Presently there are two widely used methods of discharging thermal effluent. The first uses a large single surface jet; this method is used primarily in large lakes and reservoirs where surface stratification is desired. The second, used for river and estuary sited plants, consists of a large number of closely spaced jets located on the river bottom. To gain a better understanding of the second case, a two-dimensional, submerged slot jet was studied. Mean velocity profiles and turbulent intensities were obtained for unheated jets and mean temperature profiles were obtained for heated jets. Two angles of jet injection were used with a wide range of velocity ratios. An integral method was developed to predict the trajectory, spreading, velocity decay and temperature decay of a two-dimensional heated jet.