Lee et al. (2026) Satellite- and Ground-Soil-Moisture Synchronization and Rainfall Index Linkage for Developing Early-Warning Thresholds for Flash Floods in Korean Dam Basins

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Identification

• Journal: Water
• Year: 2026
• Date: 2026-04-10
• Authors: Jaehoon Lee, Jeong-Seok Yang
• DOI: 10.3390/w18080909

Research Groups

Not explicitly available in the provided text.

Short Summary

This study developed a Random Forest model to generate continuous, daily basin-representative soil moisture by integrating various hydro-meteorological data in South Korean dam basins, demonstrating that antecedent wetness significantly influences rapid discharge events and deriving effective composite thresholds for flash-flood early warnings.

Objective

• To integrate diverse hydro-meteorological data to generate continuous, daily basin-representative soil moisture, quantify the relationships among precipitation, basin wetness, and rapid discharge increases, and derive composite thresholds for flood early warnings in South Korean dam basins.

Study Configuration

• Spatial Scale: 26 standard basins (SBs) within three dam basin regions in South Korea: the Nam River Dam (NGD) and the upstream and downstream regions of the Seomjin River Dam (SJD).
• Temporal Scale: 2018 to 2024 (6 years), with daily resolution for the estimated soil moisture series.

Methodology and Data

• Models used: Random Forest regression model.
• Data sources: Satellite-soil-moisture observations, ground-soil-moisture observations, hydro-meteorological variables (1-day accumulated precipitation, 7-day accumulated precipitation, antecedent precipitation index, and related meteorological variables), and observed streamflow data.

Main Results

• The Random Forest model successfully estimated continuous, daily basin-representative soil moisture (SM_RF) with a coefficient of determination (R²) ranging from 0.6 to 0.7 for most standard basins.
• Extreme event days were consistently associated with elevated values of SM_RF, 1-day accumulated precipitation, 7-day accumulated precipitation, and the antecedent precipitation index, confirming the significant influence of antecedent wetness on rapid discharge events.
• Composite threshold scanning yielded effective candidate rules for flood early warnings, characterized by high precision, moderate hit rates, and low false-alarm rates.

Contributions

• Developed a novel framework integrating satellite and ground-based soil moisture with hydro-meteorological data to overcome spatial sparsity and temporal gaps in soil moisture observations, producing a continuous daily basin-representative soil moisture series.
• Quantified the critical role of antecedent wetness and precipitation in influencing rapid discharge events in South Korean dam basins.
• Derived practical and effective composite thresholds for flash-flood early warning systems, enhancing flood preparedness and response capabilities in the region.

Funding

Not available in the provided text.

Citation

@article{Lee2026Satellite,
  author = {Lee, Jaehoon and Yang, Jeong-Seok},
  title = {Satellite- and Ground-Soil-Moisture Synchronization and Rainfall Index Linkage for Developing Early-Warning Thresholds for Flash Floods in Korean Dam Basins},
  journal = {Water},
  year = {2026},
  doi = {10.3390/w18080909},
  url = {https://doi.org/10.3390/w18080909}
}