Abstract Hydrological droughts pose a severe threat to water security in semi-arid regions, especially under the influence of climate change. Understanding future drought dynamics is critical for informed planning and sustainable water resource management. This study evaluates hydrological drought susceptibility in an Indian semi-arid river basin using a conditional bivariate copula approach under changing climate scenarios. The Streamflow Drought Index (SDI), derived from Variable Infiltration Capacity (VIC) model-simulated streamflow, was analyzed for the historical period (1951–2000) and two future windows—Near Future (2001–2050) and Far Future (2051–2100)—using data from 13 downscaled and bias-corrected CMIP6 climate models. The analysis reveals a notable increase in drought severity (10–41%), duration (12–35%), and frequency (10–38%) under high-emission scenarios. Severe drought frequency in the most affected Dhasan Sub Basin (DSB) is projected to increase by 76% in the near future and 50% by far future under SSP585 with respect to the historical period. To capture the joint behavior of drought characteristics, four copula models (Clayton, Frank, Gumbel, and BB1) were employed, and joint return periods were computed. Severity-Duration-Frequency (SDF) curves were developed to quantify risk and assess changes in drought recurrence patterns. These findings highlight the need for region-specific drought mitigation through adaptive reservoir operations, resilient infrastructure, and early warning systems to reduce climate-related vulnerabilities. Research Highlights <UnorderedList Mark="Bullet"> <ItemContent> Seasonal streamflow is projected to decline, particularly in the pre-monsoon and winter seasons, increasing the risk of low-flow conditions under SSP370 and SSP585. </ItemContent> <ItemContent> Hydrological drought severity, duration, and frequency are expected to increase with the most significant rise underSSP585, especially in the Dhasan Sub-Basin. </ItemContent> <ItemContent> Sharp reduction in the frequency of compound extreme droughts, indicating higher drought risk in the future. </ItemContent> <ItemContent> Long or severe droughts significantly increases with higher emission scenarios. </ItemContent> </UnorderedList>

Evaluating hydrological drought characteristics in a semi-arid river basin using the conditional copula approach under the changing climate

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发表日期：

2026年3月12日

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Harsh Vardhan Singh,
Nitin Joshi,
Shakti Suryavanshi

摘要

Abstract

Hydrological droughts pose a severe threat to water security in semi-arid regions, especially under the influence of climate change. Understanding future drought dynamics is critical for informed planning and sustainable water resource management. This study evaluates hydrological drought susceptibility in an Indian semi-arid river basin using a conditional bivariate copula approach under changing climate scenarios. The Streamflow Drought Index (SDI), derived from Variable Infiltration Capacity (VIC) model-simulated streamflow, was analyzed for the historical period (1951–2000) and two future windows—Near Future (2001–2050) and Far Future (2051–2100)—using data from 13 downscaled and bias-corrected CMIP6 climate models. The analysis reveals a notable increase in drought severity (10–41%), duration (12–35%), and frequency (10–38%) under high-emission scenarios. Severe drought frequency in the most affected Dhasan Sub Basin (DSB) is projected to increase by 76% in the near future and 50% by far future under SSP585 with respect to the historical period. To capture the joint behavior of drought characteristics, four copula models (Clayton, Frank, Gumbel, and BB1) were employed, and joint return periods were computed. Severity-Duration-Frequency (SDF) curves were developed to quantify risk and assess changes in drought recurrence patterns. These findings highlight the need for region-specific drought mitigation through adaptive reservoir operations, resilient infrastructure, and early warning systems to reduce climate-related vulnerabilities.

Research Highlights

Seasonal streamflow is projected to decline, particularly in the pre-monsoon and winter seasons, increasing the risk of low-flow conditions under SSP370 and SSP585.

Hydrological drought severity, duration, and frequency are expected to increase with the most significant rise underSSP585, especially in the Dhasan Sub-Basin.

Sharp reduction in the frequency of compound extreme droughts, indicating higher drought risk in the future.

Long or severe droughts significantly increases with higher emission scenarios.