Assessing of detached breakwaters and beach nourishment environmental impacts in Italy: a review

Coastal regions are exposed to natural phenomena such as sea waves, sea level rise, climate change, and flooding events. These factors, along with human pressures, lead to an increase in coastal erosion. In response, hard engineering measures were realized as breakwaters and groins, to oppose erosion processes along the sandy beaches of the Italian coastline. These types of defense systems showed negative impacts on landscapes, ecosystems, and expected results. Additionally, the use of coastal revetments, submerged sandbars, soil bioengineering, and beach nourishment projects were used to defend seaboard areas from the risk of a growing shore withdrawal. Among these soft solutions, beach nourishment is becoming an environmentally friendly method to control shoreline erosion, increasing the width of sandy beaches to guarantee a better tourist use of coastal regions and to add a greater buffer between the shoreline and existing infrastructure. In recent times, nourishment projects have been combined with other protective measures, such as submerged sandbars and underwater detached breakwaters, limiting the loss of sediments from sandy beaches and allowing better protection from stormy events. These mixed solutions ensure effective coastal protection by maintaining the width of sandy beaches for tourist use, guaranteeing the environmental safeguard of the coastal ecosystems. In order to achieve the best result with these types of projects, a close collaboration between coastal engineers, geologists, biologists, and policymakers toward integrated coastal zone management is necessary. The study described in this paper has taken the form of a literature review regarding both the negative environmental impacts and the benefits associated with the use of old and new coastal defense systems.