Three related investigations are to be conducted in the area of environmental fluid mechanics, in particular density stratified turbulent flow. The approach is essentially experimental. The three topics are: mixing between turbulent layers of different properties separated by a laminar region, the horizontal outflow generated near the ground by heavy descending air masses, and mixing and internal wave generation in a variable properties stably stratified turbulent shear flow. The research is relevant to oceanic mixing, pollutant transport in the atmosphere, and wind shear due to microbursts.