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Dynamic monitoring of water environment is the basis of maintaining urban security and promoting urban sustainable development. To effectively solve the problems caused by the large-scale flooding of floating aquatic invasive plants, such as water environment destruction, clogging river, water quality pollution, water ecological balance destruction, etc., a satellite and ground multi-sensor collaborative sensing method for floating plants is proposed in this paper. For the monitoring of floating plants in macro watershed, the vegetation index and chlorophyll concentration were used to extract floating plants, analyzing, and calculating the distribution and coverage area of floating plants based on 4-band high-resolution satellite images. For the monitoring of floating plants in small watershed, combined with visible light video, multispectral images, and LiDAR data, optimized spectral feature variable processing, semantic segmentation network, and symmetric function neural network are utilized to obtain real-time information on the invasion location, distribution pattern, and coverage area of floating plants. In this paper, the upstream basin of the Huangpu River in Shanghai in 2023 was selected as the experimental area. The distribution of floating plants in different watercourse and different periods was successfully obtained by this method, and the coverage area was accurately calculated with an identification rate of more than 90%, which provided technical support for cross-regional management and efficient cleaning of floating plants. [ABSTRACT FROM AUTHOR]

Waterlogging induced by rain in urban areas has a potential risk impact on property and safety. This paper focuses on the impact of rain on waterlogging and evaluates the waterlogging risk in the central city of Shanghai. A simplified waterlogging depth model is developed in different areas with different drainage capacity and rainfall in consumption of simplifying the effect of complex terrain characteristics and hydrological situation. Based on urban waterlogging depth and its classification collection, a Rain-induced Urban Waterlogging Risk Model (RUWRM) is further established to evaluate waterlogging risk in the central city. The results show that waterlogging depth is closely linked with rainfall and drainage, with a linear relationship between them. More rainfall leads to higher waterlogging risk, especially in the central city with imperfect drainage facilities. Rain-induced urban waterlogging risk model can rapidly gives the waterlogging rank caused by rainfall with a clear classification collection. The results of waterlogging risk prediction indicate that it is confident to get the urban waterlogging risk rank well and truly in advance with more accurate rainfall prediction. This general study is a contribution that allows the public, policy makers and relevant departments of urban operation to assess the appropriate management to reduce traffic intensity and personal safety or strategy to lead to less waterlogging risk. [ABSTRACT FROM AUTHOR]

Geographical accessibility is closely related to people's daily lives and has been extensively studied. One understudied area is the accessibility of churches that provide for the spiritual needs of a large number of people. Based on census data, this paper explores the geographical accessibility of Protestant churches in the inner city of Shanghai, the largest metropolis in China. Two spatial research methods, the two-step floating catchment area and the raster catchment overlay methods, are used to examine church accessibility. To determine the church catchment, this study established a 40-min public transportation radius. A WebGIS API is utilized to obtain the real transit time between the designated locations. The results show that 97% of the people living in inner cities, or approximately 10.39 million people, can travel to at least one church within 40 min via public transportation. The downtown area enjoys very good accessibility, and there are many places of worship for adherents to choose from there. Very poor accessibility (beyond 40 min) was found in the peripheral area, located mainly near the mouth of the Huangpu River and the southeast corner of the Outer Ring of Shanghai. This study could be of great significance for urban planners in considering religious services in traffic planning and for the site selection of churches. [ABSTRACT FROM AUTHOR]

With population ageing being a notable demographic phenomenon, aging in place is an efficient model to accommodate the mounting aging needs. Based on the community scale, this study takes the 15-min community-life circle as the basic research unit to investigate the imbalanced distribution of pension resources and its influencing factors in downtown Shanghai. We obtained six types of elderly care facilities data from the Shanghai elderly care service platform and utilized the Gaussian 2-step Floating Catchment Area method to calculate the accessibility of 6-type elderly care facilities. Then, we used the Entropy Weight Method to calculate the comprehensive accessibility of elderly care facilities. The Getis–Ord Gi* method was adopted to analyze the overall distribution, identifying the well-developed and the under-developed areas. To explore the influencing factors of the distribution, this paper obtained multi-source data to construct a total of 17 indicators and established a Random Forest model to identify the feature importance. With the selected eight factors, the Geographically Weighted Regression (GWR) model was applied to study the spatial heterogeneity of influencing factors, and the model showed a good performance with the AdjR2 being 0.8364. The findings of this research reveal the following: (1) The distribution of six types of elderly care facilities is extremely uneven, with obvious spatial aggregation characteristics. Amongst the seven administrative regions, Huangpu District has the best accessibility to pension resources, while the resources in the other six regions are highly inadequate. (2) Essential influencing factors of the comprehensive accessibility of community-based elderly care facilities are accessibility of nursing institutions (positive), hotel density (positive), catering density (negative), education density (positive) and medical density (negative), while "rents", "plot ratio" and "building density" have little impact on comprehensive accessibility. (3) The results of GWR revealed that the eight indicators are heterogeneous in space, all of which have bidirectional effects on comprehensive accessibility. By investigating the spatial distribution patterns and influencing factors of pension resources in Shanghai, this research could further contribute to establishing a sound community-based elderly care service system that improves older adults' quality of life and promotes social fairness and justice. [ABSTRACT FROM AUTHOR]

The River Chief System (RCS), an innovative top-down and bottom-up water resource management system in China, is implemented to manage increasingly complex water environment issues. However, there has been a time lag in policy implementation. To accurately and scientifically assess the effect of RCS, a dynamic multiple-attribute decision-making method considering the time factor (DMADM) has been proposed. We have constructed the model consisting of 17 indicators from four aspects and determined the index weights and time weights by using the gray relation analysis method, the maximum entropy principle, and the subjective empowerment method. Finally, we applied the model to evaluate the water environment governance effect in the Taihu Basin from 2008 to 2020. The results have been ranked by possibility degree matrix, showing that: (1) The water environment in Taihu Basin maintains a steady improvement trend until 2014, except in Jiangsu Province;(2) The ranking result of the final comprehensive evaluation value is Shanghai ([0.334, 0.376]) ≻ Zhejiang ([0.316, 0.353]) ≻ Jiangsu ([0.305, 0.336]). Shanghai is far ahead with systematic pollution control measures, while Jiangsu lags due to the large fluctuation of pollutants (COD, NH3-N) in the wastewater. The study finds that the water environment management in Taihu Basin did improve over the past years, but failed to achieve the RCS governance goals at each stage. Enhancing coordination and cooperation and improving supervision mechanism for precise governance can better consolidate the results of RCS governance. [ABSTRACT FROM AUTHOR]

Water ecology has always been key to environmental protection, and the combination of human activities and natural factors has caused eutrophication in the Yangtze estuary and adjacent waters. Among them, dissolved oxygen (DO) concentration is the key indicator to judge the quality of water. Firstly, using principal component analysis (PCA) to determine the number of parameters affecting dissolved oxygen concentration, the least squares support vector machine (LSSVM) prediction model with improved particle swarm optimization (IPSO) is proposed to be applied to the dissolved oxygen prediction in Shanghai's Yangtze River basin through the data-driven modeling approach and the regression prediction capability of the neural network. Eight parameters of water temperature (WT), pH, potassium permanganate (KMnO4), ammonia nitrogen (NH4+-N), total phosphorus (TP), total nitrogen (TN), conductivity (Cond), and nephelometric turbidity unit (NTU) are selected as model inputs in the published public data, and the output is the dissolved oxygen concentration. The optimal combination of model parameters is found according to the IPSO algorithm, which effectively overcomes the parameter selection problem of regular support vector machines (SVM). The mean absolute error (MAE), root mean square error (RMSE), mean absolute percentage error (MAPE), and correlation coefficients of the evaluation indexes of this model (R2) are 0.1702, 0.2221, 0.0267, and 0.9751, respectively. Compared with other similar data driven models, this model has improved model accuracy and stability in predicting DO concentrations in the estuary, and thus it provides technical support for assessing and monitoring offshore water quality. [ABSTRACT FROM AUTHOR]

• Improve the traditional emergy ecological footprint by integrating it with DEA-SBM. • Construct an ecological security assessment framework. • Develop the environmental technology investment efficiency index. • Fill the gap on quantitative research of ecological security for megacities. Environmental problems caused by intensive economic development and rapid urbanization have seriously constrained the sustainable development of social economy. Ecological security assessments have become an effective tool for measuring the unsustainability bottom line. Although Shanghai, Nanjing, Suzhou, Hangzhou, Wuhan, Hefei, Chongqing, and Chengdu are developed megacities in the Yangtze River basin of China, they are located in a fragile ecological environment. The megacities of the Yangtze River basin must achieve sustainable development based on an appropriate assessment of ecological security so that suitable suggestions can be proposed. To quantitatively measure and analyze the ecological security levels in these eight megacities in 2007–2016, this study applied the improved emergy ecological footprint model which optimizes the traditional emergy ecological carrying capacity by adding the new account of the socioeconomic emergy ecological carrying capacity. To improve accuracy, the environmental technology investment efficiency in the socioeconomic account was introduced using the slack based measure model of undesirable output. Then, this study constructed a framework of ecological security assessment. The results showed that from 2007 to 2016, the renewable resources carrying capacity varied greatly among these eight megacities which had an absolute effect on the contribution of emergy ecological carrying capacity. Environmental technology investment efficiency failed to increase. However, in the short term, it effectively increased the socioeconomic carrying capacity for megacities with poor renewable resources. The emergy ecological footprint followed a growth trend in Shanghai, Nanjing, Hangzhou, Hefei, and Chongqing, and a decreasing trend in Suzhou, Wuhan, and Chengdu. Across the study period, ecological deficits were identified in Shanghai, Suzhou, Nanjing, Wuhan, and Hefei. Hangzhou, Chengdu, and Chongqing had ecological surplus because of their superior renewable resources and their ecological security. Nanjing and Wuhan changed their status from sub-secure to secure. Except for Shanghai, the ecological footprint diversity indexes of all other megacities followed a growth trend, indicating that their consumption structure improved. Finally, this paper provides policy recommendations to help decision-makers formulate ecological security and sustainable development strategies. The results of this study provide a scientific reference for other megacities to mitigate ecological pressures by considering their local situations. [ABSTRACT FROM AUTHOR]

Taihu Lake Basin is highly developed but suffers from perennial water shortages due to pollution. Most studies have been limited to examining the water quality in specific areas, but few have investigated the entire basin. This study was based on official water quality data obtained from 565 sites in the monitoring network, thereby covering the entire basin. The water quality spatiotemporal variations were explored by statistical analysis, and the precise spatial distribution of the main pollutants was analyzed by heat maps. Only 29.09% of the water quality assessment results showed "drinkable," whereas 28.63% showed "moderate" and "severe" pollution. The "severe" proportion had a significant declining trend (R2 = 0.933) and was affected by the variations of nitrogen that was related to rainfall and anthropogenic activities. The water quality spatial variation was most likely related to anthropogenic influence and land use. The water quality in the developed and densely populated urban areas was poor, especially in downtown Shanghai. NH3-N, TN, TP, BOD5, COD, CODMn, and DO were the main pollutants that affected the water quality. NH3-N and TN were major reduction targets. NH3-N was the main pollutant that deteriorated the water quality in most densely populated urban areas. Many lakes and reservoirs were highly polluted with TN. Controlling domestic sewage may be effective to improve the water quality. This study makes up for the limited research on the water quality spatiotemporal variations in the entire Taihu Lake Basin and provides beneficial information and suggestions for decision-making regarding the water management. [ABSTRACT FROM AUTHOR]

Coupled human and natural system research is an urgent issue in the Anthropocene. However, this has not yet been conducted from the perspective of multiplex networks, which are a powerful tool to elucidate the interactions in human-natural systems. This paper establishes a framework of human-water multiplex networks (HWMNs) to explain the combined effects of human-water interactions in the Yangtze River basin. The spatial linkages and the status of each province in the Yangtze River basin can be characterized through the index of network flow and topology. Research demonstrated that the highest import flow of the virtual water environment capacity flow in the Yangtze River Basin is to Jiangsu Province, at 16.2 thousand t. The highest export flow in the Yangtze River Basin is from Shanghai city, at 33.2 thousand t. The control power of Shanghai city over Sichuan Province accounts for 56.59% of the water resources, which is the highest value and can be recognized as one type of telecoupling of water resources. The provinces in the delta of the Yangtze River basin, including Shanghai city, Jiangsu Province and Zhejiang Province, benefit the most from economic trade. The community structure of the virtual water environment capacity flow is highly consistent with the geographical distribution of the Yangtze River basin. Comprehensive research methods combined with network flow analysis and network topology analysis provide more general results. The microenvironmental effect of indirect pollutant discharge is uncovered through HWMNs. This research can provide a more connected view of integrated water management. Image 1 • A framework of HWMN is established to reveal the combined environmental effects. • The key provinces are revealed through the network flow analysis and topology analysis. • The provinces in the Yangtze river delta obtains most of the water environment benefits. • The environmental effect of the indirect pollutant discharge through HWMN is revealed. [ABSTRACT FROM AUTHOR]