Buchupalle et al. (2026) Assessment of Compound Hydrological–Thermal Extremes over Indian River Systems

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Identification

• Journal: Water
• Year: 2026
• Date: 2026-04-09
• Authors: Jaya Bharat Reddy Buchupalle, Satish Kumar Mummidivarapu, Shaik Rehana, Shahid Latif, Taha B. M. J. Ouarda
• DOI: 10.3390/w18080896

Research Groups

Not explicitly mentioned in the provided text.

Short Summary

This study investigates the joint behavior of low river discharge (Q) and elevated river water temperatures (RWTs) in six Indian rivers, revealing significant spatial variability in compound hydrological and thermal extreme hazards and identifying suitable copula models for their assessment.

Objective

• To investigate the joint behaviour of river water temperatures (RWTs) and river discharge (Q) to assess compound extremes in six Indian rivers.

Study Configuration

• Spatial Scale: Six Indian rivers: Kaveri, Mahi, Sabarmati, Vardha, Bhadra, and Yamuna.
• Temporal Scale: Long-term analysis of extreme events, specific duration not provided.

Methodology and Data

• Models used: Weibull-3P distribution for river discharge (Q), Generalised Extreme Value (GEV-3P) distribution for river water temperatures (RWTs). Eighteen different parametric copula classes were evaluated, with Gaussian, Frank, and BB8 copulas identified as best fits for specific rivers.
• Data sources: River discharge (Q) and river water temperature (RWTs) data, likely from observations; specific sources not detailed.

Main Results

• The Weibull-3P and GEV-3P distributions were found to best fit river discharge (Q) and river water temperatures (RWTs), respectively.
• The Gaussian copula provided the best fit for the Vardha River, the Frank copula for the Bhadra River, and the BB8 copula for the Yamuna River.
• Significant spatial variability was identified in compound hydrological and thermal extreme hazards across the studied rivers.
• The semi-arid Vardha River exhibited the shortest joint return periods for simultaneous low Q and high RWTs, indicating a higher likelihood of combined extremes.
• The monsoon-fed Bhadra River displayed moderate hazard levels for these compound extremes.
• The Himalayan-fed Yamuna River showed the longest joint return periods and the lowest conditional probabilities, suggesting a lower likelihood of simultaneous extreme drought and heat events, though risks remain for less severe thresholds.

Contributions

• Addresses the limited exploration of bivariate water quality extremes (low river discharge and high river water temperatures) in river systems, particularly in an Indian context.
• Provides a robust methodology using copula models to assess compound hydrological and thermal extreme hazards.
• Identifies significant spatial variability in these hazards across diverse Indian river basins, offering crucial insights for region-specific water quality management and protection strategies.

Funding

Not explicitly mentioned in the provided text.

Citation

@article{Buchupalle2026Assessment,
  author = {Buchupalle, Jaya Bharat Reddy and Mummidivarapu, Satish Kumar and Rehana, Shaik and Latif, Shahid and Ouarda, Taha B. M. J.},
  title = {Assessment of Compound Hydrological–Thermal Extremes over Indian River Systems},
  journal = {Water},
  year = {2026},
  doi = {10.3390/w18080896},
  url = {https://doi.org/10.3390/w18080896}
}