Evaluation of Land Subsidence in Abarkooh Plain Using Radar Differential Interferometry Technique And GIS

Land subsidence is a vertical movement downwards of the Earth's surface. It is difficult to identify or measure because of rapidly depleting ground water. This hazard, as a hydrogeomorphology phenomenon, is revealed in many areas of the country because of the uncontrolled depletion of the groundwater. There are a number of methods for identifying and determining the rate and range of subsidence. Radar interferometry (D-INSAR) technique is known as a robust technique for land subsidence measurement. This method has superior features in terms of cost, accuracy, scale of the study area and time, in comparison with other detection methods, and can provide a precise estimation of the phenomenon. In this study, the Abarkouh plain was studied from January 2016 until February 2018. Sentinel 1 sensor images using radar interferometry technique were used to estimate subsidence. To identify the impact of groundwater extraction in land subsidence, groundwater fluctuations data from 44 piezometric wells, and also land subsidence data were analyzed using regression models. Results showed that the highest rate of groundwater depletion occurred in the town of Mehrdasht and around the agricultural fields, which led to the maximum rate of subsidence up to 12 cm/year. Ccorrelations coefficient between aquifer fluctuations and land subsidence rate is 0.79 that indicated significant relation between these parameters.