Li et al. (2026) Cascade-reservoir impoundment reshapes event-scale flood–sediment responses upstream of the Three Gorges Reservoir: evidence from rainfall patterns and driver attribution

Identification

• Journal: Journal of Hydrology
• Year: 2026
• Date: 2026-08-06
• Authors: Xin Li, Xinyu Peng, Wei Zhang, Ya Liu
• DOI: 10.1016/j.jhydrol.2026.136192

Research Groups

State Key Laboratory of Water Resources Engineering and Management, Wuhan University
Changjiang River Scientific Research Institute, Key Laboratory of Changjiang River of Ministry of Water Resources

Short Summary

This study investigates the impact of cascade-reservoir impoundment on event-scale flood-sediment responses in the Three Gorges Reservoir (TGR) inflow region. The research reveals a decoupling between flood and sediment dynamics, with rainfall magnitude governing floods and spatial organization of rainfall and reservoir-induced sediment-supply limitation controlling sediment delivery.

Objective

• Investigate how cascade-reservoir impoundment affects event-scale flood-sediment responses in the TGR inflow region

Study Configuration

• Spatial Scale: Event-scale flood and suspended sediment dynamics in the Three Gorges Reservoir (TGR) inflow region
• Temporal Scale: 91 flood-season events during 2003–2020

Methodology and Data

• Models used: Random forest framework, SHAP interpretation, and RF-MDI feature-importance validation
• Data sources: Rainfall patterns, flood and suspended-sediment responses, and driver attribution analysis using satellite and observation data

Main Results

• Flood responses entering the TGR weakened moderately after cascade-reservoir impoundment, with total flood volume, peak discharge, and flood duration decreasing by approximately 10.0%, 6.2%, and 8.5%, respectively
• Sediment responses declined more sharply, with suspended-sediment load and mean/peak suspended-sediment concentrations decreasing by 49.4%, 52.9%, and 41.3%
• Flood events accounted for a slightly larger share of annual sediment load, indicating stronger event-scale concentration of sediment delivery under reduced sediment supply

Contributions

• This study provides new insights into the decoupling between flood and sediment dynamics in heavily regulated large river basins
• The findings offer implications for sediment monitoring, flood-season reservoir operation, and adaptive water-sediment management in large, heavily regulated river basins

Funding

• This research was supported by [project name], [program name], and [reference code]

Citation

@article{Li2026Cascadereservoir,
  author = {Li, Xin and Peng, Xinyu and Zhang, Wei and Liu, Ya},
  title = {Cascade-reservoir impoundment reshapes event-scale flood–sediment responses upstream of the Three Gorges Reservoir: evidence from rainfall patterns and driver attribution},
  journal = {Journal of Hydrology},
  year = {2026},
  doi = {10.1016/j.jhydrol.2026.136192},
  url = {https://doi.org/10.1016/j.jhydrol.2026.136192}
}