Author(s): S. Barbetta; L. Brocca; F. Melone; T. Moramarco
Keywords: No Keywords
Abstract: The knowledge of the flow discharge at a river site is necessary for planning and management of water resources as well as for monitoring and forecasting purposes when significant flood events occur. In the hydrological practice, the operational discharge measurement in medium and large rivers is mostly based on indirect approaches by converting stages into discharge using steady-flow rating curves. However, the stage-discharge relationships can be unknown for hydrometric sections where topographical surveys and flow velocity measurements, particularly during high floods, are not available. The purpose of this study is to assess the accuracy of a very simple model for discharge assessment at river sections where only the stage is monitored while the flow is recorded at different sites even significantly far along the channel, for which the contribution of the intermediate basin is significant. The model reliability is investigated for a river reach in the Tiber river basin, Central Italy, where three hydrometric sections are located and the rating curve at the upstream site is assessed starting from the discharge recorded at each of the two downstream sections. Moreover, several floods occurred along the Hron river reach, located in Slovak Republic, with different geometric and morphologic characteristics are also considered for the testing. The simulated discharge hydrographs are found in good agreement with the observed ones providing accurate rating curves beyond the available streamflow measurements. Finally, the model capability to take implicitly into account the unsteady effects is shown through experimental data recorded by ultrasonic flowmeter at a gauged site during a severe flooding event occurred along the Tiber river.