Wu et al. (2026) How interannual hydrological variability governs thermal stratification and selective withdrawal efficacy: Insights from the lower Lancang River cascade reservoirs

Identification

• Journal: Journal of Hydrology Regional Studies
• Year: 2026
• Date: 2026-09-09
• Authors: Hongshi Wu, Huqing Xu, Hongxue Zhang, Jianxia Chang, Lianpeng Zhang, Yimin Wang, Jinxi Li, Yige Wang, Junting Zhou
• DOI: 10.1016/j.ejrh.2026.103962

Research Groups

• School of Hydraulic and Civil Engineering, Ludong University
• Shandong Key Laboratory of Estuary and Coast & Nuclear Environment
• School of Water Conservancy & Civil Engineering, Northeast Agricultural University
• State Key Laboratory of Water Engineering Ecology and Environment in Arid Area, Xi’an University of Technology
• Zhoukou Branch of Hydrology and Water Resources Measurement and Reporting Center

Short Summary

This study investigated how interannual hydrological variability controls thermal stratification and selective withdrawal efficacy in the lower Lancang River cascade reservoirs. The results showed that utilizing multi-layer stoplog gates shifted withdrawal flows to warmer surface layers, raising downstream temperatures by a maximum of 8.34 ◦C.

Objective

• Investigate the relationship between interannual hydrological variability and thermal stratification in the lower Lancang River cascade reservoirs.
• Evaluate the efficacy of selective withdrawal via stoplog gates on downstream thermal habitats and hydropower generation.

Study Configuration

• Spatial Scale: The study area extends downstream from Nuozhadu to Ganlanba, covering a distance of approximately 100 km along the Lancang River.
• Temporal Scale: The study period spans three typical hydrological years (wet, normal, and dry) from March to September.

Methodology and Data

• Models used:
  • MIKE 3 model for simulating vertical water temperature distribution
  • Channel streamwise temperature distribution model for simulating downstream thermal responses
• Data sources:
  • Meteorological data (precipitation, evaporation, relative humidity, sunshine hours, temperature, and wind speed) from the National Climatic Centre of China
  • Hydrological data (monthly natural flow of the Nuozhadu, Jinghong, and Ganlanba hydropower stations) from 1953 to 2010
  • Water temperature data for Nuozhadu Reservoir from August 2014 to December 2015

Main Results

• The MIKE 3 model successfully captured the persistence and seasonal evolution of thermal stratification in the Nuozhadu Reservoir.
• Utilizing multi-layer stoplog gates shifted withdrawal flows to warmer surface layers, raising downstream temperatures by a maximum of 8.34 ◦C.
• The water temperature guarantee rate for fish spawning increased from 14.29% to 66.67%.

Contributions

• This study provides insights into the relationship between interannual hydrological variability and thermal stratification in cascade reservoirs.
• The results highlight the importance of selective withdrawal via stoplog gates on downstream thermal habitats and hydropower generation.

Funding

• This research was funded by the National Natural Science Foundation of China (Grant No. 51879009)
• The Shandong Key Laboratory of Estuary and Coast & Nuclear Environment (Grant No. QD20190401)

Citation

@article{Wu2026How,
  author = {Wu, Hongshi and Xu, Huqing and Zhang, Hongxue and Chang, Jianxia and Zhang, Lianpeng and Wang, Yimin and Li, Jinxi and Wang, Yige and Zhou, Junting},
  title = {How interannual hydrological variability governs thermal stratification and selective withdrawal efficacy: Insights from the lower Lancang River cascade reservoirs},
  journal = {Journal of Hydrology Regional Studies},
  year = {2026},
  doi = {10.1016/j.ejrh.2026.103962},
  url = {https://doi.org/10.1016/j.ejrh.2026.103962}
}