Regional variability of coastal dunes observed along the Emilia-Romagna littoral, Italy

- Understand the evolution of the coastal dunes of the Emilia-Romagna littoral.
- The use of factor analysis could represent a useful tool for coastal managers.
- 4 groups of dune related to the level of anthropization have been identified.
- The existing models are useless to describe the evolution of the coastal dunes.
- Human interferences need to be further analyzed in order to elaborate or improve some models.

The knowledge of the evolution and conservation of the coastal dunes inside a beach-dune system is fundamental for their protection and for appropriate coastal management. We analyze and classify the coastal frontal dunes present along the Emilia-Romagna according to beach and dune characteristics as well as human activities by using aerial photographs and field measurements. Aeolian sand transport was calculated using a simple predictive equation. The results show that 62 coastal dune systems extending for 31 km are still bordering the 130 km coastline of the Emilia-Romagna region and we observe an alongshore variability of the dune's characteristics. This variability is controlled by the sedimentary budget, beach orientation to the wind-wave direction and human impacts. Four groups of frontal dunes are identified through factorial analysis: two groups are natural dunes, while the other two display characteristics that demonstrate the consequences of human activities. However, the dunes that present the worst conditions are natural dunes corresponding to regressive forms. It also appears that human intervention, when the human impacts have cancelled the original characteristics of the dunes or have obstructed the formation and growth of incipient dunes, have allowed their conservation and protection. We therefore suggest that the dunes presenting the worst conditions, which are often bordered by a narrow beach, need to be protected, considering that the most efficient protection of the dune is provided by a wide, stable beach. This highlights how successful beach nourishment has a positive impact on the foredune's systems favoring their development and conservation.