A research on water storage changes in the Indus-Ganges river basin based on GRACE time-varying gravity field

The Indus and Ganges rivers are important rivers in Asia,and the two basins the two rivers passed are also the most populous areas in Indian subcontinent.It is of great significance to study the water storage changes in this region to ensure the local ecological environment and economic development.In this paper, the GRACE_RL05 Time-varying gravity field model was used to calculate the change of total water storages of Indus-Ganges River Basin from 2002s to 2016s,and the GLDAS hydrological model was used to calculate the changes of groundwater storages.The study found that,the Total Water Storages (TWS) and Groundwater Water Storages (GWS) of the Indus and Ganges showed a downward trend from 2002s to 2016,and the rate of groundwater decline (respectively-7.2 mm／year and-4.7 mm／year) in both basins exceeded the TWS decline rate.Comprehensive hydrological model data analysis shows that the reason for the decline in water reserves in this area is caused by excessive pumping pipelines in excessive agricultural irrigation against the background of rising evaporation and continuous reduction of precipitation.