Feasibility study for the use of alluvial sediments extracted from the Magra river drainage (Toscana) for coastal nourishment (Tuscany)
In the stretch of the Ligurian-Tuscan coast fed by the Magra river, shoreline retreat is mainly due to the excessive and reckless withdrawal of sand and gravel from the Magra riverbed occurred between the 1950’s and the mid-1980’s. If this withdrawal was triggered by the request of aggregates for building and road infrastructure construction, today it is necessary to reconfigure the longitudinal profile of the river in order to ensure its hydraulic effectiveness. That is an urgent action as a result of more frequent flood events caused also by climatic changes taking place with the consequent increase of extreme meteorological events.
The contrast to the first erosion occurrence was subsequently implemented through the construction of hard structural defenses that have contributed, over the long term, to further stiffen the coast causing the removal of sediment from the active beach profile and thus increasing erosion. The Tuscan area is featured by coastal infrastructures that have influenced the dynamics of the area, such as the Marina di Carrara harbor, but also by pressures mainly related to the use of coastal resources for tourism purposes.
How does the activity develop in Tuscany?
The objective is to get an integrated catchment and coastal sediments management, to be pursued through the drafting of a specific protocol and its implementation, for the reuse of alluvial sediments extracted from the Magra-Vara river system, including those accumulated in the artificial reservoirs. In addition, after recent flood events, strategic volumes of sand and gravel along the Magra river bed have become available. The objective is to plan dredging and transport to the related beaches in order to restore hydraulic effectiveness and beach sediment balance, after evaluation of their mineralogical, chemical and physical compatibility.