Modeling the effects of land use change

The recent experience in Australia and elsewhere is that the successful implementation of catchment management strategies is increasingly dependent on an ability to model the impacts of land use change and in particular urbanization. The XP-AQUALM package for modeling stream flow, water quality and best management practices ha been implemented under the EXPERT (XP) environment. The package was developed from a range of simple, robust models which have been integrated into a single package. The features of XP-AQUALM include: 1) a rainfall/runoff model, 2) point source and non-point source export models, 3) a gross pollutant trap (GPT) model, 4) a water pollution control pond model, 5) a lake loading model, 6) a river quality and loading model, and 7) graphical user interface and embedded decision support system which combines all the above models in a networked environment. Two case studies which overview the application of the XP-AQUALM model to a coastal river and land use system and the catchment of an inland lake as part of the formulation of catchment management strategies which were based on ecologically sustainable development principles are presented. The modeling approach including model calibration adopted in response to the differing availability of water quality data and the application of ESD principles to the setting of sustainable loading limits is also discussed. It is concluded that XP-AQUALM is an easy to use, yet powerful tool for the analysis and formulation of integrated catchment management strategies.