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

Abstract

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. Supplementary Information The online version contains supplementary material available at 10.1007/s12517-022-10041-5.

The Monsoon's Influence on Central Asia's Subsequent Periods of Drought and Flooding

“…The Theory of Runs is recognized as one of the most effective methods for analyzing time series and has been applied in numerous hydrological and meteorological studies (Freinkman & Yossifov, 2012; Razmkhah, 2017). This method adequately identifies drought and flood events by estimating the average drought length over the desired time period and studying their properties for their characteristics (Sarkar, 2022b; L. Wang et al., 2020). Runs denote a series of the same phenomena that satisfy certain threshold level, and this level helps to identify the beginning, continuation, or end of dry and wet events.…”

“…Dry and wet duration (d) denotes the period from the beginning to the end of the dry or wet event. The severity, intensity, and frequency of both dry and wet events over the study area were defined by Equations 1-3: Based on the duration extent, the cumulative sum of the SPEI ≤ 1 or SPEI ≥1.0 values determines the Severity (S) for a dry or wet condition, respectively (Equation 1) (Sarkar, 2022a).…”

“…The Intensity (I) of a drought event is the ratio of its severity to its duration, and vice versa for a flood (Equation 2) (Sarkar, 2022a). Events with a shorter duration and higher severity will have larger intensities.…”

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“…Insufficient sowing, delayed planting, and poor crop growth due to lack of soil moisture result in decreased yields, significantly impacting livelihoods [48]. Around 53% of India's agriculture depends on rainfall, making droughts a major issue for the country's rain-reliant farmers and causing severe water crises [49]. Drought is anticipated to worsen due to predicted climate change, leading to an expansion in droughtaffected areas.…”

Flood Risk Assessment for an Irrigation Project in Odissa, India

“…Flooding can inflict severe damage to irrigation systems, leading to reduced agricultural productivity, economic losses, and food security challenges (2,3) . To address these multifaceted issues effectively, a systematic and integrated approach to flood risk assessment and mitigation is imperative (4,5) . Flood modeling is an indispensable tool https://www.indjst.org/ in the planning and implementation of irrigation projects.…”