Solute (pollutant) and sediment transports directly relate to controlling water quality in water environment (e.g. river, estuary and reservoir). An understanding of turbulent diffusion is the key for improving water quality in rivers and estuaries. Many studies on turbulent diffusion have been carried out in open channels, compound channels and estuaries for different flow conditions in the past. This paper reviews the past research mainly carried out by the author and includes flow structures, solute concentration distributions, mixing parameters in simple open channel, compound channel, rivers and estuaries. Sediment transport rates and bedforms in meandering channel for flooding are also included.