Characterization of Irreversible Land Subsidence in the Yazd-Ardakan Plain, Iran From 2003 to 2020 InSAR Time Series

Groundwater extraction rates exceeding recharge are occurring throughout Iran to sustain industrial and agricultural activities, resulting in land deformation in many areas, particularly in the Yazd-Ardakan Plain (YAP) in central Iran's dry and desert regions. In this study, Interferometric Synthetic Aperture Radar (InSAR) time series analysis and statistical models are applied to characterize the controls on land subsidence in the YAP from 2003 to 2020. Our results reveal the existence of a northwest-southeast elongated area of 234.45 km(2) experiencing subsidence at rates up to 15 cm/yr. In the YAP, the international Airport, railway, transit road, and several industrial and historical sites are threatened by the differential subsidence. Well data confirm that groundwater levels have decreased by 18 meters between 1974 and 2018, driving the compaction of sediments within the underlying aquifer system. Our statistical analysis shows that the thickness of a shallow, clay-rich aquitard layer controls the extent of the observed subsidence and the Independent Component Analysis of the InSAR time series shows that inelastic compaction is dominated. This work reveals that current groundwater extraction practices in central Iran are not sustainable and result in permanent subsidence, ground fractures with impact on infrastructures, and a permanent decrease in water storage capacity. Plain Language Summary As the world's population grows, the pressure on finite water resources intensifies, especially in desert areas around the world. Groundwater extraction is often accompanied by many ancillary problems such as land subsidence. In this work, we show that the measurements of such land subsidence from satellites can be used to inform many aspects of water sustainability management plans, which are necessary to develop and implement in the YazdArdakan Plain (YAP) of Central Iran. Between 2003 and 2020, our ground deformation data in this area highlight (a) subsidence up to 15 cm/yr, (b) damage to several strategic infrastructures, (c) a significant yearly groundwater storage loss, and (d) the controls on the land subsidence. This work reveals that permanent, irrecoverable compaction dominates, mostly controlled by sediments in the subsurface, and reveals that the current groundwater extraction practices in central Iran are not sustainable. This work is complementary to the previous studies, providing essential and important data to investigate the possibility of the collapse of the surface layer and the distribution of fractures in the YAP.