Environmental modelling in river basin management

Details are given of the growing world-wide public concern relating to hydroenvironmental issues for river basin management and examples are cited of some of the flooding and water quality and contaminant problems now being considered by river engineers and managers on a regular basis. The limitations and restrictions of both physical and computer hydraulic models are discussed and concern expressed with regard to the increasing use of computer models being made by non-specialist engineers and scientists - often with little understanding of the complex physical and computational processes involved - to assist in the planning and management of river basin systems. General details are given of the computational or numerical models used for flow, water quality, sediment transport and toxic contaminant concentration predictions in river and estuarine basins and three example studies are described. In these three studies various hydroenvironmental aspects are considered, including: the impact of dynamic decay rates on receiving water quality, refined sediment transport modelling for contaminant transport, flooding and water quality interactions and the use of decision support tools for river basin planning.