Predicting hydrologic response from physio-climatic attributes : an application to ungauged sub-catchments of the Burdekin River, North Queensland

The Burdekin is a large (140,000 km2) catchment located in the dry tropics of North Queensland, Australia. To assess the water resources of this catchment, we require a methodology which will allow us to determine the daily streamflow at any point within the catchment. To this end, we have utilised a simple, lumped parameter model, IHACRES. Of the five parameters in the model, three have been set to default values, while the other two have been related to the physio-climatic attributes of the sub-catchment under consideration. The parameter defining total catchment water yield (c) was constrained using %yield, which is related to summer precipitation, while the streamflow recession time constant (τ) was related to the total length of stream reaches in the catchment. These relationships were applicable over a range of scales from 68 km2 to 130,000 km2, however three separate relationships were required to define c in the three major regions of the Burdekin – the upper Burdekin, Bowen, and Belyando Suttor. This research has provided a valuable insight into the hydrologic behaviour of the Burdekin catchment, while also providing a useful methodology for water resources assessment. The invariance of the relationships with scale indicates that the dominant processes may be similar for a range of scales, while the fact that different relationships were required for each of the three major regions indicates the geographic limitations of this regionalisation approach.