Understanding the spatiotemporal patterns of water quality is crucial because it provides essential information for water pollution control. The spatiotemporal variations in water quality for the Nanxi River in the Taihu watershed of China were evaluated by a water quality index (WQI) and multivariate statistical techniques; additionally, the potential sources of contamination were identified. The data set included 22 water quality parameters collected during the monitoring period from 2015 to 2020 for 14 monitoring stations. WQI assessment revealed that approximately 85% of monitoring stations were classified as “medium-low” water quality, and most showed continuous improvement in water quality. Cluster analysis divided the 14 monitoring stations into three clusters (low contamination, medium contamination and high contamination). Discriminant analysis identified pH, petroleum, volatile phenol, chemical oxygen demand, total phosphorus, F, S, fecal coliform, SO4, Cl, NO3-N, total hardness, NO2-N and NH3 as important parameters affecting spatial variations. Factor analysis identified four potential contamination source types: nutrient, organics, feces and oil. This study demonstrated the usefulness of multivariate statistical techniques in assessing large data sets, identifying contamination source types, and better understanding spatiotemporal variations in water quality to restore and protect water resources.

Taking Liyang City of Jiangsu Province as the research object, a water pollution accident diffusion simulation and analysis system, taking WebGIS as the core, was established by taking finite difference method to do the system dynamics water quality model solution. This paper introduces the construction process of the model, the integration of the model with GIS, the interactive application of the system and users and the visual dynamic expression of water pollution accidents. By combining the statistical analysis of the spatial and environmental database in the system, the scientific simulation of the temporal and spatial relationship of the development of water pollution accidents on the client side is realized and providing precise decision support for early warning and control of water pollution diffusion.

A surface water quality analysis and pollutant diffusion simulation system was studied and developed using WebGIS. This paper introduces the structural design, technology development and main functions of the system. Using Liyang City of Jiangsu Province as an example, an environmental water monitoring database was established. Based on the database, a comprehensive analysis and evaluation of water quality in Liyang City were determined and provided decision support for pollution management. In addition, two authoritative water pollution diffusion analysis models (including a one-dimensional model and a two-dimensional model) were integrated, and a dynamic simulation of water pollution accidents was constructed with the support of GIS technology.