Aqueduct (Qanat) with Old History, a Hidden Treasure in Desert Town, Kashan

Water is used by living organisms in different forms and qualities. But in most points through the world and Iran we are encountered with potable water shortage, particularly in Iran in central wells and Loot desert with precipitation about 50mm annually are considered as low precipitation points in the country and such precipitations are very limited in average globally. This indicates that in some regions, Iran, particularly southern and central parts and desert boundaries such as Kashan encounters with low precipitation. On the other side, 25 million ha out of 165 million ha of Iran’s area are classified among saline lands that by development of irrigation agriculture, particularly in the regions lacking drainage systems of lands and deserts, particularly enjoying from traditional methods, the saline lands are increasing day to day and water sources are also reducing and Kashan town is also suffering from this crisis. Because Iran has been located in the dry and semi dry climate, therefore, about 800 BC, for supplying their needed water, Iranian decided to make aqueducts. The average annual precipitation of Kashan is about 140.3mm and potential evaporation in this region is about 2181 annually (Abtahi, 2001). This forced Kashan people, like other regions of Iran to exploit from ground water that are relatively stable sources called “Aqueduct”. Kashan where has 628 aqueducts, possessed aqueducts more than what can be seen today. For example, in Kashan desert, there were 252 aqueducts but most of them lost due to draught and desert winds and earthquakes. On 1965, they reduced to 130 and on 1981 reduced to 62and in recent year they reduced to 46 and this tragic situation results from increasingly digging the deep and semi deep wells as well as harsh expediencies and lack of supervision on ground water sources. Therefore, for maintaining the sustainable development of this old town as well as preventing water crisis, it is required to find a cure and this paper aims to deal with it.