Integrated study of GRACE data derived interannual groundwater storage variability over water stressed Indian regions

Abstract

Groundwater serves more than 80% of agriculture and 60% of drinking water in India thus making it a demandable resource in the study area. In this study the groundwater storage change was determined by using RL05 land data product (January, 2003 to December, 2016) which was accessed from the Gravity Recovery and Climate Experiment (GRACE) satellite. Total soil moisture (up to 2m depth), canopy water storage and snow water equivalent derived from Global Land Data Assimilation System (GLDAS) NOAH was subtracted from terrestrial water storage (TWS) for extracting the groundwater component, revealing maximum groundwater storage change by −7.52 cm/year in Delhi, northern Uttar Pradesh and some parts of Haryana. In water stressed regions of India (January 2003 to December 2016) the groundwater depletion rate in the cities of Delhi, Meerut, Dehradun and Chandigarh are −3.682 ± 0.8 cm/year, −3.62 ± 0.7 cm/year, −3.1 ± 0.87 cm/year, −2.73 ± 0.6 cm/year respectively. The groundwater storage change (GWSC) depletion rate observed in Delhi, Meerut, Dehradun, Chandigarh in January 2003 to May 2010 are −3.43 ± 1.37, −3.41 ± 1.22, −3.72 ± 1.52, −3.43 ± 1.05 cm/year respectively and in August 2010 to December 2016 depletion rate is −5.53 ± 1.57, −7.12 ± 1.40, −4.98 ± 1.74,-3.92 ± 1.20 cm/year respectively. The data obtained by GRACE/GLDAS-derived total GWS (cm) and Global Positioning System (GPS)-derived vertical deformation of International GNSS services (IGS) station, at Indian Institute of Science (IISc) Bangalore (2014–2016) is correlated by 0.71. Analysis conducted in metro cities (Delhi, Chennai, Bengaluru, Kolkata and Mumbai) shows with time succession groundwater storage has suffered a major depletion in spite of quantified rainfall in these places. The GRACE-derived GWSC values agrees reasonably with in-situ well observations by Pearson's coefficient; 0.89, 0.88, 0.87 and 0.74 for Delhi, Haryana, Punjab and Uttar Pradesh thereby justifying remote sensing approach and further substantiate our research study that regional GWS mapping can be achieved by the GRACE mission rapidly and accurately.