Predictions in catchment hydrology: An Australian perspective

Throughout Australia, there are strong regional differences in hydrological response to landscape and climate; however, in general terms, in Australian catchments the flows are typically peakier, base flows are of lower proportion, runoff coefficients are smaller, and dry periods are longer and more variable, than in European and North American catchments. In this context, this paper assesses the model types available to improve understanding and prediction of catchment flows and transport. Included in this is the concept of information and its influence on appropriate model complexity, as well as a characterization of the principal factors inhibiting model performance. The ability to predict the effects on flows and water quality of anything but major changes in climate and land use is limited. Improvement of understanding and prediction relies on the following: more rigorous testing of models to assess their ability to separate climate and land use effects on hydrological response; the use and improved interpretation of spatial data; more and better monitoring of hydrological response at a range of scales; complementary use of conceptual and distributed models; and integration of modelling with other information such as that from geochemical studies including tracer analysis.