Role of catchment and climate characteristics in Hydrological Drought parameters and propagation in major river basins of India

The understanding of the propagation of meteorological droughts to hydrological droughts is an important phenomenon to take pre-emptive action to mitigate the effects of droughts. In this study, we have correlated the Standardized Streamflow Index (SSI) with the Standardized Precipitation Index (SPI-n) for 224 stations across India to analyze drought propagation time, which is specific to each catchment. Results indicate higher propagation times for basins lying in arid and semi-arid climate regions whereas lower propagation time is found for basins lying in wetter climate regions. The run theory is applied to SSI to identify all streamflow drought events for each station and the optimal Hydrological Drought Instantaneous Development (IDS) and Instantaneous Recovery Speeds (IRS) are calculated along with parameters; duration and severity. Drought propagation speeds can be used to simulate drought duration and severity for a catchment. Simulated drought duration for various catchments shows good agreement (R² > 0.7) with observed drought duration, therefore calculated optimal IDS and IRS can be used in forecasting drought conditions for each catchment. The effect of catchment characteristics on drought parameters was evaluated statistically by using heatmaps and bivariate correlation. This study provides comprehensive catchment-specific drought analysis for all major basins of India, which can be used by water managers to promptly and effectively avert drought and related disasters.