For rational management of groundwater a holistic approach, linked to the sustainable management of the ecosystem must be developed. It is demonstrated that ancient methods of groundwater management, such as the Qanats system, could provide a good example of human ingenuity to cope with water scarcity in a sustainable manner. The catastrophic earthquake of Bam has drawn the attention of researchers and professionals to a great human heritage related to the sustainable management of groundwater in arid zones and the development of a sophisticated culture of rational resource allocation.
Definition of Qanats
A Qanat is a system of water supply consisting of an underground tunnel connected to the surface by a series of shafts which uses gravity to bring water from the water table to the surface. Qanats are usually dug where there is no surface water and were originally invented by Iranians. The main, or mother, well, is generally excavated in the mountains, penetrating deep into the water table. Water runs down a slightly sloping tunnel, gradually increasing in volume until it emerges near farms or communities. Water from Qanats is brought to the surface where the soil has been enriched by sediments from alluvial fans. Cultivated land and settlement sites are situated downwards from the point where the water surfaces. The immediate outlet, mazhar, is the point where people take water and it is generally located in the main square of a village. The water outlet point is very important; it is well kept and cemented and water use is monitored. A tunnel channels water under the residential area to the cultivated land. A sloping corridor with steps leads from the surface to the payab. The first payab is located in the main square and is used for taking drinking water. A network of smaller payabs runs from the main payab Qanats are also known as ‘Karez’ (Afghanistan), ’Galeria’ (Spain), ’Khotara’ (Morocco), ’Aflaj’ (Arabian Peninsula), ’Foggara’ (North Afri ca), ’Kanerjing’ (China), ’Auon’ (Saudi Arabia/Egypt), reflecting the widespread dissemination of the technology across ancient trading routes and political maps.
Qanats in the World and in Iran
Qanat technology exists in more than 34 countries in the world, but most are concentrated in present day Iran, which has about 32164 active systems with a total discharge of about nine billion cubic meters (m3). The first recorded Qanats were dug in the north-western areas of Iran and date back to 800 BC (Western calendar). Since Iran has few perennial rivers and surface water resources, many of its communities have depended on Qanats for thousands of years. This unique and environmentally sustainable system has created cultural and natural ecosystems that ideally addressed the specific needs of each community. Digging Qanats involves a huge amount of work and engineering skills originally developed in Iran and exported across the world.
The Qanats of Iran have a special niche in the cultural, social, economic, political and physical landscapes of the country. Without these kinds of hydraulic structures, thousands of villages and towns would not have been theme at all. Although life in Iran has changed radically over the centuries, Qanats have maintained their importance and significance at the heart of community well-being and survival of many communities in that country.
Groundwater management, particularly in arid regions, should be viewed holistically and linked to the sustainable management of the ecosystem. Only through consideration of the interaction between the groundwater and other environmental components can it be possible to elaborate a long-term program for rational groundwater use and protection. Ancient methods of groundwater management, such as the Qanats system, provide an excellent demonstration of human ingenuity to cope with water scarcity. The catastrophic earthquake of Bam has drawn the attention of researchers and professionals to a great human heritage related to the sustainable management of groundwater in arid zones and the development of a sophisticated culture of rational resource allocation.