Failure of the nourishment intervention at Ladispoli Beach (Central Latium coast, Italy), Part 1: an insignificant episode during the last 70 years of coastal evolution

Abstract

Based primarily on morphological and sedimentological data from different periods, this study focuses on the recent evolution of a coastal stretch near Rome where human activity has impacted significantly on natural processes during the last 70 years. This coastal stretch, home to the city of Ladispoli, underwent erosion from 1955-1960 after a long period of stability. Erosion was very active in the western part of the coast, where a cuspate foreland was dismantled during the rollover inland migration of the littoral system following a sharp reduction in sediment budget. In its eastern wing, erosion was counteracted initially (around 1970) by hard interventions and later (2003) by beach nourishment whose benefits did not meet expectations. In fact in the first year of wave exposure, most of the fill sand placed on the dry beach was eroded and transported seaward, generating a nearshore-submerged deposit. The beach widening was in total very modest highlighting the failure of this intervention. These rapid changes were followed by a phase of slower morphological re-adjustments under the control of the progressive revitalization of the prevailing environmental conditions. During this phase, the shoreline retreated further reaching its pre-nourishment position approximately in 2006, whereas the submerged deposit lasted a few years longer before being dismantled. The last ten years of evolution, unaffected by any residual nourishment influence, were marked by some attempts to mitigate erosion by several small hard interventions. Despite these attempts, the coast appears today as it was before nourishment, with the same degradation and sediment paucity and with a modest opposition to extreme events.