Wang et al. (2026) Water-balance health in China (2011–2018): UWBI assessment and elasticity-based driver attribution

Identification

• Journal: Earth Systems and Environment
• Year: 2026
• Date: 2026-03-27
• Authors: Bingyi Wang, Yulei Xie, Zhentong Wu, Lirong Liu
• DOI: 10.1007/s41748-026-01127-1

Research Groups

• School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou, P.R. China
• Centre for Environment and Sustainability, University of Surrey, Guildford, UK

Short Summary

This study developed an integrated natural-social water balance assessment framework to analyze the spatiotemporal patterns and drivers of water balance health in China from 2011 to 2018, revealing significant regional heterogeneity and identifying terrestrial water storage and total water use as key influencing factors.

Objective

• To develop an integrated natural-social water balance assessment framework that combines flux accounting, system coupling coordination, and elasticity-based attribution.
• To quantify and map the temporal-spatial distribution and evolution of water balance health across China from 2011 to 2018 using the Unhealthy Water Balance Index (UWBI).
• To identify the dominant natural and anthropogenic driving factors influencing regional water balance health and their seasonal variations.

Study Configuration

• Spatial Scale: Mainland China (excluding Hainan, Taiwan, Hong Kong, and Macau), analyzed on 0.25° grid cells and further aggregated by agricultural zones, climatic regions, and river basins.
• Temporal Scale: 2011–2018, with analysis of annual, monthly, and seasonal patterns.

Methodology and Data

• Models used:
  • Integrated natural-social water balance assessment framework.
  • Unhealthy Water Balance Index (UWBI) calculated as the geometric mean of the Natural Water Cycle Balance Index (NWCBI), Social Water Withdrawal Balance Index (SWUBI), and System Coupling Coordination Degree (UCI).
  • Elasticity coefficient method to quantify contributions of driving factors to UWBI.
  • Trend Consistency Index (TCI) for analyzing temporal trends in UWBI.
• Data sources:
  • Hydrological components: Precipitation and evapotranspiration (NASA GLDAS v2.2, monthly, 0.25°), Natural runoff (China Natural Runoff Dataset (CNRD v1.0), 0.25° × 0.25°), Root-zone soil moisture (ERA5-Land, MERRA-2, CFSR, 0–100 cm weighted average), Terrestrial water storage (precipitation-based reconstruction dataset).
  • Socioeconomic factors: Gridded annual GDP (Zhao et al. 2017), Population data (LandScan Global model), Water resources data (China Water Resources Bulletin, provincial statistics, downscaled to 0.25° monthly grids), Agricultural irrigation (satellite-based Global Irrigation Water Use dataset, 2011–2018), Industrial water use (provincial-level data, literature), Domestic water use (China Water Resources Bulletin, downscaled by population density and temperature-based function).
  • Ecological indicators: Fractional vegetation cover (China Regional Monthly FVC Product, 2000–2022, 250 m resolution).
  • Water transfer: China Inter-Basin Water Transfer Project Database (annual volumes, disaggregated to monthly and grid cells).

Main Results

• The national mean Unhealthy Water Balance Index (UWBI) for China from 2011 to 2018 was 0.33, with over 80% of regions classified as "balanced" or healthier.
• Water balance health exhibited pronounced spatial heterogeneity, characterized by a pattern of "lower in the west, higher in the east; stronger imbalance in the north, weaker in the south." Hotspots of severe imbalance were identified in the Huang-Huai-Hai Plain and Beijing-Tianjin-Hebei urban agglomeration.
• Temporally, the unhealthy water balance status showed an intensification followed by alleviation. In the North China Plain, UWBI declined from 0.82 in 2014 to 0.71 in 2018, coinciding with the full operation of the South-to-North Water Diversion Middle Route Project.
• A distinct seasonal cycle was observed, with UWBI peaking in April (0.39) and October (0.38), and reaching its lowest levels in July and December (both 0.29). Water balance health was generally "high in spring and autumn, moderate in summer, and optimal in winter."
• Trend consistency analysis revealed that 61.83% of the country experienced a deterioration (growth trend) in water balance health, particularly in northwestern arid zones and the Qinghai–Tibet Plateau. Conversely, humid regions of South and Central China showed improving trends.
• Terrestrial Water Storage (TWS) was the principal factor affecting regional unhealthy water balance across 42.98% of the country, with 88.99% of TWS-dominated regions showing a negative contribution (mean elasticity -0.32).
• Total Water Use (TWU) was the second most influential factor (27.13% of area), consistently contributing positively to unhealthy water balance (mean elasticity 0.29 across 93.25% of TWU-dominated regions).
• Fractional Vegetation Cover (FVC) was dominant in 22.23% of the area, showing variable effects (mean elasticity -0.10, 59.60% negative).
• Seasonal shifts in dominant factors were observed, with FVC remaining predominant in all seasons but declining in winter, while the influence of Runoff (RO) and TWU increased.

Contributions

• Developed a novel, integrated natural-social water balance assessment framework that combines flux accounting, system coupling coordination, and elasticity-based attribution, providing a comprehensive perspective on water balance health.
• Introduced the Unhealthy Water Balance Index (UWBI) as a unified, quantitative, and interpretable metric for assessing and mapping regional water balance health, integrating natural hydrological processes, social water withdrawals, and system coordination.
• Provided a detailed spatiotemporal analysis of water balance health in China from 2011 to 2018, revealing pronounced regional heterogeneity, spatial contrasts, and strong seasonal variability.
• Quantified the contributions of dominant natural and anthropogenic drivers (e.g., TWS, TWU, FVC, ET) to water balance health variations and identified their seasonal shifts, offering insights into system control mechanisms.
• Offered a quantitative and interpretable basis for diagnosing water balance health and supporting the development of region-specific strategies for sustainable water resource management and allocation.

Funding

• National Natural Science Foundation of China (No. 52479007, and 52222901)
• Sichuan Science and Technology Program (No. 2023YFQ0105)
• National Key Research and Development Program of China (No. 2022YFC3202205)

Citation

@article{Wang2026Waterbalance,
  author = {Wang, Bingyi and Xie, Yulei and Wu, Zhentong and Liu, Lirong},
  title = {Water-balance health in China (2011–2018): UWBI assessment and elasticity-based driver attribution},
  journal = {Earth Systems and Environment},
  year = {2026},
  doi = {10.1007/s41748-026-01127-1},
  url = {https://doi.org/10.1007/s41748-026-01127-1}
}