Drought and flood dynamics of Godavari basin, India: A geospatial perspective

Assessing incidence and trends of droughts and floods can provide essential information for better water resource management, particularly in the context of ongoing climate change. The present study has examined the prevalence of drought and flood events of Godavari basin, India, for the last four decades using the Standardized Precipitation Evapotranspiration Index (SPEI) 3 months and 9 months, and their trends using Mann–Kendall’s test and Sen’s slope. The spatial distribution, frequency, and intensity of drought and flood episodes in the basin are not uniform. A 20-year breakdown, 1980–1999 and 2000–2019, shows a drastic increase in drought frequency in Manjra and Pranhita sub-basins, while Godavari Upper, Indravati, and northern part of Weinganga have registered increased flood frequency. The monthly trend of SPEI-3 shows that most of the sub-basins have registered a negative trend (increasing dryness) only during the winter months, while under the SPEI-9 scenario both Manjra and Pranhita registered strong negative trend throughout the year. Sen’s slope estimations detected an increasing trend in severity from SPEI-3 to SPEI-9. Dryness severity trend is highest in Pranhita, followed by Manjra, Wardah, and Lower Godavari sub-basins, and the increasing wetness severity trend is in Upper Godavari, while rest of the sub-basins do not show any significant trend. The interior districts of the basin are more prone to the high drought conditions in near future if the current trends persist. To sustain the future climate change challenges, the vulnerable districts need urgent structural and non-structural changes in their current water resource management practices.