[AHW30-P03] Dynamics of terrestrial water storage in three major river basins over Peninsular India
キーワード：GRACE, Terrestrial Water Storage, Peninsular India
Synergic impacts of natural and anthropogenic factors such as climate variability and excessive water consumption have led an unprecedented stress on the global water resources with higher concern for the developing nations. Peninsular Indian region has been highlighted as highly non-resilient to hydrological extremes such as droughts. Three major river basins namely, Mahanadi, Krishna, and Godavari having a combined geographical area share of 22 % of the total geographical area of India, and almost similar hydrogeological conditions were selected for the long term assessment of the terrestrial water storage (TWS) dynamics. Five gravity anomaly solutions (two mascon based products and three spherical harmonic based products) from different data processing centers were accessed and processed to get equivalent water thickness and subsequently utilized for understanding the TWS dynamics in terms of the relative anomaly. Generalized three-cornered hat (GTCH) method was employed to get the combined TWS data series corresponding to the minimum uncertainties. The resulting anomaly series showed a piecewise TWS trend of -1.21mm yr-1 and -18.81 mm yr-1 from April 2002 to June 2010 and July 2010 to May 2017 respectively in Mahanadi basin. The piecewise TWS trends in Krishna and Godavari basins are -12.55 and -4.45 from April 2002 to June 2010, and -30.95 and -10.41 mm yr-1 from July 2010 to May 2017, respectively. Despite the different patterns of trends until June 2010, all three basins are showed a high rate of decline in TWS (volume equivalent of 18.17, 54.53, 21.75 km3, respectively) thereafter. These declining trends of TWS highlight the need of the conjunctive water management strategies, and policymaking in the region for achieving a sustainable and efficient water use at the basin scales.