Regional analysis of drought severity‐duration‐frequency and severity‐area‐frequency curves in the Godavari River Basin, India

Abstract

India is one of the most drought‐ravaged countries in the world and faces at least one drought in one region or another in every 3 years. There is no single reliable approach in characterizing future droughts. To understand future drought risk, potential changes of drought properties and characteristics are analysed in this study. Using Fuzzy c‐means clustering approach, homogeneous drought regions are identified in the Godavari river basin and therefore, optimum number of clusters were assigned as four. The 12‐month standardized precipitation index (SPI) using precipitation data from India Meteorological Department (IMD) and Global Climate Model (GCM)—MIROC‐ESM‐CHEM is calculated for the homogeneous regions of the Godavari basin. The best fit copula for observed and simulated severity and duration are: Region 1—Clayton, Regions 2 and 3—Gumbel, Region 4—Frank copula. Severity‐duration‐frequency (SDF) and severity‐area‐frequency (SAF) curves were developed and analysed using the best fit copulas. The research findings conclude that moderate and severe droughts are frequently increasing for future periods (2006–2099) compared to the historic period (1962–2005). Droughts with high severity and high mean interarrival time are observed as expected in the future. For the Godavari basin, the SDF curves were concave upwards indicating an increase in severity with an increase in duration. The rate of increase of severity is small for shorter durations compared to that of longer‐duration drought. Thus, more prolonged drought events in the 21st century are likely to occur. The SAF curves with steeper slopes and high variability in topographical and hydrological characteristics have been observed over the Godavari basin. From these curves, for a specified percentage of area and return period, the drought severity can be calculated and the information can be used for crop management and agricultural water demands. Overall, the findings of this research offer a view of likely scenarios of drought in the Godavari basin.

Streamflow drought onset and severity explained by non‐linear responses between climate‐catchment and land surface processes

“…Further, we detected a strong non-linear relationship between drought onset time and the deficit volume in monsoon-dominated catchments, which is often not assessed in earlier assessments. The methodology presented here and potential environmental controls can serve as a basis for climate change impact assessments and aid in multivariate frequency analysis of droughts, especially in regional contexts (Kumar et al, 2021), enhancing operational drought forecasts across river basins, especially in places where seasonality dominates streamflow variability. Our assessment emphasizes that environmental controls play a crucial role in understanding the severity of drought.…”

Bridging the Data Gap between the GRACE Missions and Assessment of Groundwater Storage Variations for Telangana State, India

“…However, the groundwater availability of the study area is rather uneven, with aquifers ranging from crystalline to sedimentary aquifers [1]. Moreover, due to the uneven distribution of rainfall because of climate change, groundwater usage has increased tenfold in different parts of the country [8][9][10].…”

Stepwise cluster ensemble downscaling for drought projection under climate change

“…Some studies showed that drought duration and occurrence are likely to increase for many regions in the future based on outputs from RCM/GCM (Touma et al ., 2015; Gu et al ., 2019; Huang and Fan, 2021). For instance, Kumar et al calculated 12‐month SPI index over the Godavari basin using MIROC‐ESM‐CHEM global climate model data for the three future simulations trying to understand future drought risk (Kumar et al ., 2021). They found that droughts in India may increase both in intensity and duration in the future.…”