An integrated approach to coastal erosion problems in northern Tuscany (Italy): Littoral morphological evolution and cell distribution

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.

River delta shoreline reworking and erosion in the Mediterranean and Black Seas: the potential roles of fluvial sediment starvation and other factors

“…The Chilia is currently the main mouth of the Danube, capturing about 58% of the liquid and sediment discharge of the entire Danube basin (Bondar and Panin, 2001;Tatui and Vespremeanu-Stroe et al, 2016). The mouth of the Arno has been strongly engineered, and this results in bedload trapping in its vicinity (Anfuso et al, 2011).…”

“…The history and development of deltas in the Mediterranean basin, one of the cradles of civilization, has been strongly intertwined with the rise and demise of cultures and societies, as well as with major cultural and economic changes, especially over the last -Stroe and Proteasea, 2015), Nile (Morhange et al, 2005;Ubeid, 2011;Ghoneim et al, 2015), Po (Simeoni et al, 2007;Simeoni and Corbau, 2009), Rhône (Sabatier et al, 2009) Ebro (Jimenez et al, 1997), Medjerda (Amrouni et al, 2014), Moulouya (Dakki, 2003), Arno (Anfuso et al, 2011), Ombrone (Pranzini, 2001). Directions for the Ceyhan are derived from delta plan-shape morphology in relation to the dominant local wave direction.…”

Beach Erosion in the Gulf of Castellammare di Stabia in Response to the Trapping of Longshore Drifting Sediments of the Gulf of Napoli (Southern Italy)

“…Human activities and coastal engineering works cause both direct and indirect transformations on coastal processes, having an environmental impact on the coastal system [16][17][18][19][20]. Therefore, these Geological map of Gulf of Napoli, southern Italy (after [5], mod).…”

Uncertainties in shoreline position analysis: the role of run-up and tide in a gentle slope beach

“…To support these activities, new defence structures have been built along some beaches, and although these structures have reduced local erosive effects, they have also increased erosion on neighboring coasts (e.g., Griggs, 2005;Stancheva et al, 2011;Manno et al, 2016). Coastal erosion is a relevant problem that involves both socioeconomic resources and private properties, and its assessment has long been an issue of international interest involving political decision-makers and researchers (Douglas and Crowell, 2000;Phillips and Jones, 2006;Anfuso et al, 2011;Rangel Buitrago and Anfuso, 2015). Historical beach evolution, erosion, and the retreat/accretion of shorelines have been analyzed using aerial and satellite images (e.g., Thieler et al, 2009;Fletcher et al, 2003;Genz et al, 2007;Anfuso et al, 2011;Dolan et al, 1980Dolan et al, , 1991.…”

“…Coastal erosion is a relevant problem that involves both socioeconomic resources and private properties, and its assessment has long been an issue of international interest involving political decision-makers and researchers (Douglas and Crowell, 2000;Phillips and Jones, 2006;Anfuso et al, 2011;Rangel Buitrago and Anfuso, 2015). Historical beach evolution, erosion, and the retreat/accretion of shorelines have been analyzed using aerial and satellite images (e.g., Thieler et al, 2009;Fletcher et al, 2003;Genz et al, 2007;Anfuso et al, 2011;Dolan et al, 1980Dolan et al, , 1991. Each remote image is often used to represent a year, and therefore the "shoreline" position identified and digitalized from each image becomes representative of all shoreline positions in that specific year.…”