Semi-automatic detection of the overtopping waves and reconstruction of the overtopping flow characteristics at coastal structures

This paper proposes a semi-automatic and customizable procedure for the identification of the overtopping waves based on a threshold-down-crossing analysis of the sea surface elevation signals. The procedure can be applied to 2D experimental and numerical signals, to emerged and submerged structures, with the same accuracy of a human-supervised analysis. The procedure includes an original and innovative algorithm to compare the water level signals at consecutive gauges and couple the waves propagating in between. The coupling algorithm implies a series of original applications of practical relevance, such as: i) the computation of the wave celerity, which is a crucial parameter for the assessment of the structural stability and the hydraulic vulnerability of the landward area; ii) the estimation of the wave overtopping discharge, which can be obtained by integrating the wave celerities with the surface elevations; iii) the description of the wave overtopping characteristics and their evolution over the structure crest; iv) the evaluation of the volumes lost for percolation in permeable structures. The application to new and literature data and the comparison with well-established formulae prove that the results obtained from the identification and coupling procedures are accurate and reliable.