Uncertainty Studies of Flash Flood Events on Ungauged Watersheds

Abstract

The rainfalls events with high intensity and short duration of the last years are urging necessarily to gauge steep-sloped small watersheds, and to recognise the behaviour of flash floods. In Hungary generally the watersheds are ungauged, where the classic analytical methods should
be used wary. Therefore properly analysing flash flood events need complex numerical models, or different stages of numerical models. In general floods from intense overland flow can be estimated with models using semi-lumped parametrization. The amount sensitive parameters can be reduced therefore the uncertainty of the model is also decreasing. On the other hand, during flash floods smaller uncertainties of volume and time could have an effects on a possible water damages. A useful tool for such investigations the use of hydrological and hydrodynamical model on watershed scale. An area averaged hydrological and a mesh based hydrodynamical model’s results can be compared on the outflow section. The goal of this study is presenting the usefulness of comparing different models.