Progressive increase of inputs in floodplain delineation based on the DEM: Application and evaluation of the model in the catchment of the Opava River

Abstract

This contribution concerns the current stage of development of a practically applicable model for automatized delineation of the floodplain. The chief principle, which was added in the present model development stage, was application of the progressive change of model input parameters. The motivation of embedding of this principle was to converge the modelled floodplain to the situation and real properties of the floodplain. In particular, the progressively changing parameters were downstream increasing maximal relative height of the floodplain above the river level and downstream widening buffer zones of maximal floodplain width. The increase of the parameters is defined by a mathematical function. Partial automatization of the process in the ModelBuilder extension in the ArcGIS environment allows its application on the whole catchment at once, therefore it is suitable for floodplain delineation in vast areas, where the complete field mapping would be expensive or time-demanding, or where only partial field data are available. The model was applied in the catchment of the Opava River, and its results were compared to those of the previous stage model and also field-controlled on several localities. The conclusion from the verification is that the progressive change of parameters is a suitable technique that improves the model performance in previously problematic areas. There are, however, still some problems, particularly in setting of the model parameters.