Study On Watershed Water Pollution Control Decision Support System Based On Scenario Analysis

River watershed pollution control Decision Support System (DSS) could offer integrated and effective support for watershed point source pollution control and management. The system integrated lots of informational technologies such as database & Data Base Management System (DBMS), model base & Model Base Management System (MBMS), Geographical Information System (GIS), Expert System (ES), developed a comprehensive application platform. It have been researched and applied extensively.The common water pollution decision support systems were based on GIS or data management. System simulation function and decision-making function had been weakening. This research raised Scenario Analysis as the mainline, used water environment modeling under hypothetical situations as means, studied the point source pollution control decision-making method. It effectively avoided the shortcomings that the traditional watershed decision only focuses on the issue of data management. In this research, an information system was developed, which supported scientific and effective propose for decision-making at the watershed scale.In models and MBMS research, a series of models was developed, including gray prediction model for urban domestic sewage discharge, multiple regression model for urban industrial wastewater emission, one-dimensional water quality model, fuzzy evaluation model for multi-section river. These primal models were applied to idiographic areas to give different parameters, and then re-generated different models. Combining the database and documents base, a MBMS was developed to manage models, increasing the reusability and expandability of models.Supported by the integrated models, effects of different control measures were studied on the water quality of the river. Four scenarios were assumed and analyzed. Results of the base case scenario showed that the pollution of CODMn featured significant role in the Songhua River upstream and meanwhile NH3-N pollution played a dominant role in the middle and lower reaches. Scenario 1, 2 and 3 investigated effects of different pollution control measures on the water quality of the river. Results showed that domestic sewage discharge was more conducive to integrated watershed pollution control target. The conclusion showed that the strengthening of the Songhua River Basin domestic sewage drainage control was more valid and more necessary to improve Songhua River water quality.River watershed pollution control Decision Support System based on Scenario analysis method could offer qualitative and quantitative description of water quality under a certain control mode, so as to provide reliable proposal for the control decision making for the Songhua River watershed.