Hydrology of changing landscapes

The broad changes occuring in the Australian landscape since European settlement, their implications on water resources, and the significant investigations and research in that area are described. The effects of land clearing, fire, and the changeover from native vegetation to exotic pastures, trees and crops are interpreted in terms of water balance and altered soil properties. Examples of impacts on water yield, dryland salinity and erosion are given. The role and performance of mathematical models for predicting the effects of land-use change are described. Approaches for future investigations or research are given, placing emphasis on the need to extrapolate catchment behaviour on the basis of simple but sound physics, one process at a time.