Investigating InSAR-derived land motion due to aquifer compaction in the northeast regions of Haryana, India

Rapid urbanization and agricultural activities increase the dependency on groundwater (GW)  creating stress on aquifer systems in India. In Northern India, states like Haryana, Punjab, Delhi, and Rajasthan are facing acute freshwater crisis. The agrarian state, Haryana, which lies in the upper Yamuna and Ghaggar river basins with recent alluvial deposits of Indus alluvial plains, has a vast area under paddy cultivation. In particular, Kaithal, Karnal and Kurukshetra districts of Haryana are known for their highest rice cultivation which is continuous since 1970s. Although, Ghaggar and Markanda are the major seasonal rivers, groundwater is the largest source of irrigation in these district. The continuous use of groundwater results in sharp decline of water table. Farmers are using tubewell water instead of canal water due to less labor force and due to technology enhancement. Farmers are using deep tubewells to extract water and most of them have installed underground pipelines in the fields for irrigation. According to Haryana Water Resource Authority (HWRA), most of the villages of these districts are currently falling in the dangerous category of GW decline i.e., “Red Zone” means water level has  been declined more than 40 meters below ground level (mbgl). As per the Central Ground Water Board (CGWB) report, analyzing  monitoring wells depicts decline of water level from 10 to 30 mbgl from 2001 to 2021. So, lack of continuous monitoring mechanisms for investigating the groundwater system may create severe consequences of this high depletion rate and local scale subsidence. This study focused on the understanding of the line of sight (LOS) velocity map and hydraulic head level change over Kurukshetra, Kaithal and Karnal districts. We explore the ascending Synthetic Aperture Radar (SAR) data of the Sentinel-1 A/B sensor of the European Space Agency (ESA) with 183 acquisitions from 2016 to 2022 using path and frame numbers 27 and 91, respectively. We have processed sub swath F2. For the SAR data processing, we used the multi-temporal Interferometric Synthetic Aperture Radar (MT-InSAR) technique using an open-source tool, “GMTSAR-SBAS” by Sandwell et al. (2011). The reference image dated 09 January 2020 is used, and a Digital Elevation Modal (DEM) of Shuttle Radar Topographic Mission (SRTM3) with a spatial resolution of 90m used for topographic removal. Baseline thresholds of 60 (days) & 150 (meters) were used to generate 592 suitable interferograms for velocity and displacement time-series generation.

The unwrapping of interferograms was processed with Snaphu method, and interferograms were used to generate the Velocity time map. Small Baseline Subset (SBAS) analysis was performed for phase inversion and correction. As per the preliminary InSAR-derived LOS Velocity Map studies, these districts show a land movement ranging from -2 to more than -10 mm/year. InSAR-derived results show land motion of more than -10 mm/year in Kaithal,  -4 mm/year in Kurukshetra and -2 to -4 mm/year in Karnal. The preliminary analysis of Panipat district showed land movement of ~ 2 mm/year towards satellite.

The study will help for an effective water management plan and consequences of over-exploitation of groundwater in  Haryana.