Monitoring beach nourishment based on detailed observations with video measurements

Abstract

Monitoring the performance of beach nourishment is necessary to test its usefulness and improve its efficiency. In summer 2002 Barcelona city beaches (NW Mediterranean, Spain) were nourished after a very energetic period that produced widespread beach erosion. In this study two of these beaches –La Barceloneta and Bogatell- were monitored for a year and a half after the filling (i.e., the moment when the beach area reached values similar to that before the nourishment) using video image measurements to examine their behaviour. The nourishment in La Barceloneta beach produced an increase of the emerged area of 5000 m2 with a mean advance of the shoreline of 14 m, whilst in Bogatell, the area increased by 12750 m2 and the mean advance of the shoreline position was 20 m. The video monitoring allows assessment of the effect of individual storm events that would be missed with traditional survey methods. The recorded storms caused mainly beach rotation but did not significantly reduce the beach area overall. After the nourishment both beaches showed a reduction in their beach areas with mean losses, calculated for a year and a half later, of 22 m2/day in La Barceloneta and 18 m2/day in Bogatell