Large-scale sediment and phosphorus transport in the Three Gorges Reservoir based on a new reservoir operation method

Xiaoya Tang; Sidong Zeng; Guoxian Huang; Sichen Tong; Fei Qiao; Yuanxin Ren; Xingxing Zhang

doi:10.1016/j.envres.2023.116386

Large-scale sediment and phosphorus transport in the Three Gorges Reservoir based on a new reservoir operation method

Environ Res. 2023 Sep 15:233:116386. doi: 10.1016/j.envres.2023.116386. Epub 2023 Jun 10.

Authors

Xiaoya Tang¹, Sidong Zeng², Guoxian Huang³, Sichen Tong⁴, Fei Qiao⁵, Yuanxin Ren², Xingxing Zhang⁴

Affiliations

¹ Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China; Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
² Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China.
³ Chinese Research Academy of Environmental Sciences, Beijing, 100012, China. Electronic address: huanggx@craes.org.cn.
⁴ Key Laboratory of Hydraulic and Waterway Engineering of the Ministry of Education, Chongqing Jiaotong University, Chongqing, 400074, China.
⁵ Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.

PMID: 37308070
DOI: 10.1016/j.envres.2023.116386

Abstract

Change of hydrodynamic conditions is a key factor inducing sedimentation, water eutrophication and algal blooms in the Three Gorges Reservoir (TGR). How to mitigate sedimentation and phosphorus (P) retention by improving hydrodynamic conditions in the Three Gorges Reservoir area (TGRA) is an urgent issue in the study of sediment and water environment. In this study, a Hydrodynamic-Sediment-Water quality model for the whole TGRA is proposed considering sediment and P inputs from numerous tributaries, and a new reservoir operation method namely the tide-type operation method (TTOM) is used to investigate the large-scale sediment and P transport in the TGR based on the model. Results indicate that the TTOM can reduce sedimentation and total phosphorus (TP) retention in the TGR. Compared with the actual operation method (AOM), sediment outflow and sediment export ratio (E_ratio) of the TGR increased about 17.13% and 1%-3% in 2015-2017, and sedimentation decreased about 3% under the TTOM. TP retention flux and retention rate (RE) decreased about 13.77% and 2%-4%. The flow velocity (V) and sediment carrying capacity (S*) increased about 40% in the local reach. Larger daily water level fluctuation at dam site is more conducive to reducing sedimentation and TP retention in the TGR. Sediment inputs from the Yangtze River, Jialing River, Wu River and other tributaries account for 59.27%, 11.21%, 3.81% and 25.70% of the total sediment inflow during 2015-2017, and TP inputs were 65.96%, 10.01%, 17.40% and 6.63%. In the paper, an innovative method is proposed to reduce sedimentation and P retention in the TGR under the given hydrodynamic conditions and related quantitative contribution driven by the proposed method is analyzed. The work is favorable for expanding the understanding of the hydrodynamic and nutrition flux changes in the TGR, and provides a new perspective for water environment protection and reasonable operation of large reservoirs.

Keywords: Hydrodynamic-sediment-water quality model; Sedimentation; TP retention; Three Gorges Reservoir; Tide-type operation method.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

China
Environmental Monitoring / methods
Eutrophication
Phosphorus* / analysis
Rivers
Water Pollutants, Chemical* / analysis
Water Quality

Substances

Phosphorus
Water Pollutants, Chemical