As low crested structures we mean structures which are regularly overtopped by waves; most artificial structures of this type along European shores are constructed with rubble mound jetties, the analysis is restricted therefore to this type of structures and to natural boulder reef as term of comparison.

The principal expected achievements are:

• To provide a reduced set of parameters describing synthetically the effects of defence structures from the different points of view.
• To provide validated and calibrated models able to foresee effects of low crested defence structures on the littoral environment.
• To provide a predictive model for expected ecological scenarios in consequences of different breakwater configuration and local/regional environmental conditions
• To provide tools able to foresee effects of social and economic relevance, including the public reaction to defence structures and benefits to tourism
• To provide clear guidelines for the design of low-crested structures to local authorities planning shore defence measures.