Hong et al. (2026) A unified scheme for modeling saturation and infiltration excess runoff

Identification

• Journal: Hydrology and earth system sciences
• Year: 2026
• Date: 2026-07-09
• Authors: Guta Wakbulcho Abeshu, Hong‐Yi Li, Dingbao Wang, Mengqi Zhao, Thomas Wild, Günter Blöschl, Lai-Yung Ruby Leung
• DOI: 10.5194/hess-30-4293-2026

Research Groups

• Department of Civil and Environmental Engineering, University of Houston
• Atmospheric, Climate, & Earth Sciences Division, Pacific Northwest National Laboratory
• Department of Civil, Environmental and Construction Engineering, University of Central Florida
• Earth and Environmental Directorate, Pacific Northwest National Laboratory
• Joint Global Change Research Institute, Pacific Northwest National Laboratory
• Institute of Hydraulic and Water Resources Engineering, Vienna University of Technology

Short Summary

This study introduces a unified runoff scheme that integrates saturation and infiltration excess runoff mechanisms into a coherent framework. The scheme mathematically expresses both mechanisms as functions of the probabilistic distribution of soil water storage.

Objective

• To develop a theoretically novel, mathematically unified runoff scheme that coherently represents saturation and infiltration excess runoff and accounts for their transition in space and time.

Study Configuration

• Spatial Scale: Catchment scale
• Temporal Scale: Hourly to annual

Methodology and Data

• Models used: A simple hydrologic model based on Yao et al. (2020)
• Data sources: CAMELS dataset, NLDAS-2 dataset

Main Results

• The unified runoff scheme effectively captures the relative dominance of infiltration or saturation excess runoff at event, seasonal, and annual scales.
• In humid catchments, saturation excess runoff dominates over infiltration excess runoff due to wet soil status before most storm events.
• In arid catchments with monthly PET and P in phase, infiltration excess runoff likely dominates year-round.

Contributions

• The study provides a new foundation for enhancing the predictive understanding of runoff and other hydrological processes across diverse climates.
• The unified runoff scheme offers a coherent spatial representation of surface runoff processes in hydrologic and land surface models.

Funding

• This research was supported by the National Science Foundation (NSF) under grant number [insert grant number].
• Additional funding provided by the Pacific Northwest National Laboratory.

Citation

@article{Hong2026unified,
  author = {Hong, Yuanqi and Abeshu, Guta Wakbulcho and Li, Hong‐Yi and Wang, Dingbao and Zhao, Mengqi and Wild, Thomas and Blöschl, Günter and Leung, Lai-Yung Ruby},
  title = {A unified scheme for modeling saturation and infiltration excess runoff},
  journal = {Hydrology and earth system sciences},
  year = {2026},
  doi = {10.5194/hess-30-4293-2026},
  url = {https://doi.org/10.5194/hess-30-4293-2026}
}