Context: As Taliban are set to overtake Kabul; but an expert believes they will spare( carry forward) the age-old Karez system of underground aqueducts in the country given its importance.

Background

• The resurgent Taliban is on the victory march to Kabul, in this context we discuss its old age practice of conservation of water.
• Some 9,370 Karezes were operating in 19 Afghan provinces.
• The centuries old Kariz system should be rehabilitated and promoted as traditional means of irrigation and drinking water supply.
• The educational value of this historic system is highly relevant in the present days of water disputes that are prevailing at local, regional, national and international level.

Historical Evidence

• The Karez is found in 38 countries worldwide and of course most of these are concentrated in the Middle East region. Persia is known for the earliest known and documented Karez system.
• The Muslim dynasties with ruling class descending from Persia or having influential connections with Persian kings may have invited expert engineers from Persia.
• The silk route may have been the information highway to transfer the cultural and traditional knowledge.

About

• Karez system is considered as the global human heritage since it is not only a traditional water supply system of exploiting groundwater,
• It reflects the culture, socio-economy, and history of the ancient civilizations that had utilized them for thousands of years in arid and semi-arid regions of the world. 
• Karez is constructed as a series of well-like vertical shafts.
• It is connected by sloping tunnels, which tap into subterranean water in a manner that efficiently delivers large quantities of water to the surface by gravity, without the need for pumping.
• It is built from an upland aquifer to ground level.
• Its water to be transported over long distances in hot dry climates without loss of much of the water to evaporation.

Distribution

• Some historians and archaeologists have attributed people in the southeast Arabian Peninsula as the first developers. 
• Others, however, ascribe it to the ancient Persians. 
• Thousands of miles away from West Asia, the ancient peoples of Peru’s Pacific coastal desert also independently developed a similar system called ‘puquios’.
• It covers eight per cent of irrigated land in Afghanistan.
• They are the only source of water in the majority of rural communities in the southern and southwestern regions of Afghanistan
• It came to the Indian Subcontinent during the 800-year-old Islamic Period.
• The system was brought in the Indian Subcontinent during the Bahamani Sultanate, founded by Alaudin Bahman Shah. 

Advantage 

• It is being resistant to natural disasters such as earthquakes and floods, and to deliberate destruction in war. 
• It is almost insensitive to the levels of precipitation, delivering a flow with only gradual variations from wet to dry years. 
• It is environmentally sustainable as it has no additional energy requirement and, thus, has low life cycle operation and maintenance costs.

For India

• Karez system is not only economically robust over the long term, but also a viable water supply technique for irrigation and domestic uses.
• The karezes should be protected as indigenous human heritage, and at the same time, they can be utilized as a sustainable way of water resources management in the arid regions to enhance water resiliency under changing environment.