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Spatial-temporal variations of natural suitability of human settlement environment in the Three gorges Reservoir Area A case study in Fengjie County,China

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Frontiers of Earth Science 2019年第1期13卷 1-17页

作者： Jieqiong LUO Tinggang ZHOU Peijun DU Zhigang XU Key Laboratory for Satellite Mapping Technology and Applications of State Administration of Surveying Mapping and Geoinformation of China Nanjing UniversityNanjing 210023China Jiangsu Provincial Key Labomtory of Geographic Information Science and Technology Nanjing UniversityNanjing 210023China Jiangsu Center for CoUabomtive Innovation in Geographical Information Resource Development and Application Nanjing 210023China School of Geographical Sciences Southwest UniversityChongqing 400715China Key Laboratory of Eco-environments in Three gorges Reservoir Region (Ministry of Education) Chongqing 400715China

With rapid environmental degeneration and socio-economie development,the human settlement environment (HSE)has experienced dramatic changes and attracted attention from different communities.Consequently,the spatial-temporal evaluation of natural suitability of the human settlement environment (NSHSE)has become essential for understanding the patterns and dynamics of HSE,and for coordinating sustainable development among regional populations,resources,and environments.This study aims to explore the spatialtemporal evolution of NSHSE patterns in 1997,2005,and 2009 in Fengjie County near the Three gorges Reservoir Area (TGRA).A spatially weighted NSHSE model was established by integrating multi-source data (e.g.,census data,meteorological data,remote sensing images,DEM data,and GIS data)into one framework,where the Ordinary Least Squares (OLS)linear regression model was applied to calculate the weights of indices in the NSHSE model.Results show that the trend of natural suitability has been first downward and then upward, which is evidenced by the disparity of NSHSE existing in the south,north,and central areas of Fengjie County. Results also reveal clustered NSHSE patterns for all 30 townships.Meanwhile,NSHSE has significant influence on population distribution,and 71.49% of the total population is living in moderate and high suitable districts.

关键词： natural suitability of human settlement environment ordinary least squares model global and local spatial autocorrelation analyses Three gorges Reservoir Area (TGRA) Fengjie Cotmty

Possibilities and challenges of expanding dimensions of waterway downstream of Three gorges Dam

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Water Science and Engineering 2019年第2期12卷 136-144页

作者： Tao Yan Yun-ping Yang Yi-bing Li Yuan-fang Chai Xiao-bing Cheng Key Laboratory of Yellow River Sediment Research Ministry of Water ResourcesZhengzhou 450003China Key Laboratory of Engineering Sediment Tianjin Research Institute for Water Transport EngineeringMinistry of TransportTianjin 300456China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072China

The waterway in the middle and lower reaches of the Yangtze River has long been known as the Golden Waterway and has served as an important link in the construction of the Yangtze River Economic Belt.Therefore,expanding its dimensions is a significant goal,particularly given the long-range cumulative erosion occurring downstream of the Three gorges Dam (TGD),which has been concentrated in the dry river channel.With the regulation of the volume from upstream reservoirs and the TGD,the minimum discharge and water level of the river downstream are increasing,and creating favorable conditions for the increase of the depth of the waterway.The discharge compensation effect during the dry season offsets the decline in the water level of the river channel caused by the down-cutting of part of the riverbed,but the minimum navigable water level of the segment near the dam still shows a declining trend.In recent years,several waterway remediation projects have been implemented in the downstream reaches of the TGD and although the waterway depth and width have been increased,the channel dimensions are still insufficient in the Yichang-Anqing reach (with a total length of 1026 km),as compared to the upstream reservoir area and the deep water channel in the downstream tidal reaches.A comprehensive analysis of the water depth and the number and length of shoals in the waterway indicates that its dimensions can be increased to 4.5 m ×200 m and 6.0 m×200 m in the Yichang-Wuhan and Wuhan-Anqing reaches,respectively.This is also feasible given the remediation technologies currently available,but remediation projects need to be coordinated with those for flood prevention and ecological protection.

关键词： Waterway dimension Condition analysis Three gorges Project Yichang-Anqing reach Yangtze River

P wave velocity structure of upper and middle crust beneath the Three gorges reservoir dam and adjacent regions

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Science China Earth Sciences 2009年第4期52卷 567-578页

作者： LI Qiang ZHAO Xu CAI JinAn LIU RuiFeng LONG GuiHua AN YanRu National Earthquake Infrastructure Service China Earthquake AdministrationBeijing 100037China China Earthquake Network Center China Earthquake AdministrationBeijing 100045China Institute of Earthquake Science China Earthquake AdministrationBeijing 100036China Institute of Geology and Geophysics Chinese Academy of SciencesBeijing 100029China

The three-dimensional P wave velocity structures of upper and middle crust beneath the Three gorges reservoir dam and adjacent regions were reconstructed by means of the seismic tomography, using the absolute P-arrivals from the events observed by the Three gorges seismic network. Our preliminary study of the deep structure shows: (1) the lithology of the Huangling anticline, integral and highly so-lidified, exhibits a uniformity. Down to a depth of 20 km, the Huangling anticline still shows high- velocity anomalies. Note that the characteristics of the velocity images with the different depths are not the same; (2) the depth of the sedimentary rocks beneath the entire Zigui basin is not constant, which is less than 6 km; (3) the top boundary of the crystalline basement varies from 0 to 7 km, whereas the bottom one between 14 and 16 km; (4) the partially molten substances of the upper mantle are located in the Badong-Zigui and its adjacent regions as well as nearby Peishi area. The development and evo-lution of the current tectonics are associated with the cooling and solidifying process of the molten substances within the upper mantle; (5) the different velocity structures of the deep crust in both east and west side of the Jiuwanxi fault are to be investigated in order to understand the origin of gravita-tional gradient zone in the Three Gorge areas; and (6) the velocities within the upper crust would be affected by reservoir water permeability.

关键词： Three gorges reservoir upper and middle crust three-dimensional velocity structure

Flood management of Dongting Lake after operation of Three gorges Dam

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Water Science and Engineering 2017年第4期10卷 303-310页

作者： Xi-jun Lai Zi-ming Wang Key Laboratory of Watershed Geographic Sciences Nanjing Institute of Geography&LimnologyChinese Academy of Sciences(CAS)Nanjing 210008China Zhejiang Institute of Hydraulics and Estuary Hangzhou 310020Chin

Full operation of the Three gorges Dam(TGD) reduces flood risk of the middle and lower parts of the Yangtze River Basin. However,Dongting Lake, which is located in the Yangtze River Basin, is still at high risk for potentially severe flooding in the future. The effects of the TGD on flood processes were investigated using a hydrodynamic model. The 1998 and 2010 flood events before and after the operation of the TGD, respectively, were analyzed. The numerical results show that the operation of the TGD changes flood processes, including the timing and magnitude of flood peaks in Dongting Lake. The TGD can effectively reduce the flood level in Dongting Lake, which is mainly caused by the flood water from the upper reach of the Yangtze River. This is not the case, however, for floods mainly induced by flood water from four main rivers in the catchment. In view of this, a comprehensive strategy for flood management in Dongting Lake is required. Non-engineering measures, such as warning systems and combined operation of the TGD and other reservoirs in the catchment, as well as traditional engineering measures, should be further improved. Meanwhile, a sustainable philosophy for flood control, including natural flood management and lake restoration, is recommended to reduce the flood risk.

关键词： Three gorges Dam Flood control Water level Hydrodynamic model Dongting Lake

Displacement characteristics and prediction of Baishuihe landslide in the Three gorges Reservoir

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Journal of Mountain Science 2019年第9期16卷 2203-2214页

作者： LI De-ying SUN Yi-qing YIN Kun-long MIAO Fa-sheng Thomas GLADE Chin LEO Faculty of Engineering China University of Geosciences Wuhan 430074 China Department of Geography and Regional Research University of Vienna Vienna 1010 Austria School of Computing Engineering and Math Western Sydney University Sydney NSW 1797 Australia

In order to reach the designated final water level of 175 m, there were three impoundment stages in the Three gorges Reservoir, with water levels of 135 m, 156 m and 175 m. Baishuihe landslide in the Reservoir was chosen to analyze its displacement characteristics and displacement variability at the different stages. Based on monitoring data, the landslide displacement was mainly influenced by rainfall and drawdown of the reservoir water level. However, the magnitude of the rise and drawdown of the water level after the reservoir water level reached 175 m did not accelerate landslide displacement. The prediction of landslide displacement for active landslides is very important for landslide risk management. The time series of cumulative displacement was divided into a trend term and a periodic term using the Hodrick-Prescott(HP) filter method. The polynomial model was used to predict the trend term. The extreme learning machine(ELM) and least squares support vector machine(LS-SVM) were chosen to predict theperiodic term. In the prediction model for the periodic term, input variables based on the effects of rainfall and reservoir water level in landslide displacement were selected using grey relational analysis. Based on the results, the prediction precision of ELM is better than that of LS-SVM for predicting landslide displacement. The method for predicting landslide displacement could be applied by relevant authorities in making landslide emergency plans in the future.

关键词： Landslide Three gorges Reservoir Impoundment process Displacement prediction

Assessing the spatiotemporal distributions of evapotranspiration in the Three gorges Reservoir Region of China using remote sensing data

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Journal of Mountain Science 2018年第12期15卷 2676-2692页

作者： MA Ze-zhong RAY Ram L HE Yi-ping Chongqing Institute of Surveying and Planning for Land Resource and Housing Chongqing 400020China Cooperative Agricultural Research Center College of Agriculture and Human SciencesPrairie View A&M UniversityPrairie ViewTX 77446USA EDF Renewal Energy San DiegoCA 92118USA

Evapotranspiration(ET) is a critical component of the global hydrological cycle, and it has a large impact on water resource management as it affects the availability of freshwater resources. It is important to understand the hydrological cycle for the water resources planning and management. This study used Moderate Resolution Imaging Spectroradiometer(MODIS) satellite derived ET, and potential evapotranspiration(PET) and Tropical Rainfall Measuring Mission(TRMM) satellite derived precipitation datasets to assess the spatial and temporal distributions of ET, PET, and precipitation during the study period at Three gorges Reservoir(TGR) region. Based on the topographic variations and land-use/land-cover distributions, the study region which includes five counties of Hubei Province and nineteen counties of Chongqing Municipality was divided into four study zones. The ET and precipitation data were evaluated using in situ observations. The ET, PET, and precipitation data were compared to analyze the spatial and long-term(2001-2016) temporal distributions of average annual ET, PET, and precipitation, and to understand the relationships between them in the study region. The results showed that each selected zone had highest ET at the counties with the Yangtze River passing through whereas lowest at the counties which were located away from the river. Results also showed increasing trends in ET and PET from south-west to north-east in the study region. Analysis showed TGR had a significant impact on spatial and temporal distributions of ET and PET in the study region. Therefore, this study helps to understand the impact of TGR on spatial and temporal distributions of ET and PET during and after the construction.

关键词： Evapotranspiration Precipitation Tropical Rainfall Measuring Mission (TRMM) Moderate Resolution Imaging Spectroradiometer (MODIS) Three gorges Reservoir Potential Evapotranspiration

Mapping landslide susceptibility at the Three gorges Reservoir, China, using gradient boosting decision tree,random forest and information value models

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Journal of Mountain Science 2020年第3期17卷 670-685页

作者： CHEN Tao ZHU Li NIU Rui-qing TRINDER C John PENG Ling LEI Tao Institute of Geophysics and Geomatics China University of GeosciencesWuhan 430074China Geomatics Technology and Application key Laboratory of Qinghai Province Xining 810001China School of Civil and Environmental Engineering The University of New South WalesSydneyNSW 2052Australia China Institute of Geo-Environment Monitoring Beijing 100081China School of Electronical and Information Engineering Shaanxi University of Science and TechnologyXi’an 710021China

This work was to generate landslide susceptibility maps for the Three gorges Reservoir(TGR) area, China by using different machine learning models. Three advanced machine learning methods, namely, gradient boosting decision tree(GBDT), random forest(RF) and information value(InV) models, were used, and the performances were assessed and compared. In total, 202 landslides were mapped by using a series of field surveys, aerial photographs, and reviews of historical and bibliographical data. Nine causative factors were then considered in landslide susceptibility map generation by using the GBDT, RF and InV models. All of the maps of the causative factors were resampled to a resolution of 28.5 m. Of the 486289 pixels in the area,28526 pixels were landslide pixels, and 457763 pixels were non-landslide pixels. Finally, landslide susceptibility maps were generated by using the three machine learning models, and their performances were assessed through receiver operating characteristic(ROC) curves, the sensitivity, specificity,overall accuracy(OA), and kappa coefficient(KAPPA). The results showed that the GBDT, RF and In V models in overall produced reasonable accurate landslide susceptibility maps. Among these three methods, the GBDT method outperforms the other two machine learning methods, which can provide strong technical support for producing landslide susceptibility maps in TGR.

关键词： Mapping landslide susceptibility Gradient boosting decision tree Random forest Information value model Three gorges Reservoir

Grey Prediction of Seismic Activity in the Three gorges Area of the Yangtze River

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Acta Geologica Sinica(English Edition) 1999年第3期73卷 294-299页

作者： HU Daogong WU Shuren TAN Chengxuan Institute of Geomechanics CAGS Beijing 100081

On the basis of historical earthquake data and recent observations, two grey models prediction of the next seismic active period and the maximal magnitude of earthquakes which might occur during that period are constructed on the basis of the grey theory. As predicted by the two models, the next seismic active period would last 79 years, and that the maximal magnitude of earthquakes occurring within the period would not exceed 5.2. These results provide an important basis for the assessment of earthquake risks and reduction of disasters in the Three gorges area.

关键词： grey theory seismicity peak period magnitude Three gorges area Yangtze River

Fractal characterization of sediment particle-size distribution in the water-level fluctuation zone of the Three gorges Reservoir, China

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Journal of Mountain Science 2019年第9期16卷 2028-2038页

作者： LI Jin-lin BAO Yu-hai WEI Jie HE Xiu-bin TANG Qiang Jean de Dieu NAMBAJIMANA Key Laboratory of Mountain Surface Processes and Ecological Regulation Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 China Chongqing Key Laboratory of Earth Surface Processes and Environmental Remote Sensing in the Three gorges Reservoir Area Chongqing 401331 China University of Chinese Academy of Sciences Beijing 100049 China Sustainable Agriculture Sciences Department Rothamsted Research North Wyke Okehampton Devon EX20 2SB UK

The combined effect of periodic water impoundment and seasonal natural flood events has created a 30 m high water-level fluctuation zone(WLFZ) around the Three gorges Reservoir(TGR), China, forming a unique eco-landscape. Siltation, eutrophication, enrichment of heavy metals, and methane emissions in the WLFZ have been widely associated with sediment and soil particles generated from the upstream catchment or upland slopes. However, little attention has been paid to the complexity of sediment particle-size distributions in the WLFZ. In the present study, core samples(from a 345 cm thick sediment core from the base of the WLFZ), slope transect surface samples(across/up a WLFZ slope), and along-river/longitudinal surface samples(from the reservoir reaches) were collected. Laser granulometry and a volume-based fractal model were used to reveal the characteristics of sediment particle-size distributions. Results indicate that the alternation of coarse and fine particles in the sedimentary core profile is represented as a fluctuation of low and high values of fractal dimension(D), ranging from 2.59 to 2.77. On the WLFZ slope transect, surface sediment particles coarsen with increasing elevation, sand content increases from 3.3% to 78.5%, and D decreases from 2.76 to 2.53. Longitudinally, surface sediments demonstrate a downstream-fining trend, and D increases gradually downstream. D is significantly positively correlated with the fine particle content. We conclude that D is a useful measure for evaluating sediment particle-size distribution.

关键词： Spatial differentiation Sediment particle Fractal dimension Water-level fluctuation zone Three gorges Reservoir