Historically, most hydrologic models have assumed that all ¿losses¿ (i.e. rainfall which does not result in direct runoff) have occurred in the hydrologic component of the modelling system. As a result, no losses have been assumed to occur during propagation of flows along channels in the hydraulic component of the modelling system.

The focus of this project, therefore, is to collate information and to develop necessary information about ¿losses¿ that occur as a result of flow in channel. It should be noted that these ¿channel losses¿ are very significant in arid zones where flow in a channel may seep out during its downstream progress. Consideration of these losses has been an issue for some time in the literature, see Jin and Fread (1996) for example, with the result being that the technology is available to differentiate between catchment and channel losses but that the parameters necessary to implement that technology require further development.