West of Indus Plains and out of monsoon zone is Balochistan – the largest landmass in Pakistan with an area of 343,000 square kilometres.
Balochistan is scarcely populated, mainly due to its daunting arid geography. It includes the mountainous country separated by intervening valleys. Balochistan receives very low rainfall annually. But innumerable natural springs known as “Karez” and streams are found in most of the areas.
The ancient Karez system is comprised of a series of wells and linking underground channels that uses gravity to bring ground water to the surface, usually far from the source. Originally ancient towns used to depend on the streams and rivers nearby into which glaciers in far-off mountains used to feed. As the time passed the glaciers gradually shrank over the centuries, the streams they fed likewise diminished, resulting in less water flowing downwards. Then people ingeniously created the Karez to draw the underground water to irrigate the farmland. Wells begin at the base of the mountains along the contours of the hillside. To keep the underground channels unclogged, two men and a draught animal work as a team – one man is lowed down to clear the tunnel and buckets of mud are hoisted to the surface by the animal. The tunnels slope less than the contours of the geographical depression, so that the water reaches close to ground level. The water in Karez will not evaporate in large.
This technology that originated in the Chinese deserts west of the Himalayas is also commonly used in the highlands of Balochistan, although with some minor modifications. Though it is not known how it reached here. Small water channel that are built along the hill gradient for maintaining the proper gravity flow of water are found in Balochistan in many places.
The Karez irrigation systems rely on gravitational pull and are comprised of simply a water source, underground tunnels, and vertical shafts that feed the water scarce areas. These irrigation systems are owned and operated wholly by the community. Some work is being planned on to re establish the Karez irrigation system at the sub-tehsil level.
The ancient and social water supply system can be reactivated for obvious reason: To improve the socio-economic status of the people of Balochistan, by helping them realize the importance of the Karez system and facilitate self-help activities for rehabilitation of the same; to identify and understand ground water irrigation system deficiencies and the causes for its abandonment by the community; to re-instil a sense of confidence in the Karez system among local communities; to protect, excavate and extend the Karez system in the other areas; to incorporate a delay action mechanism in the Karez system and to check the dam for efficient groundwater recharge; to train community leaders in the efficient operation and management of Karez.
Cleaning of Karez is considered collective social responsibility and people work for it on self-help basis (like bhall Safai in Punjab). Once there existed a large network of these Karez’s in the province. The system has very low operational cast, it not only fulfills daily need of usage of water but also irrigates orchards and supply water for cultivation. We should try to keep the system alive. These are social streams as well.