MONITORING SOME SELECTED QANATS OF YAZD IN ORDER TO SIMULATE THEIR RAINFALL-RUN OFF OPERATION

Yazd, an important city in the middle of Iranian Kavir desert with more than 423,000 inhabitants, is very well known for the presence of several qanats all over the territory, some of which are very ancient, but still perfectly working. The network development of these underground hydraulic systems runs for several hundred kilometers. For this reason and taking into consideration their specificity and cultural interest, UNESCO declared 11 of them as mankind heritage and established in Yazd a Center for the study of these underground hydraulic systems (ICQHS). Thanks to an agreement signed between UNESCO-ICQHS, IMC-CNR and the University "Niccolò Cusano" started the project to carry out a joint research on the Qanats of Yazd. For the safeguard of these systems and of the related water sources, it will be important to define the conceptual models of their operation and water drainage. In particular it will be important to complete/update the evaluation of the architectural features and the stability/safety of the tunnels and of the service/entry structures, if the case defining and implementing specific monitoring points. Moreover it seems strategic to implement also a continuous monitoring system (possibly remote controlled) of the flow rate; to well define the areas for the recharge and capitation of a single selected qanat; to understand the relationships among the meteoric and underground water contributions and to clarify the hydrogeologic aspects of the underground water circulation intercepted by qanat; to characterize these resources under the chemical and quantitative aspects (flow rate put forward and losses/withdrawal along the itinerary), stressing the possible variations; the weather related trends and, at the end, to elaborate suitable tools to support operational decisions (numerical models implemented in GIS environment). To perform these activities we are studying the possibility to use open-source tools and to develop cheap equipment for the monitoring. To ensure the usability/compliance with safety standards of these hypogeum systems it is relevant also the monitoring of the possible presence of radon in the water and of radon indoor along the tunnels, in the underground rooms and in the service/entry structures, stressing (taking into account the significant linear and aerial development of qanat system) the areas where there is a higher concentration, the possible origin and the suitable mitigation actions. The monitoring of the possible presence of radon gas in the underground structures relates to qanats will offer an additional element for the cultural tourism of Yazd qanats. Radon in high concentration can pose a threat to human health, and these days qanat underground galleries are frequently visited by two groups of people: qanat workers and qanat tourists. Now qanat is being brought to the fore in the tourism sector and, in case it proves that visiting qanat galleries is harmful to the visitors' health, it would be a devastating blow to this industry at its infancy. Therefore measuring the concentration of Radon in qanats can help us better figure out what to do in order to safe the visitors against any possible danger related to Radon.