Insights into the Interconnected Dynamics of Groundwater Drought and InSAR-Derived Subsidence in the Marand Plain, Northwestern Iran

Groundwater drought, a significant natural disaster in arid and semi-arid regions, contributes to numerous consecutive issues. Due to the inherent complexity of groundwater flow systems, accurately quantifying and describing this phenomenon remains a challenging task. As a result of excessive agricultural development, the Marand Plain in northwestern Iran is experiencing both groundwater drought and land subsidence. The present study provides the first in-depth investigation into the intricate link between groundwater drought and subsidence. For this purpose, the open-source package LiCSBAS, integrated with the automated Sentinel-1 InSAR processor (COMET-LiCSAR), was utilized to assess land subsidence. The Standard Groundwater Index (SGI) was computed to quantify groundwater drought, aquifer characteristics, and human-induced disturbances in the hydrological system, using data collected from piezometric wells in a confined aquifer. The results revealed a negative deformation of 65 cm over a 75-month period, affecting an area of 57,412 hectares within the study area. The analysis showed that drought duration and severity significantly influence land subsidence, with longer and more severe droughts leading to greater subsidence, while more frequent drought periods are primarily associated with subsidence magnitude. Multi-resolution Wavelet Transform Coherence (WTC) analysis revealed significant correlations between groundwater drought and InSAR-derived land deformation in the 8–16-month period.