Optical Properties of Water Body in Xiaojiang River Backwater Area, Three Gorges Reservoir, 2008

2010 ◽  
Vol 113-116 ◽  
pp. 840-846
Author(s):  
Fang Fang ◽  
Hong Zhou ◽  
Jing Song Guo ◽  
Zhe Li ◽  
Yong Bo Chen ◽  
...  
Keyword(s):  
Optical Properties ◽  
Water Body ◽  
Three Gorges Reservoir ◽  
Light Attenuation ◽  
Particulate Matters ◽  
Three Gorges ◽  
Strong Correlations ◽  
Secchi Disc ◽  
The Impact ◽  
The Relationship

To discuss optical properties of water body in Xiaojiang river backwater area after the early impounding stage of the Three Gorges Reservoir (TGR), the correlations between visible light attenuation coefficients (Kd(PAR)) and Secchi Disc transparency (SD), total particulate matters (TPM), dissolved organic carbon (DOC) and chlorophyll-a (Chla) were investigated, and spatiotemporal variations of Kd(PAR) and its influencing factors were analyzed. In the study area, there are no significant spatial variations of Kd(PAR), but the seasonal changes are obvious, with the highest value in winter and the lowest value in summer. Statistics analysis suggests that there are strong correlations between Kd(PAR) and SD, TPM, TIM, the value of R2 are 0.7791, 0.7285, and 0.7637, respectively. The relationship between Kd(PAR) and DOC is less significant(R2=0.1289). However, the correlation between Kd(PAR) and Chla was weak (R2=0.006). Further study shows that, the impact of total particulate matters on the optical properties of water body is as a result of both seasonal impoundment of the TGR and particular hydrological condition of Xiaojiang river basin.

scholarly journals Impact of Three Gorges Reservoir Water Impoundment on Vegetation–Climate Response Relationship

2020 ◽  
Vol 12 (17) ◽  
pp. 2860
Author(s):  
Mengqi Tian ◽  
Jianzhong Zhou ◽  
Benjun Jia ◽  
Sijing Lou ◽  
Huiling Wu
Keyword(s):  
Human Activities ◽  
Three Gorges Reservoir ◽  
Climatic Factors ◽  
Residual Analysis ◽  
Sensitivity Index ◽  
Climate Response ◽  
Three Gorges ◽  
Response Relationship ◽  
The Impact ◽  
Water Impoundment

In recent years, the impact of global climate change and human activities on vegetation has become increasingly prominent. Understanding vegetation change and its response to climate variables and human activities are key tasks in predicting future environmental changes, climate changes and ecosystem evolution. This paper aims to explore the impact of Three Gorges Reservoir (TGR) water impoundment on the vegetation–climate response relationship in the Three Gorges Reservoir Region (TGRR) and its surrounding region. Firstly, based on the SPOT/VEGETATION NDVI and ERA5 reanalysis datasets, the correlation between climatic factors (temperature and precipitation) and NDVI was analyzed by using partial correlation coefficient method. Secondly, nonlinear fitting method was used to fit the mapping relationship between NDVI and climatic factors. Then, the residual analysis was conducted to evaluate the impact of TGR impoundment on vegetation–climate response relationship. Finally, sensitivity index (SI), sensitivity variation index (SVI) and difference index (DI) were defined to quantify the variation of vegetation–climate response relationship before and after water impoundment. The results show that water impoundment might have some impacts on the response of vegetation–climate, which gradually reduced with increasing distance from the channel; comparing with the residual analysis method, the SI and DI index methods are more intuitive, and combining these two methods may provide new ideas for the study of the impact of human activities on vegetation.

The Discharge Outlets Layout Optimization of Typical River Section in the Three Gorges Reservoir Area

2014 ◽  
Vol 955-959 ◽  
pp. 3287-3294
Author(s):  
Zheng Wang ◽  
Ying Liu
Keyword(s):  
Water Quality ◽  
Three Gorges Reservoir ◽  
Three Gorges Reservoir Area ◽  
Three Gorges ◽  
Mixing Zone ◽  
Unit Load ◽  
Reservoir Area ◽  
The Three Gorges Reservoir ◽  
The Three Gorges ◽  
The Impact

To improve water quality and alleviate pollution in Changshou-Fuling section of the Three Gorges Reservoir Area, an analysis methodology of regional key discharge outlet based on hydrodynamic-water quality model was developed. The EFDC model was used to study the impact of different discharge outlets on the transport of contamination in the study area by using the concept of pollutant mixing zone and pollutant mixing zone per unit load. Model calibration was conducted using observed data in 2008. Results indicated that EFDC could perfectly simulate hydrodynamics characteristics and contaminant transport process. Calculated results of pollutant mixing zone per unit load showed that the discharge outlet location in Fuling is more reasonable than that in Changshou. This study provides useful information for optimization of discharge outlets location and prediction of pollutant mixing zone in the study area, which is important for the government to make water pollution control measures.

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.

scholarly journals Characteristics of carbon source greenhouse gas flux in the water–air formation in the middle and upper reaches of the Three Gorges Reservoir

Water Policy ◽  
2021 ◽  
Author(s):  
Yu Qin ◽  
Zongtai Yu ◽  
Yujia Gou ◽  
Zhengmian Liu
Keyword(s):  
Partial Pressure ◽  
Water Temperature ◽  
Water Body ◽  
Three Gorges Reservoir ◽  
Diffusion Flux ◽  
Estimation Method ◽  
Three Gorges Reservoir Area ◽  
Three Gorges ◽  
The Three Gorges Reservoir ◽  
The Three Gorges

Abstract This study selected five points in the middle and upper mainstream of the Three Gorges Reservoir area. Starting from May 2016, the greenhouse gases CO2 and CH4 from the water–air formation at the sampling points have been monitored month by month for 10 months. Using the headspace balance method and the thin boundary layer model estimation method, we obtained the CO2 and CH4 partial pressure ranges and the water–air formation diffusion flux at the mainstream point. It is found that the CH4 partial pressure of water body is significantly positively correlated with water temperature, and significantly negatively correlated with DO; the CH2 partial pressure of water body is positively correlated with water temperature, but negatively correlated with conductivity, DO, pH and wind speed. The diffusion fluxes of CH4 and CO2 at the water–air formation are positively correlated with CH4 partial pressure and water temperature, and negatively correlated with ph, DO and conductivity. It is also found that the reservoir has a certain mitigation effect on the release of CO2 from the river water body, and the CH4 diffusion flux at the water–air formation is roughly equivalent.

scholarly journals The Impact Analysis of Water Body Landscape Pattern on Urban Heat Island: A Case Study of Wuhan City

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Bohan Yang ◽  
Fen Meng ◽  
Xinli Ke ◽  
Caixue Ma
Keyword(s):  
Water Body ◽  
Impact Analysis ◽  
Remote Sensing Technique ◽  
Multiple Stepwise Regression Analysis ◽  
Average Water ◽  
Urban Heat ◽  
City Water ◽  
The Impact ◽  
The Relationship

Based on the LST and the landscape metrics of water body with remote sensing technique and spatial analysis, the relationship between the mean LST and the attributes of water body was revealed via Pearson’s correlation analysis and multiple stepwise regression analysis. Result showed that, in 32 class-based metrics we selected, the proportion of water body, average water body size, the isolation and fragmentation of water body, and other eight metrics have high correlation with the LST. As a resultant force, the quantity, shape, and spatial distribution of water body affect the forming of temperature. We found that the quantity and spatial pattern of city water body could be allocated reasonably to maximize its cooling effect.

scholarly journals Evolution and Prediction of Landscape Pattern and Habitat Quality Based on CA-Markov and InVEST Model in Hubei Section of Three Gorges Reservoir Area (TGRA)

2018 ◽  
Vol 10 (11) ◽  
pp. 3854 ◽  
Author(s):  
Lin Chu ◽  
Tiancheng Sun ◽  
Tianwei Wang ◽  
Zhaoxia Li ◽  
Chongfa Cai
Keyword(s):  
Habitat Quality ◽  
Landscape Pattern ◽  
Quality Index ◽  
Three Gorges Reservoir ◽  
Habitat Degradation ◽  
Three Gorges Reservoir Area ◽  
Three Gorges ◽  
Invest Model ◽  
Pattern Dynamics ◽  
The Impact

The spatial pattern of landscape has great influence on the biodiversity provided by ecosystem. Understanding the impact of landscape pattern dynamics on habitat quality is significant in regional biodiversity conservation, ensuring ecological security guarantee, and maintaining the ecological environmental sustainability. Here, combining CA-Markov and InVEST model, we investigated the evolution of landscape pattern and habitat quality, and presented an explanation for variability of biodiversity linked to landscape pattern in Hubei section of Three Gorges Reservoir Area (TGRA). The spatial-temporal evolution characteristic of landscape pattern from 1990 to 2010 were analyzed by Markov chain. Then, the spatial pattern of habitat quality and its variation in three phases were computed by InVEST model. The driving force for landscape variation was explored by using Logistic regression analysis. Next, the CA-Markov model was used to simulate the future landscape pattern in 2020. Finally, future habitat quality maps were obtained by InVEST model predicted landscape maps. The results concluded that, the overall landscape pattern has changed slightly from 1990 to 2010. Woodland, waters and construction land had the greatest variations in proportion among the landscape types. The area of woodland has been decreasing gradually below the average elevation of 140 m, and the area of waters and construction land increased sharply. Logistics regression results indicated that terrain and climate were the most influencing natural factors compared with human factors. The Kappa coefficient reached 0.92, indicating that CA-Markov model had a good performance in future landscape prediction by adding nighttime light data as restriction factor. The biodiversity has been declining over the past 20 years due to the habitat degradation and landscape pattern variation. Overall, the maximum values of habitat degradation index were 0.1188, 0.1194 and 0.1195 respectively, showing a continuously increasing trend from 1990 to 2010. Main urban areas of Yichang city and its surrounding areas has higher habitat degradation index. The average values of habitat quality index of the whole region were 0.8563, 0.8529 and 0.8515 respectively, showing a continuously decreasing trend. The lower habitat quality index mainly located in the urban land as well as the main and tributary banks of the Yangtze River. Under the business as usual scenario, habitat quality continued to maintain the variation trend of the previous decade, showing a reducing habitat quality index and an increasing area of artificial surface. Under the ecological protection scenario, the variation of habitat quality in this scenario represented reverse trend to the previous decade, exhibiting an increase of habitat quality index and an increasing area of woodland and grassland. Construction of Three Gorges Dam, impoundment of Three Gorges Reservoir (TGR), resettlement of Three Gorges Project and urbanization were the most explanatory driving forces for landscape variation and degradation of habitat quality. The research may be useful for understanding the impact of landscape pattern dynamics on biodiversity, and provide scientific basis for optimizing regional natural environment, as well as effective decision-making support to local government for landscape planning and biodiversity conservation.

Productive Experiment of Combined Process Treating Sewage of Three Gorges Reservoir Region

2011 ◽  
Vol 90-93 ◽  
pp. 2444-2450
Author(s):  
Xiao Xia Ma ◽  
Lei Huang ◽  
Jing Song Guo
Keyword(s):  
Three Gorges Reservoir ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Domestic Sewage ◽  
Three Gorges ◽  
Removal Rates ◽  
Combined Process ◽  
Effluent Concentration ◽  
Three Gorges Reservoir Region ◽  
The Impact

To investigate the domestic sewage treatment processes fitting for small mountain towns in Three Gorges Reservoir Region, a demonstration project was built to treat domestic sewage which combined with anaerobic hydrolysis, natural water-dropping aeration and improved artificial soil rapid infiltration and was based on the features of large terrain elevation and many barren ravines. Changes of major pollutants were analyzed in the combined process. The impact of temperature and influent loadings on removal rates of pollutants was investigated. The results showed that, the treatment system had a strong resistance to the influent loadings with good removal rates of pollutants. There was a relationship between temperature and the removal rates of chemical oxygen demand, ammonia and total nitrogen in the system, where the removal rate of total phosphorus was not associated with temperature. There was a clear linear relationship between effluent concentration and influent loadings, effluent concentration increased with influent loadings. There were approximate logarithmic relationships between removal loadings per unit area and influent loadings.

Soil erosion in the Three Gorges Reservoir area

Soil Research ◽  
2011 ◽  
Vol 49 (3) ◽  
pp. 212 ◽  
Author(s):  
Xibao Xu ◽  
Yan Tan ◽  
Guishan Yang ◽  
Hengpeng Li ◽  
Weizhong Su
Keyword(s):  
Soil Erosion ◽  
Three Gorges Reservoir ◽  
Storage Period ◽  
Three Gorges Reservoir Area ◽  
Three Gorges ◽  
Reservoir Area ◽  
Modis Ndvi ◽  
The Three Gorges Reservoir ◽  
The Three Gorges ◽  
The Impact

Spatial and temporal change in soil erosion in the Three Gorges Reservoir area since the water storage of the reservoir began filling to 135 m in 2003 is poorly understood. Using a modified soil erosion model, this study quantifies and analyses change in the extent and intensity of soil erosion in the region from 2000 to 2008. MODIS-NDVI remote sensing data (with 250 m spatial resolution) are used in the modelling and analysis of the study. The total amount, area, and intensity of soil erosion in the reservoir region presented a declining trend from 2000 to 2008. Yet there was an anomaly in the trend, in which extreme soil erosion occurred in 2003 and lasted until 2005. The average volume of soil erosion per year decreased by 4.10 × 106 t and the mean area of land experiencing soil erosion reduced by 1129.6 km2 from the pre-storage period (2000–02) to post-storage period II (2006–08). Land suffering soil erosion at high, very high, and severe levels mainly comprises forest and cropland on slopes with gradients ≥15° and is largely distributed in the eastern and south-western sections of the reservoir area. Land experiencing soil erosion at slight or moderate levels mainly involves cropland and forest on slopes with gradients ≥10° in the central section of the reservoir area. The impact of the Three Gorges Project on soil erosion since 2000 has been mainly mediated through three mechanisms: near-resettlement of rural and urban people; increased frequency and severity of geological hazards induced by rising storage of the reservoir; and implementation of ecological projects in the region. Through the former two mechanisms, soil erosion in the affected communities has been exacerbated, while the ongoing ecological projects appear to offset both the extent and intensity of soil erosion in the reservoir region. Other important factors influencing soil erosion include urban reconstruction and expansion, varying intensity of precipitation, and soil degradation.

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