Kuntiyawichai et al. (2026) Combined drought index for drought monitoring and severity assessment under future climate and land use changes

Identification

• Journal: The Science of The Total Environment
• Year: 2026
• Date: 2026-03-20
• Authors: Kittiwet Kuntiyawichai, Sarayut Wongsasri, Wuttipong Kusonkhum, Bart Schultz, Prinya Chindaprasirt
• DOI: 10.1016/j.scitotenv.2026.181704

Research Groups

• Sustainable Infrastructure Research and Development Center, Khon Kaen University, Khon Kaen, Thailand
• IHE-Delft, Lelystad, the Netherlands

Short Summary

This study developed a Combined Drought Index (CDI) for the Prom-Choen-Upper Phong River Basin using Principal Component Analysis (PCA) of SPEI, SSFI, and SSDI to assess future drought risk under climate and land use changes. It found that while increased future rainfall may reduce overall drought risk, the SSP585 scenario significantly expands very high-risk drought areas, underscoring the need for the CDI in mitigation strategies.

Objective

• To derive a Combined Drought Index (CDI) for the Prom-Choen-Upper Phong River Basin based on Principal Component Analysis (PCA) of the Standardized Precipitation Evapotranspiration Index (SPEI), Standardized Streamflow Index (SSFI), and Standardized Water Supply-Demand Index (SSDI), and to use this CDI for drought monitoring and severity assessment under future climate and land use changes.

Study Configuration

• Spatial Scale: Prom-Choen-Upper Phong River Basin
• Temporal Scale:
  • Past/Present: 2000–2023 (drought index values), 2019 (land use baseline)
  • Future: 2024–2100 (drought index projections), 2075 (land use projections)

Methodology and Data

• Models used:
  • HEC-HMS
  • WEAP
  • Climate Models: CanESM5, MPI-ESM1-2-LR, NESM3 (for future climate projections)
• Data sources:
  • Future climate data under SSP245 and SSP585 scenarios
  • Future land use data
  • Standardized Precipitation Evapotranspiration Index (SPEI)
  • Standardized Streamflow Index (SSFI)
  • Standardized Water Supply-Demand Index (SSDI)
  • Principal Component Analysis (PCA) for CDI derivation

Main Results

• A Combined Drought Index (CDI) was successfully derived using Principal Component Analysis (PCA) of SPEI, SSFI, and SSDI.
• Future climate projections indicate increasing trends in mean annual rainfall and maximum/minimum annual average temperatures, with SSP585 showing greater increases and variability compared to SSP245.
• Future land use projections for 2075 (compared to 2019) show a significant decrease in paddy fields (158.3 km²) and an increase in urban areas (156.6 km²).
• Past extreme droughts were identified in 2005 and 2019–2020.
• Projected CDI values for 2024–2100 (SSP245: -0.14 to 0.89; SSP585: 0.05 to 0.36) are expected to increase compared to the 2000–2023 period (SSP245: -0.24; SSP585: -0.16), suggesting a potential shift towards more flooding rather than drought due to increased future rainfall.
• Drought hazard assessment using the CDI revealed very high-risk areas in most sub-districts within Khon Kaen and Chaiyaphum Provinces, with these areas projected to expand in the future, particularly under the SSP585 scenario.
• SSP245 leads to a slow increase in drought risk, whereas SSP585 vastly expands very high-risk areas.

Contributions

• Development of a novel Combined Drought Index (CDI) specifically tailored for the Prom-Choen-Upper Phong River Basin, integrating meteorological, hydrological, and water supply-demand aspects through PCA.
• Comprehensive assessment of future drought risk that accounts for both climate change (SSP245, SSP585 scenarios) and projected land use changes.
• Identification of specific high-risk drought areas and the differential impacts of various future climate scenarios on drought severity, providing a crucial tool for regional water resource management and mitigation strategies.

Funding

Not explicitly mentioned in the provided text.

Citation

@article{Kuntiyawichai2026Combined,
  author = {Kuntiyawichai, Kittiwet and Wongsasri, Sarayut and Kusonkhum, Wuttipong and Schultz, Bart and Chindaprasirt, Prinya},
  title = {Combined drought index for drought monitoring and severity assessment under future climate and land use changes},
  journal = {The Science of The Total Environment},
  year = {2026},
  doi = {10.1016/j.scitotenv.2026.181704},
  url = {https://doi.org/10.1016/j.scitotenv.2026.181704}
}