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<p>Droughts are intensifying worldwide under climate variability, yet their regional dynamics remain poorly understood. This study provides the first century-scale (1902–2022) spatio-temporal assessment of meteorological droughts in the Mahanadi River Basin, India, using high-resolution (0.25° × 0.25°) gridded rainfall data, the Standardized Precipitation Index (SPI), and Mann–Kendall Trend (MKT) test. The results highlight that, (1) the escalating drought frequency as major short-term droughts (SPI-3) occurred in 1954, 1974, 1989, 1996, 2002, 2009, and 2017, while long-term droughts (SPI-12) were recorded in 1902, 1966, 1979, 1989, 2000, 2010, and 2016. Since 1954, the recurrence interval has shortened dramatically, with &gt; 30% of basin area affected during several events. Finding reveals, (2) the emerging drought hotspots as the middle basin faced the highest drought frequency (&gt; 4 events per 30&#xa0;years), with Chhattisgarh identified as the most vulnerable sub-region. (3) Rising severity of drought intensity regularly exceeded SPI ≤ –1.5 (severe) and reached SPI ≤ –2.0 (extreme) in recent decades, with drought extent peaking at ~ 35% of the basin. (4) Seasonal and multi-decadal shifts was observed before 1982, &gt; 30% drought coverage was restricted to pre-monsoon months; after 1982, nearly all months except May–June showed similar impacts. The humid subtropical (Cwa) zone endured persistent dry spells lasting 30–35&#xa0;years. (5) The outcome of MKT trend evolution detected statistically significant drying (90–99% confidence) from the 1930s onward, intensifying after 2010. Also, (6) anthropogenic amplification as land-use change, deforestation, and groundwater over-extraction further reduced hydrological resilience. By linking long-term climate variability with land-use pressures, this study reveals how historically water-secure regions are transitioning to drought hotspots. The findings provide a transferable framework for drought risk reduction in South Asia and other monsoon-dependent basins facing accelerated climate stress.</p>

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Spatio-Temporal Analysis of Drought Characteristics and Trend in Mahanadi River Basin Over the Last 121 years (1902–2022)

  • 期刊论文

  • 发表日期：

    2025年11月20日

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  • Preeti Rajput,
  • Manish Kumar Sinha,
  • Ajay Kumar Garg,
  • Mukesh Kumar Verma

摘要

Droughts are intensifying worldwide under climate variability, yet their regional dynamics remain poorly understood. This study provides the first century-scale (1902–2022) spatio-temporal assessment of meteorological droughts in the Mahanadi River Basin, India, using high-resolution (0.25° × 0.25°) gridded rainfall data, the Standardized Precipitation Index (SPI), and Mann–Kendall Trend (MKT) test. The results highlight that, (1) the escalating drought frequency as major short-term droughts (SPI-3) occurred in 1954, 1974, 1989, 1996, 2002, 2009, and 2017, while long-term droughts (SPI-12) were recorded in 1902, 1966, 1979, 1989, 2000, 2010, and 2016. Since 1954, the recurrence interval has shortened dramatically, with > 30% of basin area affected during several events. Finding reveals, (2) the emerging drought hotspots as the middle basin faced the highest drought frequency (> 4 events per 30 years), with Chhattisgarh identified as the most vulnerable sub-region. (3) Rising severity of drought intensity regularly exceeded SPI ≤ –1.5 (severe) and reached SPI ≤ –2.0 (extreme) in recent decades, with drought extent peaking at ~ 35% of the basin. (4) Seasonal and multi-decadal shifts was observed before 1982, > 30% drought coverage was restricted to pre-monsoon months; after 1982, nearly all months except May–June showed similar impacts. The humid subtropical (Cwa) zone endured persistent dry spells lasting 30–35 years. (5) The outcome of MKT trend evolution detected statistically significant drying (90–99% confidence) from the 1930s onward, intensifying after 2010. Also, (6) anthropogenic amplification as land-use change, deforestation, and groundwater over-extraction further reduced hydrological resilience. By linking long-term climate variability with land-use pressures, this study reveals how historically water-secure regions are transitioning to drought hotspots. The findings provide a transferable framework for drought risk reduction in South Asia and other monsoon-dependent basins facing accelerated climate stress.