scholarly journals Dynamics of Mid-Channel Bar during Different Impoundment Periods of the Three Gorges Reservoir Area in China

Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3427
Author(s):  
Qingqing Tang ◽  
Daming Tan ◽  
Yongyue Ji ◽  
Lingyun Yan ◽  
Sidong Zeng ◽  
...  
Keyword(s):  
Water Level ◽  
Three Gorges Reservoir ◽  
Hydrological Regime ◽  
Temporal Variations ◽  
Three Gorges Reservoir Area ◽  
Three Gorges ◽  
The Three Gorges Reservoir ◽  
The Three Gorges ◽  
Water Level Changes ◽  
Influence Of Water

The dynamics of the mid-channel bars (MCBs) in the Three Gorges Reservoir (TGR) were substantially impacted by the large water-level changes due to the impoundments of the TGR. However, it is still not clear how the morphology of the MCBs changed under the influence of water level and hydrological regime changes induced by the impoundments and operation of the TGR. In this work, the MCBs in the TGR were retrieved using Landsat remote sensing images from 1989 to 2019, and the spatio-temporal variations in the number, area, morphology and location of the MCBs during different impoundment periods were investigated. The results showed that the number and area of MCBs changed dramatically with water-level changes, and the changes were dominated by MCBs with an area less than 0.03 km2 and larger than 1 km2. The area of MCBs decreased progressively with the rising water level, and the number generally showed a decreasing trend, with the minimum number occurring at the third stage when the water level reached 139 m, resulting in the maximum average area at this period. The ratio of length to width of the MCBs generally decreased with the changes in hydrological and sediment regimes, leading to a shape adjustment from narrow–long to relatively short–round with the rising of the water level. The water impoundments of the TGR led to the migration of the dominant area from the upper section to the middle section of the TGR and resulted in a more even distribution of MCBs in the TGR. The results improve our understanding of the mechanisms of the development of MCBs in the TGR under the influence of water impoundment coupled with the annually cyclic hydrological regime and longer periods of inundation and exposure.

Influence of Water Level on Cynodon dactylon Population in Water-Level-Fluctuating Zone of the Three Gorges Reservoir

2013 ◽  
Vol 295-298 ◽  
pp. 1857-1861
Author(s):  
Qiang Li
Keyword(s):  
Water Level ◽  
Three Gorges Reservoir ◽  
Cynodon Dactylon ◽  
Stem Length ◽  
Three Gorges ◽  
Node Number ◽  
The Three Gorges Reservoir ◽  
The Three Gorges ◽  
Water Level Changes ◽  
Influence Of Water

To research influence of water level changes on vegetations restoration in water-level-fluctuating zone of the Three Gorges Reservoir, Cynodon dactylon in Changshou area was respectively investigated in 2008 and 2009. The results show that germination rate in 2009 is 45.3% lower than that in 2008. Total rhizome length and total node number of rhizomes in 2009 significantly increase by 303.5% and 411.1%, respectively. However, stem length, node number, leaf width and leaf number of ramets decrease by 60.1%, 55.1%, 28.6% and 33.8%, respectively. Meanwhile, total buds number, germinated buds number and buds number to rhizome length ratio in 2009 increase by 500.7%, 228.5% and 50.9%, respectively. Compared with 2008, fresh mass of ramats, rhizomes and roots reduce respectively 65.6%, 23.4% and 70.0%, and their dry mass reduce respectively 65.9%, 18.8% and 64.5%. Therefore, water level changes accelerate rhizomes extension and the formation of buds and ramets, and inhibite ramets growth.

Reservoir-Induced Seismicity in the Three Gorges Reservoir Area

2014 ◽  
Vol 501-504 ◽  
pp. 1477-1485
Author(s):  
Su Mei Liu ◽  
Xiang Dong Xie
Keyword(s):  
Water Level ◽  
Induced Seismicity ◽  
Three Gorges Reservoir ◽  
Three Gorges Reservoir Area ◽  
Three Gorges ◽  
Low Level ◽  
The Three Gorges Reservoir ◽  
Reservoir Induced Seismicity ◽  
The Three Gorges ◽  
Pressure Diffusion

As a region with little or very low level background seismicity, the impoundment of the Three Gorges Reservoir in June 2003 was related to increasing reservoir-induced seismicity. Analysis of the spatial pattern of seismicity showed that a majority of the seismicity was associated with the heavily fractured, deep crustal Jiuwanxi Fault, especially in regions of permeable Carbonate rocks formations. Analysis of the temporal pattern of the seismicity and a comparison with the filling history of the reservoir showed that the frequency and intensity of induced seismicity started at low level accompanying the impoundment of the Three Gorges Reservoir, and then increased with the increasing of water level and decreased thereafter. The amplitude of fluctuation of water level was found to be related to the frequency and intensity of induced seismicity. The pore pressure diffusion plays an important role in reservoir induced seismicity.

scholarly journals Landslide Characterization Applying Sentinel-1 Images and InSAR Technique: The Muyubao Landslide in the Three Gorges Reservoir Area, China

2020 ◽  
Vol 12 (20) ◽  
pp. 3385
Author(s):  
Chao Zhou ◽  
Ying Cao ◽  
Kunlong Yin ◽  
Yang Wang ◽  
Xuguo Shi ◽  
...  
Keyword(s):  
Water Level ◽  
Three Gorges Reservoir ◽  
In Situ Monitoring ◽  
Three Gorges Reservoir Area ◽  
Economic Losses ◽  
Landslide Monitoring ◽  
Three Gorges ◽  
Reservoir Area ◽  
The Three Gorges Reservoir ◽  
The Three Gorges

Landslides are a common natural hazard that causes casualties and unprecedented economic losses every year, especially in vulnerable developing countries. Considering the high cost of in-situ monitoring equipment and the sparse coverage of monitoring points, the Sentinel-1 images and Interferometric Synthetic Aperture Radar (InSAR) technique were used to conduct landslide monitoring and analysis. The Muyubao landslide in the Three Gorges Reservoir area in China was taken as a case study. A total of 37 images from March 2016 to September 2017 were collected, and the displacement time series were extracted using the Stanford Method for Persistent Scatterer (StaMPS) small baselines subset method. The comparison to global positioning system monitoring results indicated that the InSAR processing of the Muyubao landslide was accurate and reliable. Combined with the field investigation, the deformation evolution and its response to triggering factors were analyzed. During this monitoring period, the creeping process of the Muyubao landslide showed obvious spatiotemporal deformation differences. The changes in the reservoir water level were the trigger of the Muyubao landslide, and its deformation mainly occurred during the fluctuation period and high-water level period of the reservoir.

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