A submerged multiport diffuser is a linear structure consisting of many closely spaced ports, or nozzles, through which wastewater effluent is discharged at high velocity into the receiving water body. In many respects, multiport diffusers offer an attractive engineering solution to the problem of managing wastewater discharges in an environmentally sound way. They offer a high degree of initial dilution that can be controlled through choice of the diffuser geometry. Furthermore, the overall features of the mixed diffuser effluent plume can be optimally adapted to the assimilative characteristics of the water body through appropriate selection of diffuser siting, alignment, and the dynamic flux parameters. The present discharge classification scheme has been implemented as the microcomputer-based expert system program CORMIX2 (Cornell Mixing Zone Expert System, subsystem 2 for submerged multiport-diffuser discharges). The user of CORMIX2 is informed at important decision points on the hydrodynamic aspects of the flow simulation under consideration.