Small overtopping at Albufeira harbour: field measurements and modelling

Abstract

Overtopping evaluation is often performed by empirical methods that still require complementary validation against field measurements. This study presents the first data set of overtopping measured at a breakwater in Portugal, including flow depths, velocities and discharges. Data were collected for small overtopping conditions (lower than 1.24*10-3 m3/s/m) and compared with estimated values from empirical methods. The corrected NN_OVERTOPPING2 (corrected) tool proved to give reasonable estimations when the overall analyzed period was considered, while the uncorrected NN_OVERTOPPING2 and the EurOtop formulas were unable to adequately represent the measured discharges. Pn (normalized wave power) is suggested as a proxy to achieve discharge predictions using offshore wave parameters and the sea level (tide and surge).