Physically-based River Basin Modelling Within a GIS: The LISFLOOD Model

Although many GIS are very advanced in data processing and display, current GIS is not capable of physically-based modelling. Especially simulating transport of water and pollutants through landscapes is a problem in a GIS environment. A number of specific routing methods are needed in a GIS for hydrologic modelling, amongst those numerical solutions of the Saint-Venant equations, such as the kinematic wave approximation for transport of surface water in a landscape. The PCRaster Spatial Modelling language is a GIS capable of dynamic modelling. It has recently been extended with a kinematic wave approximation simulation tool to allow for physically based water flow modelling. The LISFLOOD model is an example of a physically-based model written using the PCRaster GIS environment. LISFLOOD simulates river discharge in a drainage basin as a function of spatial data on topography, soils and land cover. Although hydrologic modelling capabilities have largely increased, there is still a need for development of other routing methods, such a diffusion wave.