Experimental Research on Floodplain Storage Inundation: Preliminary Results

Among control structures in flood management, floodplain storage represents one of the most effective measures, since they hold part of flood volume into a delimited area, thus reducing the peak discharge. One-dimensional models are quick and practical and are often based on the hypothesis of horizontal water surface in the floodplain during storage filling. This assumption need to be verified by means of experimental test, which are really difficult to assess also because tests requiring many costs to achieve prototypes and physical models. To this aim the present paper shows preliminary results of an experimental investigation to assess the reliability of level pool routing in design of on-stream floodplain storages. Experimental tests performed with reference to on-stream floodplain prototype, showed that assumed hypothesis is correct during storage filling. Results obtained by means of numerical model based on level pool routing hypothesis are very near to experimental measures. Furthermore two synthetic indexes, which characterize hydraulic behavior of floodplain storage, were calculated for each test. It is shown that very simple linear relationship exists between these two indexes exists so this linear equation can be easily used to define the storage volume in preliminary design.