Pier Luigi Aminti

Marina di Cecina Urban Beach: a Shore Protection Project

ABSTRACT AMINTI, P.L., BARTOLETTI, E., BERRIOLO, G., BINI, A., BONINSEGNI, G., MORI, E., PRANZINI, E and VANNUCCHI, V., 2011. Marina Di Cecina Urban Beach: a Shore Protection Project. In: Micallef, A. (ed.), MCRR3-2010 Conference Proceedings, Journal of Coastal Research, Special Issue, No. 61, pp. 282–289. Grosseto, Tuscany, Italy, ISSN 0749-0208. Marina di Cecina is a tourist town built on the southern side of Cecina river mouth. Its urban beach has been undergoing severe erosion since the early 20th century as a consequence of reduced river sediment input. Some groins were constructed after the collapse of the first line of houses near the waterline. Immediately the shoreline assumed a characteristic saw-tooth shape and beach use and recreational facilities had to adapt to this uneven sand distribution. In 1990 two of the three main groins were extended with submerged segments and limited artificial nourishment was also performed. Some discontinuous submerged detached breakwaters were added later within the groin field, which resulted in sediment dispersion offshore. The beach was maintained with occasional nourishment, but its width could not support profitable recreational activities and some tourism facilities are still being damaged today by waves during severe storms. To solve these problems, the Livorno Province administration within the Regional shore protection plan, has performed a rehabilitation project at this urban beach. The project is based on the reconfiguration of the whole defence system, removing parallel structures and modifying the groin field; varying the lengths to reach a new alignment of the tips, in order to stabilise a new and more uniform beach to be obtained by means of artificial nourishment. Groin tips will be asymmetric, to reduce wave reflection on the exposed side; some of them will be extended with a long submerged segment made with T-shape concrete precast elements. Groins will be constructed using large flat-faced stones in order to obtain regular slopes, whereas a central pathway made of concrete will allow easy access to pedestrians. Moreover, at the extremities of the field, where parking facilities are present, groins will end with a mildly sloped ramp to give wheelchair users access to the sea.

Cecina Specially Protected Zone: a Shore Protection Project

ABSTRACT AMINTI, P.L., BARTOLETTI, E., BERRIOLO, G., BINI, A., BONINSEGNI, G., MORI, E., PRANZINI, E and VANNUCCHI, V., 2011. Cecina Specially Protected Zone: a Shore Protection Project. In: Micallef, A. (ed.), MCRR3-2010 Conference Proceedings, Journal of Coastal Research, Special Issue, No. 61, pp. 96–103. Grosseto, Tuscany, Italy, ISSN 0749-0208. The coast north of River Cecina mouth hosts Tombolo Settentrionale Specially Protected Zone (ZPS, according to the 79/409/CEE directive) and is constituted by linear or hummocky dunes covered by pine forest. The beach had been severely eroded since the beginning of the 20th century due to reduced river sediment input and the construction of several shore protection structures (groins and rip-raps) lack a general masterplan. Although this coastal segment is mostly used as a free tourist beach, there are a few restaurants and bathing facilities whose owners made projects in order to defend such structures, having increased erosion in the neighbouring areas. A coastal road was demolished by waves in the 1980s and dunes were continuously exposed to wave action. In the early 1990s, the Livorno Province administration funded a shore protection project based on groins with a submerged extension, and nourishment with sediments quarried within the Cecina River alluvial plain. This project was supported by a limited budget, and in spite of resulting in an effective stabilisation of the coast, it did not lead to significant beach rehabilitation considering tourism purposes. Due to the Regional Shore Protection Plan, Livorno Province has now financial resources for obtaining a fuller coastal rehabilitation in this area, providing more uniform shaping to the shoreline and reducing the visual impact of emerged structures. All seawalls will be removed (except for a few placed to protect adjacent tourist facilities) and the number of groins will be reduced. The latter will be realigned and many of them will be extended, with a long submerged part in order to favour the sedimentation of sand moving in the surf zone, whereas beaches will be enlarged by means of artificial nourishment. The project considers also the impact a new marina, planned at Cecina river mouth, will have on the coast.

REHABILITATION OF HIGHLY PROTECTED BEACHES BY USING ENVIRONMENT-FRIENDLY STRUCTURES

In the last few years, environmental impact has been one of the most discussed topics in Coastal Engineering. Actually, conferences on subjects like “soft shore protection” or “environment friendly-structures” have been held all over the world. However, there is still not a general agreement on what environment-friendly means for a coastal protection structure. In this work we try to give a better clarification of this subject by showing some relatively new coastal protection structures that can be considered environment-friendly. Results from laboratory experiments, numerical simulations and field experiments are reported. Concerning Low-Crested Structures (LCSs), laboratory experiments on the piling-up phenomenon are presented. Numerical simulations of flow field around a submerged groin and the morphodynamics measured by field monitoring are discussed. Finally, two case studies of gravel nourishment and their effectiveness are described.