The city of Yazd is located in the center of Iran, in a vast dry rain shadow desert valley overlooked by the Shir Kuh, Iran's highest mountain range. Yazd was probably founded by the Sassanids, and grew in eminence as a junction of trade routes linking the cities of Isfahan, Kerman and Neyshabur. It has, since the Arab conquest in 642, continued to be an urban settlement shaped and characterized by mud domes and wind tower architectural forms, extensive subterranean canal systems (qanats) and quarters of Zoroastrian and Jewish minorities. The earliest known descriptions, dating from the tenth century describe a well-built, fortified city with iron gates, then known as Kathah in the larger province of Yazd.
The Kakuyids established a series of villages and reinforced the network of qanats around Yazd. Hence greatly contributing to the rapid urbanization of the region in the eleventh century. Yazd under the subsequent rule of the Atabegs survived the Mongol invasion of Persia in 1220 to later become a refuge for Islamic culture and learning. The Il-Khanid rule under Sayyid Rukn al Din in the fourteenth century witnessed an increase in construction with the use of the waqf as an instrument for urban development. The Muzaffarid conquest in 1313 ushered in an era of prosperity and development as Yazd became capital to the provinces of Kerman, Fars and Shiraz.
Large urban design projects were initiated and the city walls were rebuilt in 1346-7, nearly doubling the size of the city. The complex of Vaqt va Sat comprising of a shrine, library, college and observatory was constructed next to the Atabeg Friday mosque, which was itself reconstructed half a century later in 1375.The Timurid conquest reinforced Yazd's status as an important military stronghold in central Iran when defense walls and fortifications were added to the city's southern limits in 1395. Yazd became a center of religious education under the reign of the Timurid governor, Amir Chaqmaq. Yazd passed into Safavid control in the early sixteenth century, as a city of little importance and alternately part of the provinces of Fars, Kerman and Khurasan. The invasion and unstable rule by the Ghalzai Afghans in the 1720s furthered the city's deterioration with little new development till 1747. A succession of able governors beginning with Mohammad Taqi Khan (1747-1798) partially restored the city's lost glory with construction and repair of qanats, villages, gardens, caravan-serais and defense outposts.
Yazd's existence in an arid region was made possible by an extensive system of sloping subterranean man made infiltration tunnels which conduit fresh water from the surrounding highlands. Some of these conduits, called qanats are as long as 50 kilometres in length, though the most do not exceed five kilometres. The extreme climate also evolved architecture obsessed with insulation by mud bricks and thick walls as well as cooling by ventilation structures called badgirs. A badgir is a vertical wind catching structure on the roof that directs and cools trapped wind over small water pools within the building.
Bonine, Michael Edward. "Yazd and its Hinterland: A central place system of dominance in the central Iranian plateau." Unpublished doctoral dissertation, University of Texas at Austin, 1975.
Lockhardt, Laurence. Persian Cities. London: Luzac & Company, 1960.
Yazd Province." Iran Travel and Tourism Organization. http://www.yazdcity.com/english/indexen.htm [Site inaccessible as of 11 August, 2016]
"Iranian Architecture." http://www.irania.tv/city/yazd/ [Site inaccessible as of 11 August, 2016]
Water reservoirs, or ab anbars as they are locally known, form the terminal end of extensive traditional water supply systems that make urban settlements possible in the Kavir desert region of Central Iran. Snow fed streams were tapped at the foothills of surrounding mountains and channeled through sloping subterranean canal systems (qanats), often over great distances to discharge into underground reservoirs within the city. These reservoirs were usually built at the center of city neighborhoods, and thus configure urban morphological form much in the same manner as their feeder canals (qanats) configure agricultural tract divisions. Hydrological, climatic and social criteria overlapped to evolve a distinct architectural form for these water reservoirs that now forms a distinct part of Yazd's architectural heritage and identity.
As is often with secular, public use structures, one cannot trace the precise origin or patron of most ab anbar reservoirs in Yazd. Though the earliest urban water supply constructions in Yazd are believed to date from the Sassanid period and many others have been continually repaired and used, most extant ab anbars can be today traced to the late Safavid and Qajar periods. The Shesh Badgiri anbar or 'Six wind catcher' reservoir was constructed in the Qajar period, while the Khan Bazaar anbar can be more accurately dated to Qajar ruler Nasr al-Din's reign. There are approximately 75-90 surviving anbars in Yazd today, and some of the important ones are the Seyed Va Sahra, Masoudi, Hadji Ali Akbari, Khajeh, Golshan, Rostam Geev, Kolah Doozha, Malekotojar and Mirza Shafi reservoirs.
The typical ab anbar consists of four key elements: the underground reservoir, the pasheer or platform, the dome, and the badgir or wind catcher shafts. Some of the larger and centrally located ab anbars also house a khazineh or public hot bath. The cylindrically shaped underground chamber often 10 meters below street level, maintain a stable low water temperature considerably below the summer sun baked ground surface. A descending staircase passageway approached the pasheer or foot of the faucet used to retrieve water. The semi-circular brick lined dome, visually much alike a Buddhist stupa, have escape vents in the center to cool water by air convection while protecting it from dust and other pollution. Four adjacent badgirs or weathering shafts, often at the cardinal directions would maintain fresh air circulation to prevent water quality deterioration. The hierarchy of urban space where anbars were sited would determine both its size and the scale of constituent elements. Thus, minor neighborhood anbars are usually endowed with fewer badgirs while larger, city center reservoirs are often serviced by six or more wind catchers. The access openings to the street were often decorated with intricate stalactite ornament while larger anbars often housed shops and coffeehouses in addition to public baths signifying an urban institutional status. Not infrequently bazaars, mosques, public baths and anbars would function together within a waqf (religious endowment) property. Ab anbars played a pivotal role in determining both Yazd's skyline and urban layout but are in a precarious state of preservation today with redundancy caused by modern piped water supply systems. Though few of the architecturally significant examples can be preserved, sustainable strategies to conserve traditional urban infrastructure systems like qanats, badgers, pigeon towers, dams and water mills need to be explored.
Bonine, Michael Edward. 1975. Yazd and it's Hinterland: A Central Place System of Dominance in the Central Iranian Plateau. University of Texas at Austin, Ph.D. Dissertation, 137.