Homdee et al. (2026) Robust Streamflow and Drought-Flood Hazard Signals from Criteria-Based Verification of Hybrid Hydrological Projections Under Climate and Land-Use Change

⚠️ Warning: This summary was generated from the abstract only, as the full text was not available.

Identification

• Journal: Water
• Year: 2026
• Date: 2026-11-05
• Authors: Tipaporn Homdee, Kowit Boonrawd, Rattana Hormwichian, Haris Prasanchum
• DOI: 10.3390/w18212759

Research Groups

Not explicitly stated in the provided text, but likely involves institutions in Northeast Thailand focusing on hydrology, climate change, and land-use planning.

Short Summary

This study developed a hybrid QSWAT-ANN workflow with a four-criteria verification system to assess the robustness of streamflow projections under climate and land-use change in the Huai Luang River Basin, Thailand. It found that signal direction, seasonal structure, and upper-tier spatial cores of projections were robust for management, while absolute index magnitudes were not.

Objective

• To develop and apply a hybrid QSWAT-ANN workflow with a built-in four-criteria verification system to identify which streamflow projection results are robust to model uncertainty under climate and land-use change in the Huai Luang River Basin.

Study Configuration

• Spatial Scale: Huai Luang River Basin (HLRB) in Northeast Thailand, including 31 sub-basins.
• Temporal Scale: Projections to 2070.

Methodology and Data

• Models used: Hybrid QSWAT-ANN workflow.
• Data sources: Six CMIP6 trajectories (three climate models under SSP2-4.5 and SSP5-8.5 scenarios), and a single land-use pathway.

Main Results

• The corrected model passed performance criterion (C1) with overall Nash-Sutcliffe Efficiency (NSE) values of 0.80 and 0.79.
• Ensemble precipitation increases of 10.5–13.7% were amplified into annual streamflow increases of 32.0–49.9%, concentrated in the monsoon season.
• Paddy rice cultivation is projected to decrease by 55.1% towards cash crops.
• Within-trajectory Standardized Streamflow Index (SSFI) signals agreed in direction in at least four of six trajectories in all cases (C2 passed), with ACCESS-CM2 being the only dissenting trajectory.
• Spatial ranking agreement (C3) for Drought Hazard Index (DHI) and Flood Hazard Index (FHI) classifications of 31 sub-basins showed Spearman correlation coefficients (p) of 0.545–0.646 and 0.570–0.811, respectively, passing the 0.60 threshold in three of six cases.
• Robust cores of eight (DHI) and ten (FHI) sub-basins were identified with agreement in at least five of six trajectories.
• Reference-series sensitivity (C4) confirmed complete rank preservation (p = 1.000), while index magnitudes shifted by typically 1.2–1.5 standard deviations (SD) and more than 7 SD in extreme drought months.
• The workflow identified signal direction, seasonal structure, and upper-tier spatial cores as robust enough for Huai Luang reservoir management and sub-basin drought and flood targeting, but absolute index magnitudes should not be used as design values.

Contributions

• Developed a novel hybrid QSWAT-ANN workflow incorporating a built-in four-criteria verification system to systematically assess the robustness of streamflow projections.
• Provided a practical framework for identifying reliable aspects of climate and land-use change impacts on streamflow, specifically distinguishing between robust and non-robust projection components.
• Offered actionable insights for water resource management in monsoon basins, indicating which projection elements (e.g., signal direction, spatial patterns) are suitable for decision-making versus those requiring caution (e.g., absolute magnitudes).
• Demonstrated the transferability of the developed framework to other monsoon basins.

Funding

Not explicitly stated in the provided text.

Citation

@article{Homdee2026Robust,
  author = {Homdee, Tipaporn and Boonrawd, Kowit and Hormwichian, Rattana and Prasanchum, Haris},
  title = {Robust Streamflow and Drought-Flood Hazard Signals from Criteria-Based Verification of Hybrid Hydrological Projections Under Climate and Land-Use Change},
  journal = {Water},
  year = {2026},
  doi = {10.3390/w18212759},
  url = {https://doi.org/10.3390/w18212759}
}