Design And Research On The Water Quality Analysis And Evaluation System

The paper researches the analysis-and-evaluation system of water quality, based on the theory and relevant knowledge of software engineering. Three main points are stated as follows: the general design, detailed design and database design.In the designing section, we use B/S ("browser/application server/database server architecture") architecture, and B/S structure. Its characteristic is that the client front-end interface uses our common browsers; and client back-end uses application server and database server. The client terminal gets access to servers and the back-end data connected to the servers, issuing data request. Then the application server or the Web server will give data requests to the back-end database server and do calculations. At last, the calculated results are returned to the browser.The detailed design part offers a specific design method of water quality analysis and evaluation system. Water quality analysis and evaluation system uses network technology, database technology, WEB technology and GIS technology as the framework,"National Surface Water Environmental Quality Evaluation Standards"as the core, the water environmental data from National Hydrological and Water Quality Station's collection and laboratory analysis as a basic source of data. It has achieved an organic integration of various subsystems, by joining them together. The system, together with the other systems used by the water environment, constructs a national water environment monitoring and managing system.The various subsystems including:1) Network system. The system uses Hydrographic Office data applications as the core, supporting telephone or ISDN dial-in services and covers nationwide water environment monitoring stations'network application systems, and water environmental database. In accordance with watershed relationship, it is able to provide the necessary environmental assessment for water environment evaluation. The system is able to record, query, and retrieve data by means of logical combination and spatial relationship combination.2) GIS application system. It is based on electronic map, with which you can easily query and manage. The GIS application system can achieve managing water environment parameters of reservoirs, rivers, lakes and the different water layers (surface, middle, and bottom) of reservoirs. It can also make automatic classification and show different levels of water environment with different colors.3) According to the content analysis of water environmental assessment, the system should be able to support large data's storage and query. Moreover, it can collect and share data through the network. The whole system is based on the latest technology. It can work in a timely manner for the Flood Control and Drought services and in time for the water environment monitoring service. The system has the ability of working for long and in a stable way, reaching a higher standard in reliability, practicality, easy using, advancement, opening, and stableness than the normal information building.Database design mainly includes the external design, structure design, database conventions and specific guidance of a database.In the end, we have established a water quality analysis and evaluation system, having solved the following problems:1) We have established a set of water quality analysis and evaluation model suitable for different regions. Allowing for China's vast territory, the water quality data collected from different reaches or regions differ greatly from one another. Through the establishment of suitable water quality analysis and evaluation model suitable for different places, we can offer provision of modern scientific and technological support for scientific analysis and evaluation of water quality condition.2) In accordance with the time sequence, the system tracks water quality evolution model dynamically. Changes in water quality will directly affect people's lives and safety and environmental condition. What's more, the research design focuses on a dynamic tracking of the continuously changing condition of water quality, which is in a chronological order and of a particular river basin or a certain water quality monitoring site, so that the decision-making departments can grasp the trend of changes in water quality in a timely manner and make scientific decisions.3) The system has established a subsystem of water quality forecasting. This study is designed to use data mining techniques, calibration model and mathematical- statistical techniques. Through continuous model calibration and parameter adjustment, the acquisition of a set of applicable and practical model can be achieved, and as such, the initial establishment of a water quality forecast system can come true. Then we are able to adopt scientific and corresponding measures and effectively prevent and control the water pollution with the scientific basis provided by the system.The water quality analysis and evaluation systems which are designed in this paper have such major characteristics of innovations as follows:1) Having developed a set of WEBGIS-platform-based application system, realizing the close integration between WEBGIS and water environment assessment.2) Having achieved fuzzy query of total factors of the corresponding information in the information querying process.3) On the basis of water quality database, having established a hierarchical relationship to meet users'needs of deep mining of water quality data.The water quality analysis and evaluation systems which are studied and designed in this paper have greatly improved the efficiency and quality of the water quality monitoring and analysis and evaluation, however, with advances in technology and in-depth study of water resources planning, new needs are continuously produced, and will bring more demands to the development of the system. Therefore, allowing for the future, we should adapt to the growing new requirements proposed by water quality analysis and evaluation. Then we can correspondingly transform, improve, and upgrade the system. The technical issues which we need to give further research and improvement in the future include:1) Improvement of data's importing process in bulk.2) Improvement of the curve of Songhua River pollution.3) In-depth applications of WEBGIS technology, such as statistical analysis, the shortest path analysis and so on.