scholarly journals Effects of water level fluctuation on thermal stratification in a typical tributary bay of Three Gorges Reservoir, China

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6925 ◽  
Author(s):  
Juxiang Jin ◽  
Scott A. Wells ◽  
Defu Liu ◽  
Guolu Yang ◽  
Senlin Zhu ◽  
...  
Keyword(s):  
Water Level ◽  
Thermal Stratification ◽  
Three Gorges Reservoir ◽  
Thermocline Depth ◽  
Three Gorges ◽  
Algae Blooms ◽  
Xiangxi River ◽  
Bottom Depth ◽  
Field Data Analysis ◽  
The Impact

Xiangxi River is a typical tributary of Three Gorges Reservoir (TGR) in China. Based on field observations in 2010, thermal stratification was significant in most months of the year. Through field data analysis and numerical simulations, the seasonal and spatial variation of thermal stratification as related to the impact of the operation of TGR were investigated. Thermal stratification was most pronounced from April to September in the Xiangxi River tributary. Air temperature (AT) and water level (WL) were the two dominant variables impacting thermal stratification. AT affected the surface water temperature promoting the formation of thermal stratification, and high WLs in TGR deepened the thermocline depth and thermocline bottom depth. These results provide a preliminary description of the seasonal variation and spatial distribution of thermal stratification, which is important for better understanding how thermal stratification affects algae blooms in Xiangxi River.

Geomechanics Study on the Influence of Water Level Variation on Landslide Safety in Three Gorges Reservoir Region

2014 ◽  
Vol 540 ◽  
pp. 181-184
Author(s):  
Dong Fang Tian
Keyword(s):  
Water Level ◽  
Three Gorges Reservoir ◽  
High Water ◽  
Three Gorges ◽  
Level Variation ◽  
Water Level Variation ◽  
Three Gorges Reservoir Region ◽  
Influence Of Water ◽  
The Impact ◽  
Dangerous Condition

Up concave and linear slices are two basic geometric shapes of the landslides. In this paper, the unsaturated seepage fields of landslides are described by Richards’s equation and the safety of landslides are calculated by the Morgenstern-Prince method. The Influences of water level variation on landslide safety in Three Gorges reservoir region are discussed through two landslides. It indicates that,the impact of buoyancy is significant and related closely to water level change, and the most dangerous condition is stable high water level. To the slide which slice is line, the impact of permeation is significant and related closely to water change too, and the most dangerous condition is at the beginning of reaching the low water level.

scholarly journals Simulation of the Dynamic Water Storage and Its Gravitational Effect in the Head Region of Three Gorges Reservoir Using Imageries of Gaofen-1

2020 ◽  
Vol 12 (20) ◽  
pp. 3353
Author(s):  
Xian Ma ◽  
Linsong Wang ◽  
Chao Chen ◽  
Jinsong Du ◽  
Shida Sun
Keyword(s):  
High Resolution ◽  
Water Level ◽  
Three Gorges Reservoir ◽  
Water Storage ◽  
Three Gorges ◽  
Head Region ◽  
Gravitational Effects ◽  
Storage Model ◽  
Mass Load ◽  
The Impact

The construction of a high-resolution dynamic water storage model, driven by the mass load of the huge water storage of the Three Gorges Reservoir (TGR), is the necessary basic data for accurately simulating changes in the geophysical field, e.g., gravity, crustal deformation, and stress. However, previously established models cannot meet the needs of accurately simulating the impoundment effects of TGR, because these models were simplified and approximated and did not consider the variation of river boundaries caused by water level changes. In this study, we combined high-resolution Gaofen-1 (GF-1) satellite imageries and real-time water level in front of the dam and extracted 31 river boundaries of the head region of TGR between the lowest (145 m) and the highest (175 m) impoundment stages based on the Normalized Differential Water Index (NDWI) and threshold segmentation from Otsu method. Developed dynamic water storage model based on higher-resolution GF-1 data can show the true river boundary changes more exactly, especially in local areas. Compared to the previous approximate models, the model that we constructed accurately depicts the boundary distribution information of the different impoundment stages. Moreover, we simulated TGR-induced gravitational effects based on the high-precision forward modeling of the dynamic water storage model (i.e., considering changes of dynamic water area and water level). The theoretical modelled results are consistent with in situ gravity measurements with the difference mainly within 10 μGal. Our results indicate that water storage variations of TGR mainly affect the gravity field response within 1000 m of the reservoir bank with its maximum amplitude up to several hundred μGal. The dynamic water storage and its simulation results of gravitational effects can effectively eliminate the impact of surface water load driven by the TGR under human control and greatly improve the signal-to-noise ratio of regional gravity observational data. Thus, this work will be beneficial in the application of geophysical and geodetic monitoring aimed to comprehensively track the local and regional geological structural stability, e.g., artificial reservoir induced earthquake and landslide.

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