Evoluzione della piana di Sestri Levante (Liguria orientale) dal secolo XVIII alia situazione attuale

Evolution of the plain of Sestri Levante (Eastern Liguria) from the 18^th century to the present time

Abstract

The Peninsula of Sestri Levante, in Eastern Liguria, was formed, as proved by documentary evidence, during the 18^th century, when the seaward growth of the plain of the River Gromolo formed a littoral strip which established a link with the so-called «island», i.e. the rocky outcrop made up by the Upper Sandstone Formation on which stand the buildings known as «Castelli» and «Torre Marconi». After the emergence of the peninsula, which formed the roadstead of Sestri Levante to the West and the Bay of Silence to the East, the morphology of the littoral strip mentioned above began to evolve at its western side according to a pattern documented by surveys carried out between 1763 and 1987 A.D. (figs. 3, 4, 5, 6, 7, 8 e 9). This evolution, concerning only the part of the littoral strip facing the Sestri Levante Roadstead, is made up of a continuing seaward growth of the southern section and a corresponding gradual thinning out of the northern section, with a point of inflection located slightly to the north of the Gromolo mouth, in correspondence of the crossing of the streets Lungomare Descalzo and Via Veneto. The increase of the beach area in the southern section is estimated for the period 1763-1978 to be about 270 m²/year and is explained by the fact that since the formation of the Sestri Levante peninsula, at the western side of the latter, inside the bay bearing the same name, the wave trains of any sea type of the prevailing wind sector come ashore invariably with the same angle of incidence, thereby bringing about, in time, a constant West-East gradient of the littoral drift.