ABSTRACT
Arid and semi-arid regions of the world are distinguished, primarily, on the basis of their annual precipitation sum. Most deserts and (semi-)arid regions occur between 10 and 35° latitude and receive generally less than 250 mm precipitation per annum. Important geomorphic processes in the dry regions of the world differ from those in more humid environments. Streams are intermittent or ephemeral and have very irregular discharges and many rivers do not debauch into the sea but end in inland depressions without outlet. Salt lakes are a common landscape feature and physical weathering processes are prominent, making water resources management a challenging task for the inhabitants. A direct consequence has been overstressed groundwater resources in some cases to such sever extents that sustainability is no longer feasible.
Qanats, artificial underground tunnels transporting water over great distances, were invented by the inhabitants of Persia. This type of system, generally using water from aquifer drainage, was to be applied in many other parts of the world such as Egypt, India, Greece, China, the Maghreb, and the Canary Islands. Still used today, qanats are built as a series of underground tunnels and wells that bring groundwater to the surface. Practical flow measurement and water distribution techniques alongside respecting water quality and water ethics were evidently part of a greater water culture in the arid-semi arid region of the world. Developed in antiquity, qanats are traditional systems of harnessing groundwater in water scarce regions to meet water demands. During times they have formed part of the socio-economical characteristics of their respective communities, however enduring for centuries; qanats are now in decline due to various reasons.
Application of Integrated Water Resources Management (IWRM) in arid-semi arid regions with the ultimate aim of sustainable groundwater management has indicated the great importance of qanats as source inputs into the general water resources model of these regions. Their simple structures, their harmony with the environment, their ability to tap groundwater in arid areas and perhaps above all their contribution to the cultural heritage are indications of their role in sustainable development of communities. Therefore their preservation and optimum utilization should be encouraged.
