Chen et al. (2025) Spatiotemporal variation of forest water conservation based on dual-variable calibration of runoff and evapotranspiration with SWAT model

Identification

• Journal: Agricultural and Forest Meteorology
• Year: 2025
• Date: 2025-07-26
• Authors: Lin Feng, Xingwei Chen, Huaxia Yao
• DOI: 10.1016/j.agrformet.2025.110755

Research Groups

• School of Geographical Sciences, Fujian Normal University, China
• Key Laboratory of Humid Subtropical Eco-geographical Processes of Ministry of Education, Fujian Normal University, China
• Department of Geography, Nipissing University, Canada

Short Summary

The study introduces a dual-variable calibration approach for the SWAT model, combining observed runoff and corrected evapotranspiration (ET) products to more accurately quantify forest water conservation in the Shanmei Reservoir Watershed.

Objective

• To overcome the limitations of traditional SWAT model calibration (which relies solely on runoff) to more accurately depict the water cycle and quantify the spatiotemporal variations of forest water conservation.

Study Configuration

• Spatial Scale: Shanmei Reservoir Watershed (SMRW), southeastern coast of China.
• Temporal Scale: 2005–2016.

Methodology and Data

• Models used: Soil and Water Assessment Tool (SWAT).
• Data sources: Observed runoff, various ET products (including FLDAS), and water balance data.
• Approach: Regional adaptation assessment and correction of ET products based on water balance principles, followed by dual-variable calibration of the SWAT model using both observed runoff and the corrected ET data.

Main Results

• ET Correction: The correction method was validated as effective, with relative errors of corrected ET products being $< 1\%$ when the time series used for water balance analysis was $\ge 11$ years.
• Model Performance: Dual-variable calibration improved the simulation of daily runoff and spatiotemporal ET variations; among the products tested, corrected FLDAS ET yielded the best performance.
• Water Conservation Quantities: For the period 2005–2016, the multi-year average forest water conservation was $574.05\text{ mm}$ and the forest water conservation coefficient was $0.31$.
• Spatial Distribution: Forest water conservation followed a pattern of being high in the east and west and low in the middle of the watershed.
• Driving Factors: Precipitation and forested land area were identified as the primary factors influencing forest water conservation.

Contributions

• Proposed an improved SWAT calibration framework that integrates corrected ET products, providing a more reasonable and accurate method for reflecting the spatiotemporal variations of forest water conservation than traditional runoff-only calibration.

Funding

• Not specified in the provided text.

Citation

@article{Chen2025Spatiotemporal,
  author = {Chen, Jiao and Zheng, Meiling and Feng, Lin and Chen, Xingwei and Yao, Huaxia},
  title = {Spatiotemporal variation of forest water conservation based on dual-variable calibration of runoff and evapotranspiration with SWAT model},
  journal = {Agricultural and Forest Meteorology},
  year = {2025},
  doi = {10.1016/j.agrformet.2025.110755},
  url = {https://doi.org/10.1016/j.agrformet.2025.110755}
}