A challenge to make conscious decisions along the coast: the Team COSTE’s approach

The preservation of the coast is a major challenge that any littoral municipality needs to face in the new millennium. In the past decades the coastal erosion issue was often addressed with the construction of hard protection structures (e.g. groynes and breakwaters), sometimes without taking into full account the consequences on the adjacent sectors of the coast. Artificial replenishments were also frequently used to nourish suffering beaches: even though they were deemed as a softer approach relative to groynes and breakwaters, beach fills were still intended to fix a local problem. Therefore, scientists, decision-makers, stakeholders must mutually adapt to a paradigm shift: the evolution of the coastal environment is not just affected by the processes acting along the shoreline, but also along river courses and offshore. The coastal system must be analyzed in a cross-shore sense from the drainage basin to the sea, but that is not enough: on regard to the longshore sense, a wise and effective coastal management depends on a strong and influential governance that might be able to cross the administrative limits, thus allowing to consider the erosion issue in terms of littoral cells and no more just locally. The transversal scale (the “source-to-sink” approach) is paramount because a crucial question still without answer is how much sediment is delivered by rivers to the coast; in turn, how much of this sediment is further displaced offshore to a depth where no process is able to bring it back to the beach. Without a reliable value, sediment budget evaluations cannot be consistent nor trustworthy. Nonetheless, the longitudinal scale must be addressed in terms of physiographic unit: too often the beaches have been managed locally, basically overlooking the consequences of any kind of intervention may induce on the adjacent sectors of coast. A wise plan to counteract the erosion effects and to a further extent to manage the coastlines includes a proper redistribution of the sand, which must not depend on the administrative limits of municipalities. In all this, the collaboration between any social layer should be particularly stressed: sharing knowledge and setting up actions involving universities, local governments, stakeholders, professionals, schools, and citizens must be the focal point to make conscious decisions in accordance with the precautionary approach and to efficiently counteract the erosion issue along the coast. In an effort to achieve all the above mentioned targets and goals, the Department of Geosciences of the University of Pisa has recently reached an agreement with departments from the other Tuscany universities, Firenze and Siena, for a mutual collaboration with the purpose to proficiently cooperate and to share knowledge and results about coastal processes and management. The so-called Team COSTE agreed to accept the concept of the transversal and longitudinal scale to address any issue related to coastal processes and management: the “coast system” can be really understood only if knowledge about the three sectors “drainage basin – coast – sea” increases collectively and not separately. A multidisciplinary approach was perceived as the best to gain immediate results: the groups affiliated to the three Tuscany universities put into effect the collaboration sharing knowledge, equipment and low-cost technologic solutions.