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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

Redox history of the Three Gorges region during the Ediacaran and Early Cambrian as indicated by the Fe isotope

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Geoscience Frontiers 2018年第1期9卷 155-172页

作者： Yusuke Sawaki Miyuki Tahata Tsuyoshi Komiya Takafumi Hirata Jian Han Degan Shu Department of Earth and Planetary Sciences Tokyo Institute of Technology Department of Earth Science and Astronomy Graduate School of Arts and Sciences The University of Tokyo Geochemistry Research Center The University of Tokyo Department of Geology and Key Laboratory for Continental Dynamics Northwest University

The Ediacaran-Cambrian transition is characterized by numerous events such as the emergence of large multi-cellular metazoans and surface environmental disturbances.Based on geological evidence,it has been proposed that this transition coincided with the increase in the atmospheric oxygen level that was key to the evolution of life.Even though ancient redox conditions can be inferred from the composition of sedimentary iron mineral species,this method is not necessarily applicable to all rocks.In the Earth system,the cycling of iron is of considerable interest owing to its sensitivity to redox conditions.Information regarding the paleo-oceanic iron cycle is revealed in the iron isotopic composition of ironbearing minerals.Unfortunately,only limited iron isotopic data exists for Ediacaran-to Cambrianperiod oceans.To circumvent this deficiency,we drilled a fossiliferous Ediacaran to Early Cambrian sedimentary succession in the Three Gorges region,South China.We analyzed the iron isotope ratios(δ^(56/54)Fe)of pyrite grains in the drill cores using laser ablation multi collector inductively coupled plasma mass spectrometry.The results demonstrate large variations inδ^(56/54)Fe,from-1.6 to 1.6‰,and positive iron isotope ratios are observed in many successions.The presence of positiveδ^(56/54)Fe in pyrite indicates that the ferrous iron in the seawater was partially oxidized,suggesting that seawater at Three Gorges was ferruginous during the Ediacaran and Early Cambrian periods.However,aggregated pyrite grains in organic carbon-rich black shales at Member 4 of the Doushantuo Formation and the base of the Shuijingtuo Formation yield near-zeroδ^(56/54)Fe values;this suggests that the ocean was transiently dominated by sulfidic conditions during these periods.Notably negativeδ^(56/54)Fe values,lower than-1‰,can be interpreted as a signature of DIR.The DIR also might contribute in part to the re-mineralization of organic matter during the largest negative carbon isotope anomaly in the Ediacaran.

关键词： δ56/54Fe Pyrite Ediacaran Cambrian Three Gorges

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

Influence of the Three Gorges Dam on schistosomiasis control in the middle and lower reaches of the Yangtze River

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Global Health Journal 2019年第1期3卷 9-15页

作者： Shiqing Zhang Tianping Wang Yibiao Zhou Zhiguo Cao Guangming Zhang Na Wang Qinwu Jiang Anhui Provincial Institute of Schistosomiasis Control 377Wuhu RoadHefei 230061China School of Public Health Fudan University130Dong'an RoadXuhui DistrictShanghai 200032China

This paper summarizes the factors affecting schistosomiasis transmission in the middle and lower reaches of the Yangtze River before and after the completion of the Three Gorges Dam and analyzes schistosomiasis prevalence trends to provide a basis for the application of the Three Gorges project methodologies in other areas.The Three Gorges Dam has demonstrated a positive effect on schistosomiasis control.Hubei,Hunan,Jiangxi,Anhui,and Jiangsu in the middle and lower reaches of the Yangtze River are currently regions with a high prevalence of schistosomiasis.These five provinces contained 97.62% of known snail areas and 93.66% of calculated schistosomiasis cases with 90.07% of counties (cities,districts) not yet meeting the criteria for schistosomiasis transmission interruption by the end of 2016.After the Three Gorges Dam was built,the prevalence of schistosomiasis in the middle and lower reaches of the Yangtze River decreased.By the end of 2016,the estimated number of cases decreased by 92.75% and the snail habitat areas decreased by 6.56% compared to 2004.No acute schistosomiasis cases have occurred for two consecutive years since 2015.

关键词： Three Gorges Dam Schistosomiasis control Influence Prevalence of schistosomiasis Oncomelania snail The Yangtze River

Spatiotemporal features of farmland scaling and the mechanisms that underlie these changes within the Three Gorges Reservoir Area

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Journal of Geographical Sciences 2019年第4期29卷 563-580页

作者： LIANG Xinyuan LI Yangbing School of Geography and Tourism Chongqing Normal UniversityChongqing 401331China Key Laboratory of Surface Process and Environment Remote Sensing in the Three Gorges Reservoir Area Chongqing 401331China

Discussions regarding the functional transformation of agricultural utilization and the mechanisms that underlie these changes within the Three Gorges Reservoir Area(TGRA)reflect variati ons in the relati on ship betwee n people and their environme nt in China's central and wester ns part,an area of mountains and reservoirs.A clear understa nding of these changes also provides the scientific basis for the development of multi-functional agriculture in typical mountainous areas.Five counties were selected for analysis in this study from the hinterland of the TGRA;we analyzed changes in farmland scaling and corresponding under?lying mechanisms by defining the concepts of“Scaling Farmland”(SF)and by using the software packages ArcGIS10.2,SPSS,and Geographical Detectors.The results of this analysis show that sources of increased SF have mainly comprised cultivated and shrub land.In deed,with the excepti on of some alpine off-season vegetables,SF growth has mainly occurred in low altitude areas and in places where the slope is less than 30°.We also show that spatial changes in various SF types have also been substantially different,but in all cases are closely related to road and township administrative centers.Natural factors at the patch level,including elevation and slope,have contributed significantly to SF,while at the township level,underlying socioeconomic and humanistic factors have tended to include road traffic and agricultural population density.In contrast,at the region al level,underlying driving forces within each have tended to be more significant than overall study area scale.We show that while changes in,and the development of,SF have been driven by numerous factors,agri?cultural policies have always been amongst the most important.The results clearly elucidate general land use transformation patter ns within the mountain regi ons of western China.

关键词： Three Gorges Reservoir Area functional transformation of agricultural land scaling farmland spatiotemporal features underlying driving forces

Water level variation characteristics under the impacts of extreme drought and the operation of the Three Gorges Dam

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Frontiers of Earth Science 2019年第3期13卷 510-522页

作者： Yuanfang CHAI Yitian LI Yunping YANG Sixuan LI Wei ZHANG Jinqiu REN Haibin XIONG State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072China Key Laboratory of Engineering Sediment Tianjin Research Institute for Water Transport EngineeringMinistry of TransportTianjin 300000China

Under the influence of a climate of extreme drought and the Three Gorges Dam (TGD) operation, the water levels in the middle and lower reaches of the Yangtze River in 2006 and 2011 changed significantly compared with those in the extreme drought years of 1978 and 1986. To quantitatively analyze the characteristics of water level variations in 2006 and 2011, a new calculation method was proposed, and the daily water level and discharge from 1955-2016 were collected in this study. The findings are as follows: in 2006 and 2011, the water level in the dry season significantly increased, but that in the flood season obviously decreased compared with the levels in 1978 and 1986. Here, we described this phenomenon as “no low-water-level in dry season, no high-water-level in flood season”. Based on the calculation method, the contributions of climate variability and the Three Gorges Dam operation to water level variations in the middle and lower reaches of the Yangtze River were calculated, and the contributions indicated that climate variability was the main reason for the phenomenon of “no low-water-level in diy season, no high-water-level in flood season” instead of flood peak reduction in the flood season and drought runoff implementation in the dry season, which are both induced by TGD.

关键词： water level extreme drought climate the Three Gorges Dam the Yangtze River Basin

Daily optimized model for long-term operation of the Three Gorges-Gezhouba Cascade Power Stations

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Science China(Technological Sciences) 2007年第z1期50卷 98-110页

作者： CAO GuangJing1, CAI ZhiGuo1?, LIU ZhiWu1 & WANG GuangQian2 1 China Three Gorges Project Corporation, Yichang 443002, China 2 State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, China Institut fur CHemie FU BerlinTakustr.3D-14195 BerlinGermany China Three Gorges Project Corporation Yichang 443002 China

This paper presents the step-by-step genetic algorithm based on artificial intelligence guidance and builds a long-term daily optimized operating model for the Three Gorges-Gezhouba Hydropower Complex with single generating set as the based operating unit. Actual operating data from 2004 to 2006 are used to verify the model, and results show that the simulation accuracy determined by measuring the total amount of cascade power generation reaches 99.66%. Statistic hydrological data of normal years and actual data of three years of 2004―2006 are respectively used to perform an optimized prediction of the power generation process and benefits in future when the water stored in the TGP Reservoir reaches 175 m level and power generation benefits under different operation modes, such as delayed subsiding water level, advance water storage, and adopting of different flood-limited water levels, are forecasted. In the case of years with normal inflows, the total amount of cascade power generation running on current specifications reaches 107500 GWh per year. If the commencement of water storage after the flood season is moved forward by 20 days, the amount of power generation can be increased by 3400 GWh per year. If the limited water level in the flood season is raised by three to five meters, the amount of power generation can be increased by 1600 to 3200 GWh per year. If the commencement of water storage is moved forward while the maximum water level allowed in the flood season is raised, the amount of power generation can be increased by 6400 GWh per year.

关键词： cascade operation Three Gorges Project genetic algorithm optimization forecast

Application of the Double-difference Relocation Method Combined with Waveform Cross-correlation on the Three Gorges Reservoir Seismicity

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Earthquake Research in China 2017年第3期31卷 368-380页

作者： Luo Jiahong Ma Wentao Li Chunzheng Key Laboratory of Active Tectonics and Volcano Institute of GeologyCEABeijing 100029China

In this paper,we use the double difference location method based on waveform crosscorrelation algorithm for precise positioning of the Three Gorges Reservoir( TGR)earthquakes and analysis of seismic activity. First,we use the bi-spectrum cross-correlation method to analyze the seismic waveform data of TGR encrypted networks from March,2009 to December,2010,and evaluate the quality of waveform cross-correlation analysis.Combined with the waveform cross-correlation of data obtained, we use the double difference method to relocate the earthquake position. The results show that location precision using bi-spectrum verified waveform cross-correlation data is higher than that by using other types of data,and the mean 2 sig-error in EW,NS and UD are 3.2 m,3.9 m and 6.2 m,respectively. For the relocation of the Three Gorges Reservoir earthquakes,the results show that the micro-earthquakes along the Shenlongxi river in the Badong reservoir area obviously show the characteristics of three linear zones with nearly east-west direction,which is in accordance with the small faults and carbonate strata line of the neotectonic period,revealing the reservoir water main along the underground rivers or caves permeated and induced seismic activity. The stronger earthquakes may have resulted from small earthquakes through the active layers.

关键词： Bi-spectrum verification Waveform cross-correlation Double-difference location The Three Gorges Reservoir