.

What is a Qanat / Karez?

• This system of underground vertical shafts in a gently sloping tunnel is built from an upland aquifer to ground level.
• They are energy efficient and green since they use the force of gravity rather than any machines running on fuel.
• It has its origins in Persia and later spread to Arab and Turkic lands. 
• The entire system is a planning and execution of the forces of a watershed. 
• The wastewater is never mixed with drinking water. 

• Water in them does not evaporate and is also filtered till it comes to the surface. 
• There is no depletion of the aquifer since excessive use is impossible. 
• Its maintenance is also low-cost.
• The first Karez system in India was built in the city of Bidar of Karnataka during the reign of Bahamani Sultan Ahmad Shah Wali (1422-1436), who shifted the capital from Gulbarga to Bidar.

News Source: DTE

Afghanistan & Threat to Karez

• Afghanistan, a semi-arid country, is losing its northern and central mountain glaciers due to climate change.
• These glaciers provide meltwater to people, especially in rural areas through Surface water or canals, underground water or borewells and Qanat / Karez.
• The Karez system has the potential to solve problems of water in Southern and southwestern regions of Afghanistan as there is no other water source. 
• Some 9,370 Karezes are operating in 19 Afghan provinces with the majority of them concentrated on the eastern, southern and western flanks of the Hindu Kush mountains.
• These are part of the ‘Pashtun Crescent’, the heartland of the Pashtuns, the main ethnic group in the Taliban and the country’s largest ethnicity. 
• Several Karezes have been destroyed in the more than 40 years of war in Afghanistan since the Soviet invasion in December 1979.