Pranzini, E. and Rosas, V., 2007. Pocket beach response to high magnitude – low frequency floods (Elba Island, Italy). Journal of Coastal Research, SI 50 (Proceedings of the 9th International Coastal Symposium), 969 – 977. Gold Coast, Australia, ISSN 0749.0208

A megaflood, with an estimated recurrence time of approximately 200 yr, affected the Elba Island in September, 2002. In several pocket beaches, active and reactivated creeks discharged a huge volume of unsorted sediments to the coast. Since the morphological and sedimentological conditions of one of these bays (Gulf of Procchio) was known due to topographic and sedimentologic studies performed in 1999, the impact of this event was easily evaluated through a survey performed a few days after the flood. The main beach responses were the formation of ring deltas, the increase of the fine fraction in the nearshore sediments and the coarsening of those in the swash zone.

A further survey in 2004 allowed monitoring the recovery of the beach, which is still returning to the pre-event conditions, at a slow rate. Although only the widest delta among those formed is still identifiable on the shoreline, and in spite of the nearshore sediments having lost all the fines, gravel and cobbles are still present from the step to the berm crest in the sectors adjacent to the old outlets and gravel is moving alongshore. The erosion that affected some pocket beaches at Elba during the second half of the 20th century, firstly attributed to the agriculture abandonment and to the consequent forest recovering, now has a new or additional cause: the return of the bay to pre-flood conditions within cycles of catastrophic accretion followed by mild erosion.