Luo et al. (2026) Global net increase in surface water connectivity in river–floodplain systems

Identification

• Journal: Nature Geoscience
• Year: 2026
• Date: 2026-04-02
• Authors: Qiuqi Luo, Lian Feng, Edward Park, Des E. Walling, Lei Huang, Mengqiu Wang, R. Iestyn Woolway, Hongwei Fang, Jianya Gong
• DOI: 10.1038/s41561-026-01953-y

Research Groups

• State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan, China
• School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, China
• National Institute of Education, Nanyang Technological University, Singapore, Singapore
• Earth Observatory of Singapore and Asian School of the Environment, Nanyang Technological University, Singapore, Singapore
• Center for Climate Change and Environmental Health, Nanyang Technological University, Singapore, Singapore
• Department of Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, UK
• The State Key Laboratory of Hydro Science and Engineering, Department of Hydraulic Engineering, Tsinghua University, Beijing, China
• Department of Earth and Planetary Sciences, The University of Hong Kong, Hong Kong SAR, China
• School of Ocean Sciences, Bangor University, Menai Bridge, UK

Short Summary

This study analyzed nearly four decades (1984–2019) of satellite observations to assess global changes in surface water connectivity across 1.6 million kilometers of river–floodplain systems, revealing a net global increase of 3% driven primarily by climatic factors and modulated by human activities.

Objective

• To analyze the global spatial and temporal patterns of surface water connectivity in river–floodplain systems over nearly four decades (1984–2019), identify its drivers, and understand its implications for global water cycles, biogeochemical fluxes, geomorphology, and ecosystem health.

Study Configuration

• Spatial Scale: Global, covering 1.6 million kilometers of river length, representing 73% of the total global river length, focusing on river–floodplain systems.
• Temporal Scale: Four decades (1984–2019).

Methodology and Data

• Models used: Satellite-based surface water connectivity index calculation using MATLAB code.
• Data sources:
  • Satellite observations: Global Surface Water Occurrence (GSWO) dataset, Global River Widths from Landsat (GRWL) dataset, Landsat missions.
  • Floodplain datasets: GFPLAIN250m, SHIFT.
  • Precipitation products: Climatic Research Unit gridded time series (CRU TS), Multi-Source Weighted-Ensemble Precipitation (MSWEP), ERA5L reanalysis dataset.
  • Actual evapotranspiration products: Global Land Evaporation Amsterdam Model (GLEAM), Modern-Era Retrospective Analysis for Research and Applications version 2 (MERRA-2) dataset, ERA5L reanalysis dataset.
  • Suspended sediment concentrations dataset.
  • HydroBASINS dataset.
  • Satellite-based surface water connectivity data at pixel and reach levels.

Main Results

• A net global increase of +3% in surface water connectivity was observed in river–floodplain systems between 1984 and 2019.
• Continuous gains in connectivity occurred across 17% of the global river length, approximately 1.5 times the length experiencing continuous losses.
• Connectivity gains were most pronounced in eastern Asia and high-latitude regions.
• Arid and semi-arid regions exhibited widespread declines in connectivity.
• Climatic drivers, including shifts in precipitation and evapotranspiration, predominantly shaped these changes, with human activities like dam construction providing additional modulation.
• A strong positive coupling was identified between surface water connectivity and riverine sediment transport in regions undergoing significant connectivity changes, highlighting its role in shaping sediment fluxes and associated biogeochemical processes.

Contributions

• Provides the first global, nearly four-decade record of surface water connectivity in river–floodplain systems and its evolution.
• Quantifies the net global increase in connectivity and identifies distinct regional patterns of gains and losses.
• Elucidates the dominant climatic drivers and modulating anthropogenic impacts on surface water connectivity changes.
• Establishes a significant link between surface water connectivity and riverine sediment transport, underscoring its broader ecological and biogeochemical importance.
• Offers crucial insights to inform sustainable management strategies for river–floodplain systems amidst escalating climatic and anthropogenic pressures.

Funding

• National Natural Science Foundation of China (grant number 42425604)
• National Key Research and Development Program of China (grant number 2022YFC3201802)
• Shenzhen Science and Technology Program (grant no. KCXFZ20240903093659003)
• Singapore Ministry of Education (MOE) AcRFs Tier2 (MOE-T2EP50222-0007)
• Tier 3 Climate Transformation Programme (MOE-MOET32022-0006)
• UKRI Natural Environment Research Council (NERC) Independent Research Fellowship [NE/T011246/1]

Citation

@article{Luo2026Global,
  author = {Luo, Qiuqi and Feng, Lian and Park, Edward and Walling, Des E. and Huang, Lei and Wang, Mengqiu and Woolway, R. Iestyn and Fang, Hongwei and Gong, Jianya},
  title = {Global net increase in surface water connectivity in river–floodplain systems},
  journal = {Nature Geoscience},
  year = {2026},
  doi = {10.1038/s41561-026-01953-y},
  url = {https://doi.org/10.1038/s41561-026-01953-y}
}