TERRESTRIAL WATER STORAGE INFERRED FROM SATELLITE GRAVITY DATA

Abstract

Lately, various investigations have demonstrated that climatic change is probably going to affect the freshwater accessibility. In India, demand for the fresh-water has increased rapidly throughout the years because of urbanization, agricultural extension, population outburst, fast industrialization and financial advancement. This has led to over-misuse of fresh- water which has led to variations in the hydrological cycle. Total water storage (TWS) is one of the parameters to quantify water accessibility in a region. It can be easily calculated using air-borne satellites. Ground water storage monitoring is tedious and very time consuming due to variability of type of aquifers in different regions and accessibility to well data. Previous studies have shown a steady decline in ground-water storage in Uttarakhand region whereas only a few studies have been focussed on ground-water sustainability in this region. This research is an attempt to highlight the issue of declining groundwater levels in Uttarakhand using satellite gravimetry data (GRACE). In this study we calculated the TWS over Uttarakhand region and found declining trend of TWS in this region from 2002-16. To validate the trend of TWS in Uttarakhand, TWS trends in 5 districts of Uttarakhand region were generated using GRACE data and compared with the trend of ground water level in the 5 districts using dug-well data provided by CGWB in the region. The trend calculated from GRACE data shows good correlation with the ground-water data from the dug-wells, which validates the declining trend of TWS in Uttarakhand found using GRACE data.