Characteristics,classification and ordination of riparian plant communities in the Three-Gorges areas

Sixteen different vegetation types of grassland and shrubland were selected to study the component and diversity of plant species of riparian plant communities along main channel in the Three-Gorges areas. Species richness (s), Simpson index (D), and Shannon-Weiner index (H) were used to study the biodiversity and the hierarchical classification was carried out by the methods of TWINSPAN and DCA ordination. The results showed that the components of flora were complex and dominated by the temperate type in the riparian plant communities. Species diversity was not different between the communities, but Shannon-Weiner indexes of different layers in some grassland were significantly different. TWINSPAN and DCA indicated that riparian plant communities distributed along the gradient of moisture.

Benefit evaluation of the Three-Gorges Reservoir migration by an assessment index model based on analytic hierarchy process

An assessment index model was established to evaulate the benefit of the Three-Gorges Reservoir migration through the analytical hierarchy process. Totally 43 indicators were selected to assess the impact of migration on the economic, social and ecological environmental aspects of the migration communities, with the data of the indicators of the years 1992, 1998, 2002 which represented the period of premigration, the end of the first phase migration and the end of the second phase migration, respectively. The evaluation matrix is sufficiently consistent, with a consistency ratio CR equal to 0.086 3. The assessment turned out a benefit value for the economic subsystem in the year 2004 larger than triple the value in the year 1992, indicating a remarkable economic growth in the Reservoir area. The constantly increasing value for the social subsystem reflects the stable social situations. There is a slight decline in the assessment outcome of the ecological subsystem for the year 1998, which implies enviromental conservation was given insufficient importance during that period. On the whole, the implementation of the migration project is favorable to the Reservoir region, as confirmed by the stably increasing overall evaluation value from 42.22% in 1992 to 68.81% in 2002. However, there is still much room to improve from the status quo to the target criteria.

Water Environment Pollution in Three-Gorge Reservoir Area and Treatment Technology

After the erection of Three-Gorge Reservoir, the water environment in the reservoir area will be turned into water bodies like lakes, and the self-clarification ability of water will also be much slower than ever. Now, the quality of water in most segments in upper reaches of Yangtze River cannot meet the requirements of l-ll class Environment Quality Standard (GHZB1-1999). In Yangtze River, dialing River and Wujiang River, the main indexes such as colon bacillus, nonionic ammonia, chemical oxygen demand (COD), petroleum, phenol, total phosphorus (TP), heavy metal, etc., have exceeded the standard limits. The water bodies of the reservoir area are facing serious risk of eutrophicationm. To solve that problem, a countermea-sure of multi-spot diverted treatment and separate discharge is recommended. For doing this, lots of small-scale wastewater treatment facilities employing updated activated sludge treatment technologies are to be set up. Up to now, a number of sewage treatment technologies to control eutrophication of water have been developed, which include processes of sequencing batch activated sludge (SBR), absorbing bio-degradation (AB), oxidation channel, package intermittent aeration system (PIAS), intermittent cycle extended aeration system (ICEAS), UNITANK and so on. The Effective one to be applied in the reservoir area should convey the requirements of ecological agriculture, forestry and urban planning, and be accompanied by legal support for appropriate exploitation of natural resources.

Land Use Zoning in Three-Gorge Reservoir Region:A Case Study of Fengdu County in Chongqing Municipality

Taking Fengdu County in Three-Gorge Reservoir region as an example,this paper applies the dynamic clustering analysis model, and divides land resource utilization of Fengdu County into three zones: Yangtze River valley economic zone,low mountains and hills agricultural zone,and low and middle agricultural,forestry and animal husbandry zone. It also analyzes current situation and existing problems in the land utilization of every zone,and finally puts forward corresponding recommendations.

Current Situation of Land Use in Three-gorges Reservoir Region in 2010

Land is rare natural resource.Production and construction of all sectors in a region must be based on land.Thus,overall research and analysis on current situation of land use can reveal scope,depth and reasonableness of land use,is helpful for analyzing internal mechanism land use change,and can reflect production scale,level and characteristics,and also can provide basis for optimization and adjustment of land use structure.Based on RS and GIS technologies,with the aid of TM image data of the Three-gorges Reservoir Region in 2010,the data of current situation of land use in Three-gorges Reservoir Region was obtained,and current land use situation was analyzed using geographimetrics and landscape ecology methods.Results show that since natural,social and economic conditions are different,land type diversity,combination type and location index of counties in the Three-gorges Reservoir Region are varied.In the land use diversity index,Xingshan County has the most single land use type(mainly forest land); in land use degree,Yuzhong District has the highest land use degree; in the integrated index of land use,Changshou District has the lowest integrated index of land use.This study is expected to provide reference and basis for formulating policies of protecting ecological environment of the Three-gorges Reservoir Region.

Effects of drip and flood irrigation on carbon dioxide exchange and crop growth in the maize ecosystem in the Hetao Irrigation District,China

Drip irrigation and flood irrigation are major irrigation methods for maize crops in the Hetao Irrigation District,Inner Mongolia Autonomous Region,China.This research delves into the effects of these irrigation methods on carbon dioxide(CO_(2))exchange and crop growth in this region.The experimental site was divided into drip and flood irrigation zones.The irrigation schedules of this study aligned with the local commonly used irrigation schedule.We employed a developed chamber system to measure the diurnal CO_(2)exchange of maize plants during various growth stages under both drip and flood irrigation methods.From May to September in 2020 and 2021,two sets of repeated experiments were conducted.In each experiment,a total of nine measurements of CO_(2)exchange were performed to obtain carbon exchange data at different growth stages of maize crop.During each CO_(2)exchange measurement event,CO_(2)flux data were collected every two hours over a day-long period to capture the diurnal variations in CO_(2)exchange.During each CO_(2)exchange measurement event,the biological parameters(aboveground biomass and crop growth rate)of maize and environmental parameters(including air humidity,air temperature,precipitation,soil water content,and photosynthetically active radiation)were measured.The results indicated a V-shaped trend in net ecosystem CO_(2)exchange in daytime,reducing slowly at night,while the net assimilation rate(net primary productivity)exhibited a contrasting trend.Notably,compared with flood irrigation,drip irrigation demonstrated significantly higher average daily soil CO_(2)emission and greater average daily CO_(2)absorption by maize plants.Consequently,within the maize ecosystem,drip irrigation appeared more conducive to absorbing atmospheric CO_(2).Furthermore,drip irrigation demonstrated a faster crop growth rate and increased aboveground biomass compared with flood irrigation.A strong linear relationship existed between leaf area index and light utilization efficiency,irrespective of the irrigation method.Notably,drip irrigation displayed superior light use efficiency compared with flood irrigation.The final yield results corroborated these findings,indicating that drip irrigation yielded higher harvest index and overall yield than flood irrigation.The results of this study provide a basis for the selection of optimal irrigation methods commonly used in the Hetao Irrigation District.This research also serves as a reference for future irrigation studies that consider measurements of both carbon emissions and yield simultaneously.

Three-Gorges Reservoir Area on the Yangtze River Faced with Risk of Induced Destructive Earthquakes

The Three-Gorge Water Conservancy Project on the Yangtze River started to impound water by locking gates on June 1, 2003. A swarm of more than 2000 small earthquakes suddenly occurred densely along the river section in Xinling Town north of Badong, Hubei Province, on June 7. This caused grave concern in the following years, but, with the completion of the second- and third-phase engineering construction, the water level in the reservoir will rise up to 156 m and 175 m respectively, no matter whether it can induce larger and stronger earthquakes. After an analysis of the distribution of active faults in the eastern part of the reservoir area, their intersections and capability to generate earthquakes from a seismo-tectonic viewpoint, we consider that after the reservoir impounding, two potential focal zones existing in Badong and Zigui counties may generate M 5.5 earthquake, the seismic intensity of which may reach Ⅷ. It will induce landslide bodies in the reservoir area to be reactivated and slide. The evidence is the large-scale landslide occurring on the Shazhenxi Creek river in Zigui County on June 12, 2003.

Identifying the Hydrochemical Characteristics,Genetic Mechanisms and Potential Human Health Risks of Fluoride and Nitrate Enriched Groundwater in the Tongzhou District,Beijing,North China

Fluoride and nitrate enriched groundwater are potential threats to the safety of the groundwater supply that may cause significant effects on human health and public safety,especially in aggregated population areas and economic hubs.This study focuses on the high F^(−)and NO_(3)^(−)concentration groundwater in Tongzhou District,Beijing,North China.A total of 36 groundwater samples were collected to analyze the hydrochemical characteristics,elucidate genetic mechanisms and evaluate the potential human health risks.The results of the analysis indicate:Firstly,most of the groundwater samples are characterized by Mg-HCO_(3) and Na-HCO_(3) with the pH ranging from 7.19 to 8.28 and TDS with a large variation across the range 471-2337 mg/L.The NO_(3)^(−)concentration in 38.89%groundwater samples and the F^(−)concentration in 66.67%groundwater samples exceed the permissible limited value.Secondly,F^(−)in groundwater originates predominantly from water-rock interactions and the fluorite dissolution,which is also regulated by cation exchange,competitive adsorption of HCO_(3)−and an alkaline environment.Thirdly,the effect of sewage disposal and agricultural activities have a significant effect on high NO3-concentration,while the high F^(−)concentration is less influenced by anthropogenic activity.The alkaline environment favors nitrification,thus being conducive to the production of NO_(3)^(−).Finally,the health risk assessment is evaluated for different population groups.The results indicate that high NO_(3)^(−)and F^(−)concentration in groundwater would have the largest threat to children’s health.The findings of this study could contribute to the provision of a scientific basis for groundwater supply policy formulation relating to public health in Tongzhou District.

Properties and Characterization of Two Clays Raw Material from Mountain District (West of Côte d’Ivoire) for Use in Low-Carbon Cements

This work was devoted to the study of the physico-chemical properties of two clay minerals from the Mountain District (West Côte d'Ivoire) referenced ME1 and ME2. These samples were characterized by the experimental techniques, such as X-ray diffraction (XRD), Infrared spectroscopy (IR), Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES), Differential Thermal Analysis and Thermogravimetry (DTA-TG), Brunauer, Emett and Teller method (BET), laser particle size analysis and Scanning Electron Microscope (SEM). The main results of these analyses reveal that the two clay samples mainly contain quartz (52.91% for ME1 and 51.72% for ME2), kaolinite (36.60% for ME1 and 41.6% for ME2) and associated phases, namely goethite and hematite (13.47% for ME1 and 11.00% for ME2). The specific surface values obtained for samples ME1 and ME2 are 34.78 m2/g and 29.18 m2/g respectively. The results obtained show that the samples studied belong to the kaolinite family. After calcination, they could have good pozzolanic activity and therefore be used in the manufacture of low-carbon cements.

Optimization of Agricultural Industrial Structure in Changping District of Beijing Based on Grey Relational Analysis

In the economic development of Beijing,although the share of the total amount of agricultural industry in the overall economy is relatively low,it has an important impact on the daily life of residents,social stability and the development of other industries.Changping District,as an important agricultural production base of Beijing,its agricultural development has an indispensable strategic significance for the stability and growth of the entire regional economy.Therefore,it is very important to study the structure of agricultural industry in Changping District.Based on the detailed analysis of the agricultural industrial structure of Changping District,this paper uses the grey relation theory to analyze the different industries in the agricultural industrial structure of Changping District,including planting,forestry,animal husbandry,fishery and agricultural,forestry,service industries,in order to reveal the impact of these industries on the agricultural industrial structure of Changping District.Through this study,it comes up with specific and feasible suggestions for the optimization of agricultural industrial structure in Changping District,and provides valuable reference for the agricultural development of other areas in Beijing.

Improving the Quality of Public Space in Old Residential Areas Based on Superposition and Intervention:A Case Study of Baihuazhou District of Nanchang City

With the development of cities,China has entered an era of stock planning.The functions of old residential areas in urban development can no longer meet the needs of residents in the new era for a better life,and new standards have been put forward for the quality of public spaces for living.This paper analyzes and sorts out the characteristics and problems of the public space in the old residential areas of Baihuazhou district.Combining superposition and intervention techniques,the spatial,historical,cultural and other characteristic elements of the residential areas are preserved to the greatest extent.The public space in the old residential areas of Baihuazhou District is updated and reconstructed in order to achieve the goal of improving the quality of its public space.

Analysis of Characteristics and Meteorological Influencing Factors of Air Pollution in Luojiang District,Deyang City

Based on the monitoring data of ambient air quality and meteorological observation data,the characteristics and meteorological influencing factors of air pollution in Luojiang District of Deyang City from 2018 to 2022 were analyzed.The results show that from 2018 to 2022,the main air pollutants affecting the air quality of Luojiang District of Deyang City were PM_(2.5) and PM_(10),and the primary pollutant on heavy pollution days was basically PM_(2.5).PM_(2.5) and PM_(10) pollution showed obvious seasonal differences,and PM_(2.5) concentration exceeded the limit mainly in spring and winter,among which it was the most serious in early spring,especially in January and February,followed by December.PM_(10) exceeding the standard had a high seasonal correlation with PM_(2.5) exceeding the standard,mainly in spring and winter,among which it was the most serious in winter,especially in December,followed by January.PM_(2.5) and PM_(10) pollution showed an overall weakening trend.PM_(2.5) and PM_(10) concentration were closely related to meteorological factors such as temperature,relative humidity,wind speed,precipitation and air pressure,and were mainly affected by rainfall.

Soil vanadium pollution and microbial response characteristics from stone coal smelting district

A field investigation was performed to study the content, speciation and mobility of vanadium, as well as microbial response in soil from a stone coal smelting district in Hunan province of China. The results showed that the contents of soil V ranged from 168 to 1538 mg/kg, which exceeded the maximum permissible value of Canadian soil quality for V. The mean soil V content from wasteland area reached 1421 mg/kg, and those from the areas related with slag heap, ore pile and smelting center were 380, 260 and 225 mg/kg, respectively. Based on the results of the modified BCR sequential extraction procedure, V contents in the mobile fractions varied from 19.2 to 637 mg/kg accounting for 7.4%-42.3% of total V, and those of V(+5) species were between 21.9 and 534.0 mg/kg. Soil enzyme activity and microbial basal respiration were adversely affected by high level of soil V. More attention should be paid to soil V pollution and potential hazardous surrounding the stone coal smelting district.

Study on Methods of Evaluating Visual Landscapes in Historic and Cultural Districts

This paper with the purpose of protecting visual landscape environment in historical and cultural districts,analyzes categories and characteristics of historical and cultural districts from the perspective of visual landscape,finally with the assessment basis of "landscape picture" proposes the classification of areas of 5 different levels,that is,the optimal viewing gallery,the secondary viewing gallery,the optimal viewing surface,the secondary viewing surface,and the common viewing surface,explores an approach of evaluating pollution indexes in historic and cultural districts by comprehensively evaluating "landscape pictures" in those areas of different levels.

Analysis on Vapour Field for the Drought Causes in Beijing,Tianjin and Hebei Districts in Recent Years

The monthly variation,temporal-spatial distribution,transportation characteristics of vapour field at middle and lower atmosphere and their effects on drought in Beijing,Tianjin and Hebei districts were studied,which have a guiding significance on predicting climate and arranging agricultural production in the district.

Waterfront Landscape Planning along the Yihe River in the New District of Luoyang City in China

General situation of the Yihe River in the new district of Luoyang City and its evolution history were introduced and evaluated from 4 perspectives of water,embankment,vegetation and traffic accessibility.On this basis,orientation of waterfront landscape planning of the Yihe River in the overall urban planning of Luoyang City was proposed,and it was proposed that waterfront landscape planning in the study area should follow the principles of "ecological,cultural and regional,public,accessible and human-centered".It was to provide references for the landscape planning and design of the Yihe River in the new district of Luoyang City,and to promote its waterfront landscape construction.

RS and GIS-based Analysis on Dynamic Changes of Landscape Pattern on Urban-rural Fringe——A Case Study of Licheng District, Jinan City of China

By using GIS, RS and landscape ecology, LandsatTM (1993 and 2009) and ETM (2001) remote sensing images of Licheng District of Ji’nan City, Shandong Province were interpreted, and dynamic changes of landscape pattern in the district were analyzed at the levels of class and landscape. The results showed that during the 16 years the landscape pattern in the district had changed significantly. (a) From the perspective of patch category, areas of arable land, woodland and grassland decreased unceasingly, and arable land accounted for the largest reduction from 488.15 km 2 in 1993 down to 324.37 km 2 in 2009, witnessing a reduction rate of 33.56%. But the patch quantity and fragmentation increased, patch connectivity reduced. Spatial pattern of construction land expanded and its area witnessed a significant increase of 147.05%. Patch cohesion index increased and connectivity grew better. (b) From the perspective of overall landscape, patch quantity, contagion and perimeter-area fractal dimension decreased, patch shape became simple, the Shannon’s diversity index, Shannon’s evenness index and splitting index increased, landscape heterogeneity rose. With the rapid social and economic development, landscape pattern will be more and more influenced by human behaviors

Tourism Development Paths for the Leap-forward Development of Ecological Civilization—A Case Study of Northern Doumen District in Zhuhai City,China

A section more than 300 km2 in the Northern Domen District of Zhuhai City was designed to the Ecological Agricultural Zone of Zhuhai City,on the basis of introducing connotations of ecological civilization and basic conditions of this district,it was proposed that the leap-forward development pattern from agricultural civilization to ecological civilization should be applied,and 2 realization paths were summarized as developing urban agriculture and ecotourism.Ecotourism development was taken as the focus,tourist resources in the study area introduced,and bottleneck of its ecotourism development analyzed(lack of unified planning,poor consciousness of protecting historical and cultural resources;backward infrastructure,poor attractiveness for investment;insufficient propaganda and popularity;backward product development and insufficient integration of existing scenic spots.From the perspective of bottleneck of ecotourism development,the development of eco-culture and sightseeing tourism was proposed,specifically,to build a tourism spatial layout of "one axis,two wings and four centers";establish a functional circle of eco-cultural tourism,including cultural and recreational ecosphere centering on Mount Huangyang,tidal land water system ecosphere with key nodes of Dongjiao and Xijiao Villages,modern eco-agricultural sightseeing tourist circle,intangible cultural tourist circle of the waterfront Baijiao Township.

Ecological Greenway Construction in Shunde District of Foshan City,China

As the greenway construction grows popular,the concept and type of greenway is clarified in this study,research progresses and prospects of greenway planning are summarized.Greenway planning of Shunde District is taken for an example to elaborate properties,types,origination and tasks of greenway,moreover,construction background,ecological,human-centered and characteristic design principles were analyzed,especially the design of its buffer zone,corridor system,width of crawl lane,node system,identification system and service area.Greenway construction of Shunde District is to build a greenway network of multiple types and functions in 3 levels:region,city and community;a recreational landscaping system with regional greenland as the background,greennet and greenway as the framework,to promote a new "ecological,green and low-carbon" lifestyle,and create the new image of Shunde as "a livable riverfront region full of sunshine".

Comparison of two schemes for district cooling system utilizing cold energy of liquefied natural gas

Two schemes（scheme Ⅰ and scheme Ⅱ）for designing a district cooling system（DCS）utilizing cold energy of liquefied natural gas（LNG）are presented.In scheme Ⅰ,LNG cold energy is used to produce ice,and then ice is transported to the central cooling plant of the DCS.In scheme Ⅱ,return water from the DCS is directly chilled by LNG cold energy,and the chilled water is then sent back to the central plant.The heat transportation loss is the main negative impact in the DCS and is emphatically analyzed when evaluating the efficiency of each scheme.The results show that the DCS utilizing LNG cold energy is feasible and valuable.The cooling supply distance of scheme Ⅱ is limited within 13 km while scheme Ⅰ has no distance limit.When the distance is between 6 and 13 km,scheme Ⅱ is more practical and effective.Contrarily,scheme Ⅰ has a better economic performance when the distance is shorter than 6 km or longer than 13 km.