The complexity and enormity of the environmental decision making requires the use of computer-based support. Indeed, many partial solutions already exist in the form of many and diverse numerical models and their computerized implementations. The problem is that, because of the diversity and lack of a comprehensive implementational solution, a number of difficulties have arisen in the use of these modeling systems, and in communication of the information amongst them. US EPA and MCNC of North Carolina have decided that a solution the problem is an integrated platform for conduct of environmental studies, that is, data aquistion and preparation, data analysis, numerical modeling, problem formulation, problem solution, and decision making. The project is in its third year and the second prototype of the system, called Environmental Decision Support System (EDSS) is available for alpha-level testing. In this presentation we will describe the system framework and the facilities for integration of numerical components in a plug-and-play fashion. Integration is provided using the concept of "software bus", a specialized message brokering system, and a collection of object libraries that interface the elements. If facilities permit, we can demonstrate the system.