Catchment water balance modelling in Australia 1960-2004

Computer simulation of the water balance of catchments for estimating runoff from rainfall began in Australia about four decades ago. It is now a mature technology with numerous models in use for design of agricultural and urban water supply systems, flood estimation, management of rural water resources for allocation and use, management of stormwater and wastewater in urban areas, and management of aquatic ecosystems. Only two models developed in the USA (Sacramento and Curve Number) are in common use in Australia, while several models developed in Australia are in common use. A majority of the models developed in Australia came from higher degree projects in universities. There are several instances of a model developed in one higher degree project forming the basis of a model in a later project. A significant feature of Australian work is the development of many simple models compared to the relative complexity of models developed elsewhere. Several substantial studies have attempted to relate model parameters to land use and establish procedures for use of water balance models on ungauged catchments, with little success. Almost all use of water balance models in Australia is where streamflow data are available for calibration of model parameters.