Subterranean Landscape

The Far-Reaching Influence of the Underground Qanat network in Ancient and Present-Day Iran

Fluid Motion Architects (FMA) was recently involved in the design and execution of a project in Tehran that required the excavation of the site, during which came the discovery of two qanats: ancient Persian water networks that tap into underground mountain water sources. These subterranean water canals were gushing out such a large amount of water that they actually brought the excavations to a halt. In order to solve the problem, FMA consulted one of Tehran’s main qanat experts, Ahmad Maleki, with whom the firm collaborated for three months on a plan to divert the qanats. This introduction to the qanat network proved an invaluable experience. It not only provided knowledge of their organization and construction, but also a much more far-reaching understanding of the extent of their influence on ancient Persian cities and the possibilities they hold for today’s urban development.

Invented 3,000 years ago by the ancient Persians, the qanat is a hydraulic structure. Employing gravitational force, it can extract groundwater without consuming any energy. There are 50,000 qanats in Iran, 600 of which, (with a total length of 2,000 kilometers 1,243 miles), are in Tehran. Dating back 700 years, Mehrgerd is the oldest existing qanat in the capital. Bastani Parizi described in his preface to Qanat in Iran (2005)  how all the largest cities in ancient Iran were riddled with qanats; even those such as Tabriz, for instance, that had a river and relatively high rainfall.¹ Parizi proceeded to explain how this legacy could be fully tapped into today. The Alborz mountain range, for instance, which is one of the largest water resources in Iran, has the potential, if the rivers, streams and valleys radiating through it could be integrated into an engineered plan to support new settlements. It could be possible to have around a hundred cities of a million inhabitants in a 1,000-kilometre (621-mile) range, from Khorasan in the northeast to Azerbaijan in the northwest. By fully utilizing the Alborz’s snow and glacier melting water, sufficient crops could be cultivated on the Alborz range to feed as many as a 100 million people.

The role of the qanat in providing not only the technical means of supporting Persia’s ancient civilization with a ready supply of water for drinking and irrigation, but also in assisting in the creation of a rich and diverse culture, is highlighted by Mohammad Hossein Papoli Yazdi in his book The Quassabeh Qanat of Gonabad.² He points out that if qanats had not been invented some 3,000 years ago, large villages and cities would not have developed, and agriculture, industry and trade would not have evolved across some of the most arid and semi-arid regions of the earth, particularly in Asia and southern Africa. In areas with low rainfall and no spring water, sustainable life would have been impossible without groundwater and the qanat system.

Furthermore, the qanat network had an even more far-reaching impact, directly informing the structural urban fabric and affecting the social fabric. In the cities that were supplied by qanat water, it was impossible for both the rich and the poor to live far from qanat aqueducts. All would therefore settle in the same neighborhood, along the qanat network, and use the same mosque, bazaar, bathhouse and zourkhaneh (a place for traditional Persian sports) and, as a result, interacted directly face-to-face on an everyday basis. Yazdi concludes by asserting the qanat as the main influencing force ‘in the foundation of urbanization, civilization, and agriculture in extensive parts of plains and mountainsides on the earth’.3

Revealing a New Urban Topology

For many years the formal geometries of ancient monuments, like the palaces, castles and grand mosques at Yazd and Isfahan, for example, seemed entirely at odds with the wider urban fabric that appeared fluid, dynamic and even illogical.

From time to time, this urban flow even unexpectedly changed its direction; a shift that accorded neither with the geographical directions nor with the direction of the Kiblah (Kaaba in Mecca). This flow surrounds both modest structures such as houses, and larger and more prominent public buildings and monuments (the beauty of this integration is that the geometric structures and large plazas float in the whole fluid flow of the city). Moreover, over the last 50 years studies of Iran’s ancient cities by distinguished contemporary Iranian architects and prominent non-Iranian researchers have constantly overlooked this fluid and dynamic flow. Analysis of the Iranian city has remained focused on the palaces, bazaars, and public or religious buildings. The understanding of Iranian architecture has been limited entirely to this perception of architectural structures as having regular and symmetrical geometry, details and motifs. The organization of the urban fabric has only been assessed in either the vaguest terms or been regarded as somewhat haphazard: broken or destroyed to widen paths, in the course of city development and current constructions. Only valuable buildings of the urban fabric have been preserved or frozen, in the hope that they will bring a touch of the past to new streets. The key question remains unanswered: What is the underlying structure of the ancient cities of Iran? In arid and semi-arid regions of Iran, could it be the qanats that provide the topological structure of the ancient urban fabric?

Looking at the first series of aerial photographs taken of Iranian cities in the 1950s 4, the fluid flow of urban fabric is absolutely evident, as are the points at which it is severed and transformed to voids by regular Cartesian grids of newly built streets. If we follow the fluid structural lines of cell-like houses, the old city appears. This condition could be regarded as an ideal solution for restoring the old damaged fabric and replacing it with Modern architecture to attain a harmonious and efficient combination, upholding the complexity and spatial depth of the existing city fabric.

Unfortunately, qanat maps of all of Iran’s historic cities are yet to be generated. So it cannot be precisely determined what is happening beneath the cities’ undulating surfaces and which paths the qanats run through. The only existing map is for the qanats network of Tehran, which contains some defects and ambiguities. But based on this map, produced by water systems experts, the logic of the relationship between the subterranean qanat systems, gardens, courtyards and generally green spaces on the surface of Tehran city is absolutely clear. As an example, a part of Sangelaj old qanat and the large green spaces connected to it, from Daneshjou Park to Shahr Park, and their peripheral residential fabric are displayed. These maps and diagrams show that the qanat structure links large and small pieces of gardens and courtyards like a thread and with its flexible and fluid geometry that indicates groundwater flow systems, it has formed fluid and complex structures of buildings on the ground. This system, which was based on the organic movement of the groundwater, had developed spatial character of city architecture in Iran before the establishment of Tehran’s modern water piping systems in 1955. Another important fact is that the plateau of Iran is an earthquake-prone region and this vast area is formed by a collection of tectonic plates, which are distinguished from each other by fault lines.

The natural structure of fault lines in the historical cities of Iran on the one hand, and the man-made qanat networks on the other, are the two hidden topological systems under the visible layer of cities that are linked together. For instance, the relationship between the geographical location of Tehran and the northern foothills can be regarded as tripartite: 1) it was dictated by its proximity to the mountains, which accumulated an adequate amount of snow in the highlands in the winter (see A in the diagram opposite); 2) it was determined by the fault and fracture lines that border the mountains and plains and enable snow water to penetrate deeply into the earth (B); and 3) the city’s position in relation to the mountains was governed by the gradient of the mountain range, which is about 10 per cent, gradually decreasing as one moves away from the mountain (C).

Iranian architects then designed a system of aqueducts under the surface of the ground with regard to the underground water tables that were stored naturally below the earth’s crust. They used the qanat networks structure (D) gravitational force and the natural slope of land to supply water to the ground’s surface and create the required gardens and green spaces for cities and residential areas.

In the second half of the 20th century, with the construction of the modern system of tap water and drilling deep wells, this organic and sustainable system was ignored and gradually forgotten. In all of Tehran’s comprehensive urban plans in the past 50 years, these valuable structures under the city’s surface have remained neglected.

After the revolution in Iran, Tehran’s rapid expansion and numerous constructions have led these priceless structures to be cut, occluded or desiccated in the construction process whenever a new building, expressway or, more recently, subway lines meet a qanat’s paths. Fortunately, in the northern and central parts of the city, there are still many active qanats. Tehran’s big blobs of green space like the Abbasabad Hills, Taleghani Park and Pardisan Park remain irrigated by these qanats for free.

Greening Tehran

Today, Tehran suffers from a shortage of urban open spaces, such as squares and plazas. The parks and sidewalks of the main streets comprise the major public spaces, and are insufficient considering the size of the city. An uncontrolled increase in the number of cars and buildings in the past two decades (since the Iran–Iraq war), heavy traffic and air pollution have not only affected and faded the experience of walking in the city, but have also transformed Tehran to a dense city that lacks properly proportioned spaces.

In the latest masterplan for Tehran, in 2006, a system of green spaces had been designated using five river valleys radiating from the mountains to the north of the city. Unfortunately, with the construction of new expressways, these areas are now dominated by cars; they can therefore only be seen from inside a car and there is no possibility for the public to experience these spaces as parks or properly maintained leisure areas. Excessive development in recent years, particularly in the northern parts of the city, has resulted in a loss of gardens and valuable green spaces and has transformed them into compact high-rise buildings.

Tehran is the eighth most polluted city in the world, and the number of days that air pollution has crossed the risk border in the cold season has amounted to more than a month. This has made it uncomfortable to live in the city during the day and has caused serious dangers to the health of children and the elderly. Using the existing qanat structures underneath Tehran’s surface and the new subway system, it is possible to imagine an underground city where the weather and environmental conditions are controlled and which provides a place for people during months when air pollution is unbearable. The idea of an underground garden city is reminiscent of the ancient structure of Tehran, described by travelers and historians as an underground city with many gardens. In 1009, the traveler Ebn-e-Houghol Moahamad Baghdadi described Tehran as a village in the north of Rey city with many gardens and a variety of fruits, and mentions that the deviants of Tehran whose profession was robbery lived underground. In 1203, Shahab-e-din Yaghout Hemavi describes Tehran as a large village with underground houses.

Subterranean Tehran could first be constructed in scattered patches, and in some appropriate places of the city built structures on the ground level and their active functions moved underground. The remaining ground could be changed into a garden. An increase in usable land surface and the propagation of underground urban patches would increase the amount of green spaces on the ground level. Little by little Tehran would transform into a garden city once again.

Undulant walkways could be created along qanat routes linking new gardens to one another. To achieve this, a number of paths would need to be identified and the buildings along those paths, those without any specific architectural value, purchased and redesigned. It would then be possible to enjoy walking in Tehran and to experience the city from a new perspective; an experience that has been forgotten in recent years. A garden city for walkers inside hectic Tehran conjures up the idea of expressways being replaced by walkways. A set of paths along a series of underground gardens could be an alternative to jammed streets.

In conclusion, as the Iranian plateau is located in a hot and arid region, the invention of qanats as a system for managing underground water was a crucial factor in the development of urban life in this area. The most important historic Iranian cities were formed based on these principles, and thus their future growth is also dependent on serious consideration of the use of qanats. Their importance, in addition to their role as a system of water management, is their topology and fluid structure that has the potential for creating dynamic, mysterious spaces, such as those of ancient Iran.

Text © 2012 John Wiley & Sons Ltd.

[1] Ahmad Maleki and Ahmad Khorsandi Aghaee, ‘Qanat in Iran: The Case Study of Tehran Qanats’, , Urban Planning Press, Tehran, 2005, pp 3, 7.

[2] Mohammad Hossein Papoli Yazdi, ‘The Quassabeh Qanat in Gonabad’, Khorasan Water Department Press, Tehran, 2000, pp 9, 235.

[3] ibid

[4] Taken by the National Cartographic Center of Iran.