Estimation and Conservation of Strategic Groundwater Resources Based on Probable Maximum Drought (PMD)

The pressure on ecosystem and the reduction of welfare and livelihood in human communities are one of the most important effects of drought which, if the severity and duration of this event increases, could become one of the most catastrophic natural disasters. Therefore, many countries have different climate-based policies in facing water stress issue, such as severe and prolonged droughts. However in almost all of them, groundwater has been considered as a strategic resource because of its reliability in water stress situations. Strategic groundwater resource refers to the volume of fresh groundwater that should be stored in an aquifer for various activities, especially for drinking water, and also to be gradually used for human needs in some serious long-term droughts. Strategic groundwater reserve is the most important support of water supply management in water stress conditions of "severe and prolonged droughts" particularly in arid and semi-arid areas. Unfortunately for many years, the concept of balancing water resources and developing sustainability has received little attention in Iran, consequently this unique water resource is continuously declining. This study sought the necessity of developing the concept of Probable Maximum Drought (PMD) as the basis for determining the maximum withdrawal of groundwater, as the most important factor for increasing resilient development in water stress conditions by preserving strategic groundwater reserves. The lack of attention to maintaining strategic resources could bring irreparable damage and cause changes in society. Finally, this study introduces suggestions for drought risk management based on the aforementioned concept hence, it is important to develop a comprehensive program for drought risk management in the event of severe and long-term droughts for each study area.