| dc.description.abstract | Occupation of the coast has significantly increased in recent decades, mostly due to a greater demand for
recreation and tourism. Today, erosion threatens many human-made structures and activities, requiring an
integrated approach for the understanding of coastal dynamics and identification of alternatives to associated
problems. This study investigates a 64 km-long coastal physiographic unit in the northern microtidal littoral
of Tuscany (Italy). Vertical aerial photographs and direct field surveys were used to retrieve changes in
shoreline position over 1938–1997 and 1997–2005 time intervals. Significant beach accretion was observed
during the first period updrift of Carrara (84 m) and Viareggio (280 m) harbours and at Marina di Pietrasanta
(100 m), whereas severe erosion occurred downcoast of Carrara harbour (−130 m, at Marina dei Ronchi) and
on the northern side of Arno river mouth (−400 m). Similar trends were observed between 1997 and 2005;
beach slope between the 1997 shoreline position and the closure depth correlated well with the distribution
of erosion/accretion patterns from the 1938–1997 period (slopes were lower in eroded areas than at sites
under accretion). Longshore distribution of erosion/accretion patterns was controlled by coastal compartmentalisation.
Three of the main littoral cells were mostly formed by natural limits (i.e., Punta Bianca
promontory, Marina di Pietrasanta, the Arno river mouth and the port of Livorno). Several sub-cells were
created within these cells due to the introduction of human-made structures (such as Carrara and Viareggio
harbours), which formed artificial fixed limits that allowed the transport of sediments (exclusively fines) in
one direction only. Results will help improve the understanding of coastal processes and manage littoral
sediment transport in a sustainable manner. This will reduce the need for structural interventions, such as
breakwaters and groynes, which in the past decades prevented coastal retreat at local scale but shifted erosion
downdrift, leading to degradation of the investigated area and requiring continuous maintenance. | en_US |