Sun et al. (2025) High-resolution streamflow simulation, trend and drought analysis in China (1980–2022): A large-scale routing model based on improved geomorphic functions

Identification

• Journal: Journal of Hydrology Regional Studies
• Year: 2025
• Date: 2025-10-30
• Authors: Zhaomin Sun, Zhiyong Wu, Jingjing Liu, Hai He, Luca Brocca, Zhenchen Liu
• DOI: 10.1016/j.ejrh.2025.102892

Research Groups

• College of Hydrology and Water Resources, Hohai University, Nanjing, China
• National Key Laboratory of Water Disaster Prevention, Hohai University, Nanjing, China
• North China Power Engineering CO., LTD. of China Power Engineering Consultant Group, Beijing, China
• Research Institute for Geo-Hydrological Protection, National Research Council, Perugia, Italy

Short Summary

This study developed improved geomorphic functions for China and integrated them with the Variable Infiltration Capacity (VIC) model to reconstruct high-resolution streamflow across China from 1980 to 2022. The research revealed an overall increasing streamflow trend in eastern regions, declining trends in western regions, and detailed spatiotemporal characteristics of hydrological droughts, including a contraction in drought extent after 2013.

Objective

• To improve routing parameterization by establishing and evaluating river geomorphic functions across China, thereby enhancing the spatial representation of routing in large-scale hydrological simulations.
• To provide high-resolution, spatially continuous streamflow data for nationwide hydrological change assessments by reconstructing grid-based streamflow processes and analyzing inter-annual and intra-annual variations of major Chinese rivers.
• To contribute to a systematic understanding of the spatiotemporal dynamics and regional differences of hydrological drought by examining their evolution and characteristics based on the reconstructed streamflow data.

Study Configuration

• Spatial Scale: Entirety of China, covering nine hydroclimatic basins, simulated on a 5 km × 5 km grid.
• Temporal Scale: Streamflow simulation and analysis from 1980 to 2022, with 1979 as a warm-up period.

Methodology and Data

• Models used:
  • Variable Infiltration Capacity (VIC) model for runoff generation.
  • Large-scale routing model (improved by Lu et al. (2015), based on Lohmann et al. (1996)) for streamflow routing, incorporating newly established geomorphic functions.
• Data sources:
  • Hydrological data: Daily streamflow data from the Ministry of Water Resources Information Center and hydrological information (annual maximum daily streamflow, watershed area, streamflow, velocity, river surface water width) from Hydrological Yearbooks for selected flow-gauge stations.
  • Meteorological data: Daily data from 843 meteorological stations (China Meteorological Data Sharing Network) for 1979–2022, used as input for the runoff model.
  • DEM data: Digital Elevation Model (International Scientific & Technical Data Mirror Site, Computer Network Information Center, Chinese Academy of Sciences) for river network division and routing direction.

Main Results

• Geomorphic Functions: Region-specific geomorphic functions for China demonstrated good fitting performance, with correlation coefficients for ln(watershed area) and ln(streamflow) ranging from 0.65 to 0.99, and for ln(streamflow) and ln(river width) ranging from 0.70 to 0.92.
• Streamflow Simulation Accuracy: The integrated model provided reliable streamflow simulations across China, with a mean absolute relative error (ER) of 10.2 % and a mean Nash-Sutcliffe Efficiency (NSE) of 0.69 across 20 validation stations. Southern regions showed higher process simulation accuracy (mean NSE = 0.73) while northern regions showed better water balance simulation (mean absolute ER = 6.68 %).
• Streamflow Trends (1980–2022): An overall increasing trend in streamflow was observed across China, particularly in eastern regions (e.g., Songhua-Liaohe River Basin, northern Huaihe River Basin, middle Yangtze River Basin). Conversely, western rivers exhibited a declining trend, which was more pronounced for low-flow conditions (below the 50th percentile). Seasonal contributions to these trends varied significantly across basins.
• Drought Characteristics: Widespread drought conditions were prevalent from 1993 to 2013, followed by a notable contraction in drought extent after 2013. Southern basins exhibited more spatially homogeneous patterns in drought severity and frequency compared to northern regions. Drought propagation along river channels and local intensification were observed during typical drought events.

Contributions

• Developed and evaluated a novel set of river geomorphic functions for the entirety of China, significantly improving the parameterization and spatial representation of large-scale hydrological routing models.
• Generated a high-resolution (5 km × 5 km), spatially continuous, and long-term (1980–2022) streamflow dataset for China, addressing limitations of sparse gauging stations.
• Provided a comprehensive analysis of streamflow trends (annual, seasonal, percentile-based, and decadal) and spatiotemporal characteristics of hydrological droughts across China, offering detailed insights into regional hydrological changes.
• Established an improved framework for national-scale hydrological simulation and drought monitoring, offering scientific support for water resources management and climate change adaptation in China.

Funding

• National Natural Science Foundation of China (U2240225, 52579007)
• Postgraduate Research & Practice Innovation Program of Jiangsu Province (KYCX23_0715)
• National Key Laboratory of Water Disaster Prevention (524015512)
• China Scholarship Council (202306710131)
• European Union “Open Earth Monitor Cyberinfrastructure” project (101059548)

Citation

@article{Sun2025Highresolution,
  author = {Sun, Zhaomin and Wu, Zhiyong and Liu, Jingjing and He, Hai and Brocca, Luca and Liu, Zhenchen},
  title = {High-resolution streamflow simulation, trend and drought analysis in China (1980–2022): A large-scale routing model based on improved geomorphic functions},
  journal = {Journal of Hydrology Regional Studies},
  year = {2025},
  doi = {10.1016/j.ejrh.2025.102892},
  url = {https://doi.org/10.1016/j.ejrh.2025.102892}
}

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