Investigation of land subsidence due to groundwater withdraw in Rafsanjan plain using GIS software

Nowadays, the purpose of predicting land subsidence is to manage the optimum usage of groundwater, which is considered according to irregular use of groundwater. Digging deep and semi-deep wells and continuous drought, mainly in wasteland and semi-wasteland zone in recent years causes the land subsidence in Rafsanjan plain. The Rafsanjan basin is located in the nearly central part of Iran in the Kerman province, with a general elevation between 1,400–1,500 m above sea level. In this research, first, the deep and semi-deep wells were investigated and groundwater table data were colleted. Second, these informations were analyzed and corrected. These data were used to create great bank of information data, to manage and program the geographic information system (GIS) software. Then by investigation of an existing land subsidence data, which were collected by GPS in August 1998 and April 1999, by the GIS software, the results show that discharging of groundwater is the main factor of the land subsidence in Rafsanjan zone. Therefore, the critical land subsidence zone of the Rafsanjan plain was determined, and precaution and recommendations are presented.