Estimating the long-term deformation and permanent loss of aquifer in the southern Junggar Basin, China, using InSAR

Abstract

Groundwater is the main water source for agricultural irrigation in arid/semi-arid agricultural region. Overexploitation of groundwater inevitably leads to permanent loss of aquifer and ground subsidence. The oasis agricultural area in the southern Junggar basin (JSOAA) is one of the largest oasis agricultural areas in western China. In this study, we, for the first time, recover the regional-scale ground displacements time-series of JSOAA, using all ALOS-1/PALSAR (2007–2010) and Sentinel-1 (2015–2020) data. The results show that there are multiple subsidence areas related to groundwater overexploitation. From 2007 to 2010, the area with a subsidence rate greater than 10 mm/yr is about 5876.2 km2, accounting for 13.2 % of the total area of JSOAA. From 2015 to 2020, these values are about 16146.7 km2 and 36.3 %. In the areas with concentrated groundwater exploitation, the small separate subsidence areas grew larger and became connected, and finally developed into giant subsidence clusters. The maximum cumulative deformation of JSOAA exceeded 400 mm from 2007 to 2010, and 500 mm from 2015 to 2020. We modeled the surface subsidence caused by the permanent aquifer loss, and estimated the volume strain of aquifer in JSOAA. The total volume strain of the aquifer is 2.73 km3 between 2007 and 2020. Moreover, we estimated the aquifer storage coefficient and the net groundwater deficit of JSOAA. The results of this study will serve for JSOAA aquifer health detection, ecological environment stability assessment, and sustainable development of the agricultural economy.