Qanats and surangams are examples of water accessing systems which have similar technologies. Qanat technology originated in Iran and was used extensively in the dry, arid desert regions of the Middle East and surangam technologyis used in the hilly terrains of the Western Ghats. Both systems essentially consist of underground tunnels that source the aquifer and use gravity to convey the water to groundlevel.
In both systems, construction is undertaken by hand by labourers or farmers. The most important aspect of building these structures is identifying the source of water. The traditional Qanat builders, called muqannis, follow the water courses coming down the mountains and identify subsurface water sources. They dig a trial well to test the quantum and flow of water before beginning work on the Qanat. Similarly, in India, workmen who traditionally undertook the digging of surangas, were people who were familiar with the slopes, soil structure, catchment areas and used their knowledge of local flora and fauna to identify water sources.
|Physical conditions||Arid, desert region with high surface evaporation rates. Absence of rivers||Coastal hill areas underlain by lateritic and weathered rocks with high rainfall. Rapid discharge of river water due to steep slopes|
|Type of structure||A series of wells connected by a tunnel||Tapping groundwater directly|
|Length of tunnel||30 – 150 m sometimes as long as 6000 m to 8000m||3 - 300 m|
|Height||1m - 1.5 m||0.9 -15 m|
|Width||0.5 – 1m||0.5 – 0.8 m|
|Vertical shafts||At intervals of 20 – 35m||Generally no shafts unless tunnels are very long|
|Style of construction||Began from where water was to be delivered and worked its way up the slope to mother well||Began from the source of water|
Qanats: Originating in Armenia 2,500 years ago, Qanats have reemerged into the international spotlight as “rational irrigation systems,” says Dr. Ali A. Semsar Yazdi the Director of the newly formed International Centre on Qanat and Historic Hydraulic Structures (ICQHS) in Yazd, Iran.
Today in Iran, more than 34,355 of the structures are still functioning. Sophisticated, self-regulating, and structurally sound, Qanat systems were an integral part of Iranian cotton production in the ninth and tenth centuries AD, and have since been found in 35 countries including China, India, Egypt, and even as far westward as Spain and Peru.
Qanats (also called kariz, lyoun, aflaj) use underground water channels to drive the natural flow of aquifers to the earth’s surface for irrigation and domestic use. An intricate series of vertical shafts run from a point source near a hill or mountaintop and continue downhill to a field or village extending between one kilometer (km) and 70 km in length.The Qanat system was used widely across Persia and the Middle East for many reasons. First, the system requires no energy, reliant on the force of gravity alone. Second, the system can carry water across long distances through subterranean chambers avoiding leakage, evaporation, or pollution. And lastly, the discharge is fixed by nature, producing only the amount of water that is distributed naturally from a spring or mountain, ensuring the water table is not depleted. More importantly, it allows access to a reliable and plentiful source of water to those living in otherwise marginal landscapes.
Anthony Smith, a well known author covering the social importance of Qanats in Iran, explains the system as “the life of the village, without it, the village would be dust. The systems can deliver water at a rate between one liter per second and 500 liters per second, and a single Qanat can irrigate hundreds of hectares.The well is horizontal, instead of vertical, relying on gravity and pressure from upland shafts to channel water up to the surface.
Over the centuries, the abundance of Qanats has varied amidst shifting dynasties and new landowners. More recently, the resurgence of Qanats is fighting years of inevitable modernization in which wells and piped water systems were constructed for growing populations under new land arrangements. Variable and decreasing rainfall have also hindered development efforts. In Syria, 92% of all Qanats have run dry since the introduction of pumped tube-wells in the mid-1970s. In both Syria and Iran, Qanats were constructed in areas that received 100-300 millimeters (mm) of precipitation each year. According to Professor Dale Lightfoot at the University of Colorado, these areas have received more variable rainfall in recent decades, compromising the efficacy of Qanats. Time and money is also a serious obstacle to new construction. New systems take anywhere between 25 and 75 years to construct with traditional materials and strategies.Thus, ICQHS focuses its resources in village-level education, training users how to revitalize and repair existing Qanats. Since 2008, ICQHS has taken on six projects to restore Qanat systems in villages surrounding the Center in Yazd, successfully increasing drinking water and irrigation supplies.
Similar to the technology of quanats is the surangam technology that was in vogue in Dakshin Kannada district of Karnataka and Kasaragod district of Kerala. A Surangam is basically a tunnel dug through a laterite hillock through which water seeps out and into the tunnel. Water is then collected at the end of the tunnel in a storage pit. A surangam is also known as thurangam, thorapu, mala in different parts of Kasaragod. The only cost of the a surangam is the initial cost of digging which was done by local workmen who were familiar with the geology, soil, slope etc.
Generally a surangam was about 0.45–0.70 m wide and about 1.8-2.0 m in height. The length of the tunnel varied between 3 m to 300 m. For long tunnels, air shafts were provided to ensure atmospheric pressure. Surangams are dug in places where the hydrogeological profile consists of is lateritic and weathered rocks. Surangams are used to provide water for drinking, domestic use and sometimes even for irrigation. According to Harish Halemane of Kasaragod, there are about 2000 surangams in Bayar village in Kasaragod. In Sheni village in Kasaragod, there is a 90-year old, 250 m long surangam with seven air events.
In Manila village in Dakshin Kannada district, Achyut Bhat’s family dug nearly 20 surangams, of which 14 are still functional. The family’s 15 acre property lies in a rocky area, where it digging a well is not economical. Today, the plot has areca nut and cocoanut gardens. Achyut Bhat is passionately committed to the idea of surangams and has propagated the idea in his village. He says that there are about 300 surangams in the village.
1. Surangam providing irrigation water in Padre village. 2. Surangam being constructed.
Anthony Smith: Explorations in Persia: Blind White Fish in Persia. Richmond, Virginia: William Byrd Press, 1953, pp. 16-17
Gunther Garbrecht, "Ancient Water Works - Lessons from history".Impact of Science on Society, UNESCO 1983 No.1; p.10.
Lightfoot, Dale R. Syrian Qanat Romani. Water History.
Salih, Abdin, Qanats a Unique Groundwater Management Tool in Arid Regions: The Case of Bam Region in Iran, International Symposium on Groundwater Sustainability (ISGWAS)
Boustani Fardin, Sustainable Water Utilization in Arid Region ofIran by Qanats, World Academy of Science, Engineering and Technology 43 2008
Padre, Shree, Surangas, manmade caves to tap underground water, India Together, http://www.indiatogether.org/2006/mar/env-suranga.htm.
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Harish Halemane,Suranga - a sustainabale water resource, June 2007, National seminar on water & culture- Hampi, Karnataka
Anon, Dying Wisdom, Rise, fall and potential of India’s traditional water harvesting systems, Centre for Science and Environment, 1998, pp 220-222