Wen et al. (2026) Ecological water replenishment improves water quality and environmental capacity in a tributary of the Yellow River: insights from MIKE 21 coupled modeling

Identification

• Journal: Journal of Hydrology
• Year: 2026
• Date: 2026-08-14
• Authors: Yihao Wen, Junzheng Liu, Haijue Xu, Jinliang Zhang, Yuchuan Bai, Yao Wang
• DOI: 10.1016/j.jhydrol.2026.136224

Research Groups

• State Key Laboratory of Hydraulic Engineering Intelligent Construction and Operation, Tianjin University, China
• Institute for Sedimentation on River and Coastal Engineering, Tianjin University, China
• Yellow River Engineering Consulting Co. Ltd, Zhengzhou, China
• Key Laboratory of Water Management and Water Security for Yellow River Basin of Ministry of Water Resources (Under Construction), Zhengzhou, China

Short Summary

This study developed a coupled hydrodynamic-water quality model based on MIKE 21 to quantify the effects of ecological water replenishment scenarios on water quality and environmental capacity in the Yi River, a key tributary of the Yellow River Basin.

Objective

• Investigate the impact of ecological water replenishment strategies on modeled water quality and environmental capacity in a seasonally water-scarce river.

Study Configuration

• Spatial Scale: Reach-scale (Yi River)
• Temporal Scale: Monthly time step for 1 year, with three non-replenishment scenarios and three replenishment strategies applied under critical dry-year hydrodynamic conditions

Methodology and Data

• Models used: MIKE 21 coupled hydrodynamic-water quality model
• Data sources: Hydrological data from gauging stations, water quality monitoring data from in-situ measurements

Main Results

• High-discharge, short-duration replenishment (2Q, T/2) produced the greatest modeled water-quality improvement among tested equal-volume constant-discharge scenarios, reducing comprehensive pollution index by 50.4% and increasing downstream DO by 227.33%.
• Modeled total water environmental capacity after EWR was 33.6% higher than that before EWR.

Contributions

• Provided a quantitative framework for comparing water-quality-oriented EWR scenarios and identifying pollution-control priorities during low-flow periods.
• Highlighted the importance of evaluating hydrological regulation together with pollution control and capacity-based water-quality management in seasonally water-scarce rivers.

Funding

• This research was supported by the National Natural Science Foundation of China (Grant No. 52109214) and the Yellow River Engineering Consulting Co. Ltd.

Citation

@article{Wen2026Ecological,
  author = {Wen, Yihao and Liu, Junzheng and Xu, Haijue and Zhang, Jinliang and Bai, Yuchuan and Wang, Yao},
  title = {Ecological water replenishment improves water quality and environmental capacity in a tributary of the Yellow River: insights from MIKE 21 coupled modeling},
  journal = {Journal of Hydrology},
  year = {2026},
  doi = {10.1016/j.jhydrol.2026.136224},
  url = {https://doi.org/10.1016/j.jhydrol.2026.136224}
}