EVALUATION OF GROUNDWATER STORAGE CHANGES USING SATELLITE GRAVIMETRY MISSION IN PENINSULAR MALAYSIA

Water stored beneath the Earth's surface, known as groundwater is a major water supply for living things. The increase in human population leading to high urban development and industrial needs in Malaysia has made the use of groundwater more critical. The current issue faced by Malaysia is the limitation of freshwater source from dam resulting in increasing demand to gather the source of fresh water from groundwater; hence, leading to the crucial exploitation of groundwater. Therefore, this study aims to evaluate groundwater storage (GWS) using Gravity Recovery and Climate Experiment (GRACE) and Global Land Data Assimilation System (GLDAS) data in Peninsular Malaysia. GRACE data consist information on the liquid water equivalent thickness covering terrestrial water storage (TWS) of GWS, soil moisture (SM), snow water equivalent (SWE), and surface water (SW). In comparison with GLDAS data, they only consist hydrological products of SM, SWE, and SW. Therefore, the differences between the GRACE and GLDAS data are most likely to reflect the information of GWS. Due to the seasonal monsoon, the changes in GWS can also be seen in specific months. In addition, the data can also be used to identify important areas that need improvement and attention. The output of this study is expected to help authorities monitoring the changes in GWS in recharge and discharge areas for future preservation of groundwater quality. Moreover, the excessive exploitation of groundwater can also be observed for the prevention of land hazard phenomena, such land subsidence.