Hydrological analysis of a flash flood across a climatic and geologic gradient: The September 18, 2007 event in Western Slovenia

Extreme flood response to short-duration convective rainfall in South-West Germany

“…Also, the values reported for Rangendingen are in the range of those computed for other 8 surveyed catchments. Overall, this support the view that runoff ratio estimates obtained in this work are robust and may provide an indication for runoff generation triggered by short and intense rainfall in small to medium rural catchments in Central Europe (Zoccatelli et al, 2010). …”

“…This flood was very long and composed of several peaks; as a result, the estimation of runoff ratio is subject to significant uncertainty. The analogy in terms of runoff ratio of the However, one should note that these values are in the range of those reported for specific small and medium size catchments and for events characterized by short rain durations in Continental Europe (Zoccatelli et al, 2010). When considering these events, it is apparent that the rainfall duration is an important control on runoff ratio, with initial losses accounting for an important contribution to the overall losses.…”

“…Information concerning the timing of the main hydrograph feature was based on eyewitnesses' assessment. Uncertainty analysis of this kind of information based on multiple crosschecked interviews shows that the timing of specific flood hydrograph features may be accurate within ±20 min (Zanon et al, 2010). Accordingly, the channelization support area (A s ) is found equal to 2.43 ha, v c is equal to 3 m s −1 and v h is equal to 0.05 m s −1 .…”

“…The hydrological model is described in detail in Zanon et al (2010) and only an outline is provided here. The discharge Q(t)is computed by the model at any location along the river network as follows:…”

Spatial moments of catchment rainfall: rainfall spatial organisation, basin morphology, and flood response

“…The model parameters were estimated over the catchments available for each event by means of a combination of manual and automatic calibration to minimize either the Nash-Sutcliffe efficiency index over the flood hydrographs (for the gauged catchments) or the mean square error over the flood peak and the timing data (rise, peak and recession) (for catchments where runoff data were provided from post-event surveys). Details about the application of the model to the individual events, its calibration and its verification are reported in the relevant papers (Sangati et al, 2009;Zanon et al, 2010). In general, the model simulations of the flood hydrographs were closer to observations for the smaller basins where the linear routing approach implemented in the model provides a better description of the actual processes.…”