Nair et al. (2026) Assessing climate change effects on streamflow and paddy production in the Bharathapuzha Basin Kerala

Identification

• Journal: Scientific Reports
• Year: 2026
• Date: 2026-05-07
• Authors: Gulja S. Nair, D. Karunanidhi, Berihu Abadi Berhe
• DOI: 10.1038/s41598-026-52356-3

Research Groups

• Department of Agricultural Engineering, Nehru Institute of Technology, Coimbatore, India
• Department of Civil Engineering, School of Engineering, Mohan Babu University, Tirupati, India
• School of Earth Sciences, College of Natural and Computational Sciences, Mekelle University, Ethiopia

Short Summary

This study evaluates the impact of climate change on streamflow and paddy yields in the Bharathapuzha Basin, Kerala, using SWAT and CMIP6 models, predicting significant declines in crop production and altered hydrological regimes by 2100.

Objective

• To examine how climate variations and projections affect hydrological processes (specifically streamflow) and paddy yield in the Bharathapuzha River watershed.

Study Configuration

• Spatial Scale: Bharathapuzha River watershed, Kerala, India (with specific analysis of the Palakkad and Alathur blocks).
• Temporal Scale: Projections extending to the year 2100, with specific analysis for the near-term (2035) and late-century periods.

Methodology and Data

• Models used: Soil and Water Assessment Tool (SWAT) for hydrological and yield simulation; three CMIP6 climate models under two Shared Socioeconomic Pathways (SSPs).
• Data sources: Observed streamflow data, district-level paddy yield statistics, and CMIP6 climate projection data.

Main Results

• Hydrological Impact: Increased rainfall variability and temperature are projected to cause intensified flood peaks and heightened water stress during dry seasons.
• Paddy Yield Decline: Under the SSP5-8.5 scenario, paddy yields are projected to decrease by 23–33% by 2035 and by 68–74% by 2100.
• Regional Sensitivity: The Alathur block exhibits higher sensitivity in the near term, whereas the Palakkad block faces more severe declines toward the end of the century.
• Model Validation: The SWAT model demonstrated good performance with a Nash-Sutcliffe Efficiency (NSE) of 0.74 for monthly streamflow, 0.80 for paddy yield in Palakkad, and 0.68 in Alathur.

Contributions

• Quantifies the long-term vulnerability of Kerala's paddy cultivation to climate change, providing a scientific basis for implementing adaptive measures such as climate-resilient crop varieties, optimized planting schedules, and enhanced irrigation management to safeguard regional food security.

Funding

• This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Citation

@article{Nair2026Assessing,
  author = {Nair, Gulja S. and Karunanidhi, D. and Berhe, Berihu Abadi},
  title = {Assessing climate change effects on streamflow and paddy production in the Bharathapuzha Basin Kerala},
  journal = {Scientific Reports},
  year = {2026},
  doi = {10.1038/s41598-026-52356-3},
  url = {https://doi.org/10.1038/s41598-026-52356-3}
}