Temporal Analysis of Land Subsidence and Groundwater Depletion Using the DInSAR and Kriging Methods: A Case Study and Insights

Abstract

In recent years, rising demands for water resources have led to extensive groundwater exploitation, particularly in arid and semiarid regions, triggering land subsidence. The Arak Plain, located in Iran’s Markazi Province, a vital area for agriculture and industry, has recently faced significant subsidence due to excessive groundwater extraction. This study investigates the correlation between land subsidence and declining groundwater levels in this plain. To assess land subsidence, the differential interferometry synthetic aperture radar (DInSAR) method was employed, utilizing high-accuracy Sentinel 1 IW SLC C-band products. The analysis was conducted using the SNAP open-source software from 2016 to 2021. Groundwater level declines from 2005 to 2021 were determined using universal kriging with an exponential semivariogram. Subsequently, a comparison between subsidence rates and piezometric levels was conducted. The analysis revealed continuous increase in the rate and extent of subsidence over time, with the highest annual subsidence occurring in 2020 (9 cm/year) and extensive subsidence at a rate of approximately 5.5 cm/year in most areas of the plain in 2021. Additionally, the southern and southwestern regions of the Mighan Playa exhibit remarkable subsidence due to groundwater level declines. This distinctive subsidence pattern results from geological structure and specific environmental conditions. The findings of this research demonstrate that, while excessive groundwater extraction is not the sole cause of subsidence, it remains one of the primary contributing factors. In light of these results, urgent implementation of effective measures is crucial for the long-term sustainable management of groundwater resources in the Arak Plain. In arid and semiarid regions, the growing demand for water resources has resulted in excessive groundwater extraction, leading to land subsidence. This poses significant risks to above-ground and underground infrastructure, such as buildings, railways, and utility lines. The Arak Plain, in Iran’s Markazi Province, a key area for agriculture and industry, has experienced notable subsidence due to excessive groundwater extraction. This study employs remote sensing, a technical method for assessing subsidence, using open-source software from 2016 to 2021. The decline in groundwater levels from 2006 to 2021 was determined, and a comparison of subsidence rates and groundwater levels was conducted. The analysis revealed a continuous increase in the rate and extent of subsidence over time. The highest annual subsidence occurred in 2020 (9 cm/year), with most areas of the plain experiencing significant subsidence at a rate of approximately 5.5 cm/year in 2021. This research highlights that, while excessive groundwater extraction is not the sole driver of subsidence, it is a significant contributing factor. These findings emphasize the importance of implementing effective measures for sustainable management of groundwater resources in the Arak Plain.