Holocene fluvial and coastal processes, landforms and human settlement: the case of the roman town of Sena Gallica (Marche, Italy)

Sena Gallica (modern Senigallia) was the first roman colony established on the Adriatic Sea at the beginning of the 3th century B.C., in the northern Marche region, central Italy. Since 2010 a new research project has been started by an agreement between Municipality, University of Bologna (DiSCi, Section of Archaeology), University of Urbino (DiSTeVA) and Soprintendenza per i Beni Archeologici delle Marche, with the main goal to reconstruct the ancient landscape, understanding the relationship between geomorphological and historical evolution. The adopted research method is based on combining old and new data, involving archaeological excavations, topographical and geophysical surveys, geological and geomorphological analysis. The management of all acquired data is favoured by the digital field mapping, GIS elaboration and 3D modelling. The research revealed the presence of an early Holocene coastal fan built by the Misa river. The deactivation of this fan had been followed by a partial erosive dismantling by both wave and stream erosion and then by a partial drowning of its remains. The particular morpho-evolutionary history of the coastal fan allowed the development, in correspondence to the former fan-head, of soggy flats and depressions enclosing relatively high, isolated sectors, which later were selected for the earliest human settlement. The new environment was also modified by the fluvial action. In fact, the presence of topographic highs bounded by the Misa River meanders, and by the Penna streamlet, induced the roman colonists to found here the town. At the same time, the fluvial morphology influenced several choices in the roman urban planning, as in the case of the urban walls’ route, the location of the port, and of the regularization of the Penna channel, which was transformed in a kind of artificial channel, in order to prevent the floods of the Misa river.