Author(s): D’Oria Marco; Tanda Maria Giovanna
Linked Author(s): Maria Giovanna Tanda
Keywords: Confluence; Scale model; Two-dimensional numerical model; Calibration
Abstract: The paper refers to the study about the appropriate actions to undertake in order to avoid or to reduce the flooding of an urban area close to a river confluence located in the northwest of Italy. This area presents many buildings affected by inundation on occasion of flood events. According to the Froude similarity, an undistorted scale of 1: 40 physical model was constructed in order to estimate the water depths in the area during these events. The scale model showed a lack of conveyance of the rivers with the reference discharge. With the aim of a better design of the river reshaping actions, a 2D numerical model was implemented and calibrated according to the water levels detected on the physical model. As a first step a digital elevation model (DEM) of the scale model was generated by means of a photogrammetrical technique and used as the basis for the numerical modeling of the river bathymetry. Then the calibration of the numerical model was performed using the water depths measured in several points on the scale model. The calibrated numerical model was modified in order to simulate a river bed reshaping obtained from the removal of an existent weir and the lowering of part of the river bed. After an evaluation of the effects of different river modifications and the identification of the most performance reshaping, the new river configuration was tested on the scale model. The water surface elevations evaluated by the 2D mathematical model were in a good agreement with the ones measured on the scale model. The present study confirms that a 2D numerical model can be used as a support or even as a substitute for a physical model in the evaluation of the different strategies useful for the reduction of inundation damages involving complex river reaches.
Year: 2007