This report is concerned primarily with multiple discharges and the effects on dilution of neighboring plumes interfering with one another. In an effort to obtain quantitative information concerning the dilution characteristics of merging: thermal discharges and in order to isolate these effects from others such as surface and bottom interactions, deep submerged discharges were experimentally and analytically investigated. The results of this investigation are presented in two parts. The first part is concerned with the experimental program. The second part details a recently advanced multiple port analysis and presents the results of its application to the discharge conditions considered in the experiment