ABSTRACT
The increased awareness of environmental/ecological issues which has surfaced over the last two or three decades is reflected in civil engineering research and development. Many major firms of consulting engineers now find that work in this field has grown considerably. In this book some environmental aspects of civil engineering hydraulics have already been encountered (e.g. hydrology, floods, sediment transport). This chapter is intended to introduce some other aspects, in particular pollutant dispersion and some problems involving density differences in fluids - the number of studies in these and cognate areas is large. A great deal of effort is being expended in improving numerical modelling techniques and rapid developments in the field of numerical models and computer packages have been a feature of recent times. These models may, for example, combine representations of the flow field and of the mechanisms which disperse pollutants, and may be used to predict the path and dilution rates of pollutants injected into a hydraulic system such as a river, lake or sea. Studies involving the modelling of these types of problem are often placed under the general heading of 'Water Quality Modelling'. This chapter will concentrate on the hydraulic aspects of three types of problem, namely dispersion, buoyant jets and intrusion due to density currents.
