Channel incidents Bam

2008/10/01 Salih, Abdin1 | Salamat, Alireza2 Iturria: Elhuyar aldizkaria

• Ingeniaritza
• Hidrologia
• Historia
• Giza zientziak

The qanatas are water supply systems, with an underground tunnel attached to the surface by several wells. They have been made in zones without surface waters. Most of the water courses are underground, so that the qanatas reduce water losses due to infiltration and evaporation. Gravity force is used to drive water downstream of the channel, thus avoiding the use of pumps.

Qanats have a special place in the cultural, socio-economic, political and physical landscape of Iran. Although for centuries life has changed radically, qanatas are still important for the well-being of the community and are necessary for survival in many parts of the country. However, in recent years, there has been a decline in the number of experts who know how to use these systems.

Canals of Bam, victims of the earthquake

The area of Bam is the typical desert oasis, with an average annual rainfall of about 60 mm. In recent years, in addition, it has rained less than normal. Approximately 70% of the population of Bam and neighboring municipalities is directly or indirectly related to agriculture and is predominantly dominated by qanats. Until December 26, 2003, a class 6.5 earthquake destroyed the old city, the Qanatas provided 50% of the water it needed annually.

With most of the 90,000 inhabitants of the city in bed, the earthquake occurred at 05:28 in the morning, with the death of a third of the population and most of the survivors lost the house. More than 80% of the city's buildings were demolished by the disaster. Among them were other old buildings, such as the citadel and historical hydraulic structures called cultural heritage, the qanatas. The earthquake caused blockades in many qanats of Bam and many others fell. In some cases, the earthquake caused the water to infiltrate other qanats, thus increasing the flow of water.

Fortuitous archaeological discovery

In studies carried out shortly after the earthquake, archaeological remains of thousands of hectares appeared. It did not cause earthquakes to appear, they were on the ground, dispersed and abandoned for years. The archaeological research that is being carried out in this area has shown that this area is more important than was thought when preparing the report for the inclusion of Bam in the UNESCO World Heritage Centre. The oldest in Iran, and perhaps the world qana, appear to be in the Bam area.

It seems that the advantages of the natural location of Bam, located on a plain between two mountain ranges that receive rain and snow, have made this city so important in the invention and development of qanatas. The geographical situation of Bamen was optimal for the construction of shallow wells and qanat systems. In addition to being the oldest in Iran's Qana, the area has the highest qanat density, with about 375 lines of old traditional qanats and about 950 wells of different depths divided into several sections.

Bam's qanata systems reached their peak in the early Islamic era and lost strength in the XII. At the end of the twentieth century by the wars. Although the war somehow affected, the qanat system lasted, although the city never recovered its previous fame. However, being a landscaped city of a semicircular zone, the fascination generated by Bam has not diminished.

Farmers trying to rehabilitate qanatas

The development of the social structure of the area of Bam has been the subject of a great help from qanat. The construction of qanats is a hard and expensive work that has always been a collective action, with multiple beneficiaries and shared property. Access to qanatas water and water management is regulated by the team responsible for the use of water. The members of the responsible team are also water owners, many of them farmers.

The earthquake caused the poverty of these peasants, which made it even more difficult to rehabilitate the Qanatas. Meanwhile, prices skyrocketed due to the lack of skilled labor and material.

Intervention by UNESCO

After the earthquake, Iran tried to rebuild the qanatas that were damaged or totally destroyed, and the UNESCO office in Tehran offered its help. Its aim was to ensure greater protection and future management of qanatas. Six expert groups were asked to prepare detailed technical reports on Qanat's current situation and future prospects. These pages highlight some of his tips.

In the first phase of the project, in 2004, each group analyzed an aspect of the problem: The International Center of Qanats and Historical Hydraulic Structures analyzed from the engineering point of view the Bam qanatas, the Ministry of Agriculture and Agriculture from the agricultural point of view, the Iranian Organization of Cultural Heritage and Tourism from the cultural point of view, two experts of the UNESCO from the archeological point of view, the Office of Geology of Iran

Each participant made a report for their presentation at the workshop organized by UNESCO's Tehran office in the Bam qanatas in June 2005. In the second half of 2005 the reports were gathered and sent to the Iranian government. Then, the Ministry of Agriculture and Jihad presented the second part of the project: reconstruction and rehabilitation of qanatas. This process is still underway.

Since June 2005, the Tehran office of UNESCO, in collaboration with the International Centre for Qanats and Historical Hydraulic Structures of Yazd, which works under the auspices of UNESCO, has taught two training courses in qanats. Bamen was the first course and the second in Yazde in July 2007. A greater number of training courses are expected in this area.

The Ministry of Higher Education also collaborates with the training center on qanatas created in 2003 to ensure the correct management of qanatas in the long term. The centre is located in the city of Taft, near Yazd. Its qanatas are also well known. Students study geology and hydrogeology, history, archaeology, classification of qanats, traditional methods of construction and maintenance of qanats, operation of qanats, distribution of water and socioeconomic aspects.

On the other hand, it intends to extend the project to other countries of the group that assumes the Tehran office of UNESCO, which are the only way to supply water in many places. One of them is Afghanistan. He has prepared a report, in collaboration with UNESCO, on the project being carried out to complete the country's qanatas inventory.

The disaster of the Bam earthquake revealed the sophisticated culture of rational distribution of resources, which for many years had been abandoned. This ancient way of managing underground water was seen by everyone. It perfectly explains the human capacity to cope with water shortages, a capacity that before, now and always has great importance for arid and semi-arid areas.

Additional information:

Information on the international centre of qanats and historical hydraulic structures: www.qanat.info/en/index.php

Source: UNESCO. "The fall and rise of Bam's qanats", A World of Science, 6. vol. Nº 1, January - March 2008 (http://www.unesco.org/science/). Article translated and adapted by Elhuyar with the authorization of UNESCO.