Coarse-grained beach response after storms in three Italian sites

The storm response of three Italian mixed beaches is investigated. Two sites are located on the eastern side of the country (Portonovo and Sirolo) and one on the western side (Marina di Pisa). Portonovo and Sirolo are two mixed sand and gravel beaches (MSG) where the storms approach from two main directions (SE and NE). Marina di Pisa is a composite mixed beach subject to storms driven by SW. Gravel nourishments were undertaken in recent years on the three sites. Beach evolution was monitored measuring the same network of topographic profiles at a monthly to seasonal frequency. Beach orientation and the presence of protecting structures are the main reasons for the displacement and the accumulation of significant amount of sediments. In Marina di Pisa storm wave tend to pile material towards the upper part of the beach with no rotation of the shoreline. Sirolo and Portonovo act like pocket beaches with shoreline rotation that occurs after each storm in a clockwise or counter-clockwise direction. The wider and longer beach in Sirolo allows sediment to accumulate moderately during storms rather in Portonovo, given its longshore boundaries, the material tend to pile up in greater thickness. Periods of fair weather tend to decrease beach slope in Marina di Pisa and to increase beach width in Sirolo. After a big storm, in Sirolo and even more in Portonovo, the original beach configuration can be reached only after another storm of similar energy approaches by the opposite direction of the previous one.