Multivariate drought analysis for the temperature homogeneous regions of India: Lessons from the Gomati River basin

Droughts inflict significant loss on agricultural economies. Gomati River basin, the area of the present study, is located within the Ganga River floodplains, which approximately coincide with the north central temperature homogeneous region (NCTHR) of India. Gomati basin is a non-perennial one supporting water intensive agricultural crops. To ascertain the occurrence of droughts (if any) from 1986 to 2015 within Gomati River basin, in terms of inter-dependencies of drought causing variables through study of multivariate drought indices, is the main objective of the present study. Soil Water Assessment Tool (SWAT) was used in combination with the Copula approach to construct multivariate standardized drought indices (MSDIs) for drought onset detection through simulation in the face of data scarcity. Although MSDI based assessment of the basin as a whole did not detect any droughts, in the upper basin, MSDIs indicated the possibilities of impending agricultural droughts marked by their consistent variability around near-normal conditions. This methodology can be used to detect drought situations in data scarce non-perennial river basins within the Ganga River floodplains including the NCTHR of India.