It is the core task of building a beautiful China to meet people’s needs for a beautiful ecological environment, the urban black odorous water bodies are an important source of pollution to the production, living and physical and mental health of urban residents. This study takes the urban black odorous water bodies in the Yangtze River Economic Belt as the research object, comprehensively applies GIS technology and geographic detection methods to identify its spatial structure characteristics and distribution rules, explores influential differences of different factors on the spatial patterns and proposes remediation proposals. As the study shows: (1) The spatial distribution of blacksmelly water bodies in the Yangtze River Economic Belt is in condensed distribution, and the spatial differentiation is obvious. Nuclear density is characterized by independent multiple mononuclear center, secondary centered bands and sporadic distribution; (2) The center of black odorous water bodies are in the central urban areas of Hubei provinces and Hunan provinces. Its system is obviously characterized by scaleless areas, significant fractal features and complexity of spatial structure; (3) Different types of black odorous water bodies are of positive spatial correlation, showing the different patterns of cold and hot spots with “coldness in upstream, and hotness in middle and lower reaches”; (4) The factors affecting the geographical detection of the spatial structure do not contribute significantly to the global scope, and the match of zonal influence factors is obvious. Industrial waste water discharge, domestic water consumption, drainage pipeline length, etc. are significant influencing factors; The elimination and control of the urban black odorous water bodies should be improved by strictly adhering to ecological rules, establishing urban black odorous water bodies management systems and mechanisms, improving the identification and assessment technical standards system, innovating practice renovation, and enriching theoretical research.

Promoting the construction of transportation infrastructure is of great significance to the high quality development of Min Xin Axis Belt and the promotion of coordinated regional development. Based on the data of the traffic times, the stduy analysis the network density and level, temporal accessibility,daily communication area in Min Xin Axis Belt. The results showed that: The network density of Min Xin Axis Belt increased from 12.89% to 29.94%，Wuhan, Xi ’an and Nanchang cities was been ranked the top three. Significant increase in density and intensity of contact within the railway network.The multi level railway network identifies the core structure of urban agglomeration and its organizational structure to expand.The high level railway network was coincide with the regional development strategy. The urban accessibility has been greatly improved, significant differences in accessibility between scales of regional, provincial and urban.The development of high speed rail network has a significant impact on daily communication area of central cities. Some Suggestions were put forward according to the problems of the development of Min Xin Axis Belt railway.

How to deal with the relationship between land intensive use and ecological environment, and realize the coordinated development of economic, social and ecological benefits of land use is an important issue in the construction of new urbanization. This paper used the panel data of 30 provinces, municipalities and autonomous regions in China from 2005 to 2016 to measure the land intensive utilization index and ecological efficiency through the global principal component analysis method and the superSBM model, in an attempt to reveal the coordinated development of land intensive use and ecological efficiency.The results showed that: (1) the level of land intensive use increased gradually, and the growth rate was shown as the east > middle > west > northeast region; (2) the ecological efficiency increased year by year, and the growth rate was shown as the east > middle > west > northeast region; (3)In 2016,23% of the provinces reached the coordinated development category, 14% of the provinces were close to the disorder category, and 63% were in the disorder decline category. Shanghai and Ningxia lagged behind in ecological efficiency, and other provinces lagged behind in intensive use of land. In addition, the coupling coordination degree had obvious spatial positive correlation, but the degree of agglomeration gradually weakened, and the spatial differentiation became more and more obvious.

The urban agglomeration is increasingly becoming the main areas of China’s new urbanization. The rapid urbanization in urban clusters has an unprecedented impact on land use transition (LUT). However, unclear spatial relationships between LUT and urbanization may limit the sustainable land use and the healthy development of urbanization. Based on the Landsat TM/ETM image interpretation data from 1995 to 2015, this paper measures LUT in the middle Yangtze River Urban Cluster (MYRUC) in three ways: land use dynamics degree, land use intensity, and land use diversity at 5 and 10 km grid scales. Our study examines the spatial and nonspatial relationships between land use transition and urbanization level using ordinary least squares model (OLS), spatial lag model (SLM), spatial error model (SEM), and spatial error model with lag independence (SEMLD). The results indicated that: (1) During 1995-2015, the land use in the MYRUC had undergone a profound transition. The net decrease of cultivated land was 6 153.80 km² and the net increase of construction land was 6 205.25 km². (2) The land use change speed, land use intensity and land use diversity in the prefectural level municipal districts, the surrounding grids and grids along the main traffic routes were significantly higher than other grids. (3) There was a significant positive spatial autocorrelation between urbanization and LUT at different grid scales. (4) The regression results showed that the SEMLD model could better explain the spatial relationship between LUT and urbanization than other models. Significant spatial dependence was found between LUT and urbanization in both 5 and 10 km grid scales. Our results suggest that policy makers should consider the significant spatial dependence between LUT and urbanization in the future land use management and urbanization development.

Ecological land plays essential roles in ensuring urban ecological security and promoting regional sustainable development. Hence, understanding the dynamic and driving forces of urban ecological land use change is of great significance to urban planning and ecological environmental protection. In this study, we proposed an integrated framework to modelling the dynamic and driving forces of urban ecological land use change. The land use matrix, landscape metrics, ecological service value and INVEST model were used to analyze the dynamics of ecological land use in terms of quantity, spatial pattern and ecosystem function respectively. Besides, the binary logistic regression model and gradient analysis approach were employed to modelling the driving forces of urban ecological land use change. Our experiments were conducted in Wuhan City, China. The results of our study demonstrated that between 1990 and 2014, the area of ecological land in Wuhan City lost 239.55  km2, and the quality of habitats also decreased by 24%. On the contrary, the fragmentation of ecological land plaques increased, which leads to the phenomenon of islanding. The results also illustrated that slope, the minimum distance to builtup area, the growth of built up area, GDP, and road density are the main drivers of urban ecological land use change in Wuhan. Consequently, with the continuous growth of Wuhan City, the risk of loss of ecological land, which located outside 3rd ring road of Wuhan, is increasing.

Land space is the carrier of human production, living activities and ecological civilization construction,however,how to promote the orderly, moderate and sustainable development and utilization of land space that is a scientific problem needs to be solved urgently.This paper based on the perspective of “Production Living Ecological”,which using entropy weight method and function evaluation analyzes the spatial characteristics of urban agglomerations in the upper reaches of the Yangtze river,and using the spatial function comparative advantage index, system clustering methods exploring its land space characteristics and optimization plan.The result are as follows:（1）The “ProductionLivingEcological”of the urban agglomerations is characterized by “less strong and weaker”in the upper reaches of the Yangtze River,the urban function measurement value in space shows not only decreasing trend from the core urban area to the peripheral area，but also lowvalue area overall distribution;（2）The ecological function measurement value is increasing from the core city to the peripheral area,and the contradiction between the construction of regional ecological security pattern and economic development is obvious;（3）Dividing the land space of the upper reaches of the Yangtze River into four dominant functional areas and proposed its the optimization plan.

In order to discuss the present situation and future trend of water resource carrying capacity in China,In this paper, the index system was constructed from the four aspects of pressure, pressure, coordination and management. The water resource carrying capacity of China from 2000 to 2015 was discussed through the comprehensive evaluation method based on entropy weight method. The characteristics of space time change were analyzed using m-k trend method, and the future trend was predicted by R/S analysis method.The results showed that: China’s deteriorating condition on the whole, the water resources carrying capacity in the north latitude 35°-40° are quite common, north and south on both sides of the area is better. The deterioration of water resources carrying capacity mainly occurred in northeast and southwest regions, while the improvement mainly occurred in southeast and northwest regions without significant changes. In the future, WRCC will continue to deteriorate in most areas of the country, mainly in the Inner Mongolia plateau, qinghai tibet plateau, yunnan guizhou plateau, north China plain, middle and lower Yangtze river plain and southeast coastal areas. Qinghai and hunan are likely to deteriorate; Other areas will show an improvement or likely improvement trend. The bearing potential of the southeast coastal area is large, the places of shanxi, shandong and Beijing are almost exhausted, and the advantages of the northeast and qinghai tibet plateau are gradually lost, so corresponding measures should be taken according to the bearing potential of water resources in different regions. Coordination system, management system, ecological environment in pressure system and pollutant discharge in pressure system are more controllable. The regulation of water resource carrying capacity can start from these aspects.

It is important to study water resources vulnerability in order to identify water resource problems and regulate water security. Water resources of the Yarlung Zangbo River basin are abundant, but its distribution is uneven, frequently flood and drought disasters and lower social economic development trigger spatial temporal differences of water resources vulnerability. Based on the monthly meteorological data from 1965 to 2014, the precipitation distribution and the dry-wet partition are analyzed. We analyzed the temporal spatial distribution of flood and drought disasters with the standardized precipitation index, and subsequently applied the entropy method to examine the temporalspatial differences of water resources vulnerability, based on the following three parameters of ‘flood and drought disasters and desertification’, ‘water supply and benefit’, and ‘regulatory capacity’. The results indicate that: 1) annual average precipitation is 458 mm in the basin and increases from northwest to southeast. Most of Rikaze in the upstream region, as well as Lasa and Shannan in midstream region are located in the semiarid climate zone, while Linzhi in the downstream belongs to the humid climate zone; 2) Spring droughts and midsummer floods usually occur within the basin, and the frequency of floods is lower than that of droughts. Lasa and Linzhi are more prone to experience severe droughts, while Shannan is more vulnerable to floods; 3) Water resources vulnerability in the basin and the four cities/prefectures shows a downward trend from 2005 to 2014, but the reduction in vulnerability is faster in Shannan and Linzhi than in Lasa and Rikaze; 4) The dominant factors influencing water resources vulnerability are floods, droughts, water use efficiency, management capacity, and GDP. In short, water resource vulnerability in this basin is dominated by floods and droughts, weak regulatory capacity and inefficient use of water.

Jiangsu Province is considered as an important grain production base in China. The change of cultivated land not only affects the sustainable development of region, but also relates to the food security of China. In this paper, 55 counties in Jiangsu Province were selected as study unit, and the mathematical statistics and GIS spatial analysis were conducted to analyze the spatialtemporal variations of cultivated land and grain production, and the sensitivity of grain production to cultivated land change during 2000-2015. The results indicated that the cultivated land in Jiangsu Province showed a decreasing trend, in which the relatively sparse areas were mainly distributed in Suzhou, Wuxi and Changzhou, while the agglomeration areas were mainly distributed in northern Jiangsu. The spatial pattern of grain production was consistent with the distribution of cultivated land, and the grain yield showed an increasing trend. In 2015, the grain yield in Jiangsu Province reached 3561×10⁴ tons, which was 1.15 times of that of 2000. In addition, the moving direction of gravity center of cultivated land and grain production are roughly same, and both of them move to northward and westward. Compared with 2000-2009, the sensitivity of grain production to cultivated land change in Jiangsu Province was gradually weakened during 2009-2015. With the development of agricultural technology, the dependence of grain production on cultivated land has gradually decreased. It is urgent to protect cultivated land, ensure food security in accordance with local conditions, and rationally allocate grain production for different sensitive areas.

The middle and lower reaches of the Yangtze River is the main area for rice and wheat producing in China. To clarify the environmental effects of agricultural production in this area can provide theoretical guidance for the realization of green agricultural development. In this study, we analyzed and evaluated the resource consumption and pollutant emission inventory of rice winter wheat rotation system in Nanjing, Jiangsu based on a method of life cycle assessment. Results indicated that the major environmental effects of the life cycle in rice season were eutrophication, water toxicity, environmental acidification and soil toxicity, with the environmental impact indices of 2.32, 0.76, 0.33 and 0.27, respectively. While in wheat season, eutrophication, water toxicity, soil toxicity and environmental acidification were the major environmental impacts, with the environmental impact indices of 2.50, 2.09, 0.32 and 0.24, respectively. The production and use of fertilizers, pesticides and diesel oil were the main factors for energy consumption and climate warming. The key to the potential environmental acidification and aquatic eutrophication were the excessive nitrogen fertilizers application by farmers. The input of pesticides was the main cause of potential water ecotoxicity and soil ecotoxicity, and the input of nitrogen fertilizers and pesticides both have a greater impact on human toxicity. As a result, the negative environmental impact can be effectively controlled by development of new energy sources and implement cleaner production in the industrial field, and optimizing field management (such as reducing the application of nitrogen fertilizer, developing multifunctional integrated agricultural machinery and promoting low toxicity and high efficiency pesticides) in the middle and lower reaches of the Yangtze River.

This study systematically analyzed the spatial distribution of the influencing factors of farmland soil organic carbon (SOC) in the Poyang Lake region by using the geographically weighted regression (GWR) model, and combined kriging interpolation algorithm to produce SOC map. The GWR Kriging (GWRK) and kriging (RK) methods were compared to identify the difference in predicting the SOC reserves. The results showed that: 1) The selected environmental influencing factor was relevant with SOC (P<0.01) according to Pearson correlation analysis; 2) There was a positive correlation between SOC and aspect, annual average temperature, and annual average precipitation, while a negative correlation was observed between SOC and gradient, vegetation coverage; 3) The values of SOC content ranged from 6.35 to 31.93 g kg-1 using the method of GWRK and approached to the measured values of sampling points. The values of SOC content ranged from 7.41 to 2.76 g·kg^-1 using the method of RK, and the overall spatial distribution characteristics were similar to the results of GWRK; however, the predicting results of RK were relatively smooth, which differed from the actual state of SOC reserves; 4) The goodness of fit of R2 in GWRK (0.50) was apparently higher than that in RK (0.20). The root mean square error of GWR is 4.58, which was less than the RK (5.35) of RMSE. Additionally, the predicting outcomes obtained using the GWRK reflected the positional information of sampling points, which could make the mapping elaborate.

In order to optimize the conservation tillage measures and improve the soil fertility, the study of soil organic carbon and nitrogen distribution characteristics and content changes of different growth stages in broad bean growth period under long term conservation tillage in southwest China was implemented. There were six treatments including traditional tillage, ridge tillage, traditional tillage with half amount of straw mulching, ridge tillage with half amount of straw mulching, traditional tillage with full amount of straw mulching, ridge tillage with full amount of straw mulching. The results show that soil total organic carbon(TOC), total nitrogen(TN), active organic carbon(AOC), particulate organic carbon(POC), the content of water soluble nitrogen(DN) distribution decreased in the order:0-10 cm layer > 10-20 cm layer under the different treatments. And the overall fluctuations are not large over time. During the period of broad bean growth, under the conditions of no straw mulching, soil TOC, TN, AOC and POC of ridge tillage are more than traditional tillage. However, with straw mulching, ridge tillage reduced soil TOC and POC, and with the increase of straw mulch, the contents of soil AOC and POC decreased. At the same time, whether flat or ridge, straw mulching was better than no straw mulching in terms of improving soil TOC, TN, AOC and POC. Correlation analysis showed that TOC was significantly related to TN, DN, AOC; TN was significantly related to POC, DN, AOC; POC was only correlated significantly with DOC; DOC was significantly positively correlated to DN; DN was very significantly positively correlated to AOC. The results showed that single ridge tillage or straw mulching could more effectively improve the status of soil carbon and nitrogen; and there was a certain coupling relationship between the different components of soil organic carbon and nitrogen.

To conduct a dynamic simulation analysis on the loss of agricultural land in the process of urban agglomeration development is conducive to summarize the trend and mechanism of the agricultural land loss accurately, and provide basis for the formulation of agricultural land conservation planning. Taking Changsha, Zhuzhou,Xiangtan urban agglomeration as an example, through the collection and processing of remote sensing images and the establishment of spatial database, the grid system, the 12 directions rose map and the 3D hill diagram, this paper conducted a dynamic simulation analysis on the processes of the expansion of urban agglomeration and the loss of agricultural land. Through the centrifugal model, the driving mechanism of the loss of agricultural land was concluded. Then we carried out a prediction on the loss of agricultural land in 2020 and 2025. The results show that: the expansion of urban builtup area is the main reason of the loss of agricultural land in Changsha, Zhuzhou, Xiangtan urban agglomeration. Along with the evolution of urban agglomeration spatial structure, the loss of agricultural land has experienced a process of Centers Leading Centers and Industrial Parks Co leading Continuous Loss. If not effectively controlled, until 2025, a continuously distributed mega metropolitan area with acreage of 1 500 km2 will form. Meanwhile, the agricultural land between existing urban centers and industrial parks will gradually disappear, resulting in irreparable environmental damage. The key of agricultural land protection includes two aspects: on the one hand, the spatial structure and development mode of urban agglomeration should be optimized by spatial planning, on the other hand, the occupation should be controlled strictly in terms of policies and regulations. The research of this paper could provide a methodological reference for the formulation of environmental protection planning for the urban agglomerations in China.

The adoption of green control technology for farmers plays an important positive role in reduction of pesticide, quality improvement of agricultural and protection of ecological environmental.. Based on 285 samples of citrus growers in Yichang and Danjiangkou of Hubei province and Ganzhou of Jiangxi province. Using the dual logic regression method analyzes the influence of market profit and government incentive and restraint policy on the willingness and behavior of farmers to adopt green control technology. Research shows that: （1) 36.14 % of sample farmers did not have true adoption behavior of green control technology with the intention of adopting green control technology. （2) The adoption behavior of green control technology of farmers is influenced by both of the market profit and the government's incentive and restraint policy. Under the condition of imperfect development of green market and insufficient incentive of market profit, government incentive and restraint policies can promote the adoption of green prevention and control technology in different degrees. That is, the government's incentive and restraint policies supplement the shortage of green agricultural products market and play an active role in guiding and regulating the prevention and control of green pests and diseases in farmers.

Climatesmart agriculture (CSA) is a novel agricultural approach developed by the United Nations. CSA aims to actively respond to climate variability and ensure sustainable crop production. Carbon reduction is an important goal in the development of CSA. Chinese agriculture is largely composed of smallholder farmers. Thus, it is important to develop CSA practices tailored to their specific characteristics. Using data from major rice production areas in the Hubei Province, this paper employs a directional distance function approach to measure low-carbon production efficiency and marginal carbon abatement costs for small scale farming. Additionally, we examine the impact of land transfer and agricultural socialization services on low carbon production efficiency and marginal carbon abatement costs. Our results show that (1) the efficiency of low carbon rice production for small-scale farmers is relatively low with the potential for average improvement of 56% in low carbon production efficiency. In addition, the average marginal carbon abatement cost is 30.64 RMB/kgCE. This indicates that low carbon rice production is costly for smallholder farmers in central China. (2) Although land circulation does not improve rice low carbon production efficiency, it reduces marginal carbon abatement costs. (3) Employment services and agricultural extension services have significant and positive impacts on rice low carbon production efficiency and marginal carbon abatement costs. Low-carbon production efficiency achieved through agricultural socialization services still faces the challenges of division of labor and transaction costs. Finally, based on our findings, we discuss policy recommendations in the development, promotion and implementation of CSA practices among smallholder farmers.

The farmers’ pro-environmental behavior can alleviate agricultural environmental pollution to a certain extent. In order to improve the agricultural environment and explore the reasons why farmers implement pro environmental behavior, this paper adds farmers’ perception of environmental pollution, environmental concern and social norms to extend the theory of norm-activation. On this basis, this paper uses field survey data from shaanxi, shanxi, gansu, anhui and jiangsu provinces to analyze the farmers’ pro-environmental behavior through the structural equation model and hierarchical regression model. The results show that the farmers’ pro-environmental personal norms, perception of environmental pollution and environmental concern have direct positive influences on their pro-environmental behavior, and the individual norms have the greatest influence on behavior. Awareness of consequence, ascription of responsibility, farmers’ perception of environmental pollution and environmental concern all have direct positive impacts on their proenvironmental personal norms, and the degree of their influence ranges from high to low is: awareness of consequence, ascription of responsibility, perception of environmental pollution and environmental concern; Farmers’ perception of environmental pollution and environmental concern have direct and indirect effects on their pro-environmental behaviors at the same time, while the awareness of consequence and ascription of responsibility only have indirect effects on their pro-environmental behavior. Social norms can positively regulate the influence of personal norms on farmers’ pro-environmental behavior.

Ecological farming plays an important role in improving the agricultural ecological environment, improving the effectiveness of farmland protection and ensuring the quality and safety of crops. Based on the micro-survey data of 1488 households in 47 counties (districts) of 11 cities in Jiangxi Province, under the guidance of the theory of planned behavior, the Logistic regression model was used to conduct empirical research on the influencing factors of farmers' willingness to adopt ecological farming. The results of the study showed that (1) 89.85% of the sample farmers expressed their willingness to adopt ecological farming, maintained the expected income and promotion expectations of ecological farming at a high level. (2) Behavioral attitude, subjective norms and perceptual behavior control have significant influence on farmers' willingness to adopt ecological farming. Among them, ecological farming promotion prospects, production exchange, neighborhood effect, policy subsidy and technical training variables are the key factors affecting farmers' willingness to adopt. . (3) Under different qualifications, the factors affecting farmers' willingness to adopt ecological farming are different. Among them, income expectation, information dissemination intensity and technical training have stronger influence on the low-promotion prospects of farmers' ecological farming adoption intention; the lower the risk expectation, the lack of communication Farmers' willingness to adopt is more influential; farmers with small neighborhood effects are mainly affected by information dissemination and technical training; farmers who need policy subsidies have more frequent production exchanges, stronger neighborhood effect, and stronger adoption intentions; Farmers, the factors affecting their willingness to adopt are mainly income expectations and information dissemination. The government should formulate targeted measures in strengthening the promotion and promotion of ecological farming, building a production exchange platform for farmers, and improving ecological farming subsidies and incentive policies.

This study examines suspended sediment concentrations (SSC) and compositions at Xuliujing in the Yangtze Estuary based on field data from 2003 to 2017 (15 years). Data analysis suggests that the average SSC of surface (2003-2017), middle-layer, and bottom (2010-2017) at Xuliujing was 0.07, 0.07, and 0.13 g/L, respectively. Overtime the SSCs exhibit a statistically significant decrease trend over the 15 years. The decline during the wet season is more severe than the dry season. Compared with the average SSC in 2003-2005, the mean SSCs have decreased by 57% and 20% in the wet and dry seasons, respectively, in 2015-2017. The surface SSCs exhibit a change points in 2008, with a mean decrease by 56% and 44% in the wet and dry seasons, respectively. Furthermore, the sediment composition exhibits irregular variations that maybe attributed to human activities, but insignificant directional changes over the study period. The D50 is 7.3, 9.4, and 11.0 μm at surface (2004-2017), middle-layer and bottom (2009-2017), respectively. 

In order to research the law of blue algae bloom in Lake Chaohu, this paper used the Landsat satellite image as a data source and extracted algal blooms by AFAI index to analyze the temporal and spatial variation of the blue algae bloom in Lake Chaohu and the main driving force of blue algal bloom outbreaks in Lake Chaohu was discussed. The results showed that the frequency and duration of outbreaks of blue algal blooms in Lake Chaohu from 1983 to 2017 increased; the earliest time of the outbreaks in the calendar years gradually advanced; the area covered by algal blooms showed an overall increase trend. Lake Chaohu algae is mainly distributed in the northwest entrance to the lake, and the northwest is the core area of blue algal blooms in Lake Chaohu. From the analysis of its driving forces, the atmospheric pressure, air temperature and wind speed were important factors affecting the outbreak of Lake Chaohu. In addition, the Lake Chaohu population growth, rapid GDP growth, increased fertilization and increased domestic sewage discharge were important human factors that caused the blue algae bloom phenomenon in Lake Chaohu to become increasingly serious.

Based on the data of river network of the Southern Jing river in different period from 1955 to 2016, the changing process of river network connectivity was studied from three aspects: strength of river system and hydraulic connectivity, river network connectivity and level of river network connection. Results show that comparing with 1955, in 2016, (1) the hydrological connectivity demonstrated a decrease trend but with moderate changes; (2) the circuitry of river network connectivity α, node-connection rate β, and river network connectivity γ were all decreased by 45.45%, 10.80% and 8.46%, respectively, of which the node-connection rate β demonstrated the most significant trend; (3) based on two methods evaluating the river network connectivity (e.g. ① E: river network connectivity with respect to the natural and social functions of river network, and ② F: river network connectivity with respect to the hydrological process and flow resistance) the river network connectivity of the three outlets of Southern Jing river has been collectively evaluated. Both of the results derived from the two individual method show that river network connectivity in the study area presented a downtrend that decreased from 0.2367 and 0.3434 in 1955 to 0.1588 and 0.2517 in 2016, respectively. The results of this article could be theoretical references for both river network or lake connectivity recovery projects and riverine ecological system restoration.

Based on the daily streamflow data of Chenglingji station from 1960 to 2016, two eco-flow metrics, ecosurplus and ecodeficit, were used to evaluate the changes in streamflow and their related ecological effects at the outlet of Dongting Lake. Both annual and seasonal eco-flow metrics were analyzed and the ecosystem influences were also discussed. The results indicated that the average annual ecosurplus and ecodeficit fell in the range of 0-0.39 and 0-0.47, respectively, and the annual ecodeficit had a more frequent fluctuation than the annual ecosurplus. Changes of seasonal eco-flow metrics differed greatly. Ecosurplus had frequent fluctuations in spring and winter, while had no significant fluctuations in summer and autumn. Seasonal ecodeficit showed an increased trend in all seasons except for winter, and were higher than the values of seasonal ecosurplus. The total seasonal ecochange increased during the whole period, and became more discrete during the post-impact period, which indicated a severely disturbance on the ecosystem. Climate change and human activities are two main factors of the eco-flow alteration at the outlet of Dongting Lake. Furthermore, precipitation had greater impact on ecodeficit. Human activities may lead to a large alteration of seasonal eco-flow metrics, through reducing high flow and increasing low flow. According to the four basic principles of flow regimes and ecosystems, Streamflow of Dongting Lake outlet had a close relationship with the ecosystems, and streamflow alteration had negative impacts on the ecosystems.

In order to protect the water environment of Xiangjiang River scientifically and effectively, and quantitative identify the main driving factors of water quality. In this paper, the Mann Kendall was used to analyze the water environment evolution trend of Xiangjiang river trunk stream, the stepwise regression analysis methods were used to determines the main driving factors of water quality indexes in different regions, which is based on water quality monitoring data from 1990 to 2016 and socioeconomic development indicators of cities along the coast. The results show that COD_Mn, Cd and As was downtrend, BOD₅ shows an downtrend in the upper reaches, the pollution of NH₃-N in the upper and middle reaches shows an upward trend,TP in Hengyang shows an upward trend, in the middle reaches of Hengyang and Zhuzhou regions, heavy metal Cr⁶⁺ shows an increasing trend, BOD₅ in the middle and lower reaches shows an increasing trend; It is concluded that industrial pollution is the main driving factor of heavy metals As, Cr⁶⁺and Cd in Xiangjiang River trunk stream. NH₃-N in Yong Heng Zhu Tan, BOD₅, COD_Mn, TP in Hengyang and BOD₅ in Heng Zhu Tan are mainly affected by agricultural pollution; it is found that the industrial structure adjustment has a significant impact on the water environment, it is suggested to strengthen the transformation and upgrading in the process of industrial structure adjustment in the basin.

The stratified water intake is an important engineering measure to improve the adverse effects of low-temperature water discharged from reservoirs in domestic area. In order to clarify the attenuation effect of stoplog gate in cascade reservoir utilized river section, the influence of the upstream reservoirs on the downstream under the condition of cascade-combined operation in 4 cascade reservoirs of Jinsha River were investigated by using the laterally averaged 2D reservoir water temperature model. The results demonstrated that low temperature water discharging from Wudongde Reservoir did not be effectively prevent by stoplog gate, which was on the contrary of Baihetan Reservoir. The impact that the stratification water intake at Baihetan pose to the low temperature water discharged from Xiluodu and Xiangjiaba, was slightly weakened, and the discharging temperature from Xiluodu to Xiangjiaba in April and May can be increased by 0.8℃ and 1.0℃ respectively. Moreover, the stoplog gate in Wudongde Reservoir played little effect on improving the discharge temperature of Xiluodu and Xiangjiaba. Under cascade development, The stratified water intake measures should be implemented as far as possible on reservoirs with strong regulation capacity.