Sea Bottom Scour Near Gaps in Coastal Protection Structures

A systematic survey curried out along the most important coastal protection structures of Tuscany, shows that some years after the construction, important morphological changes occur on the sea bed near the structures. Very deep scours have been measured near the gaps between detached breakwaters, and generalized sea bed deepening occur in front of submerged and emerging barriers. Gaps due to interruption of construction works resulted in deep scouring after only a few months causing a significant increase in project coast. Numerical models were used to examine the scouring process in front of submerged structures and at the gaps; a physical model was carried out to examine scour formation and how this phenomenon causes the instability of breakwater heads. In this paper, different coastal protection schemes on the Italian Coast have been studied focusing on long term changes on sea bottom profile due to coastal structures.