The aim of the presented doctoral thesis is the development of components for an operational flood forecasting system. Two methods to determine the rainfall-runoff relationship were applied in a case study in a small Alpine catchment: (i) Application of the raster-based hydrological model WaSiM-ETH. This model is based on the conceptual TOPMODEL- approach. Model parameters were determined by an inverse modelling algorithm; (ii) Application of artificial neural networks for a short-term runoff prediction. The study area was the catchment of the Zieplbach torrent in the Community of Westendorf, Tyrol, Austria. Discharge and precipitation measurements of this 1 km? catchment were available for the period from July 2000 until July 2003. This book is suited for hydrologists and hydraulic engineers using hydrological models or with an interest in data-driven approaches.