Bedforms on the Lowermost Reach of the Tiber River (Rome, Italy): Preliminary Results from Integrated Geophysical Surveys and Samplings

An ultra high-resolution multibeam survey of the lowermost reach of the Tiber River (Rome, Italy) was carried out in February 2011 on a total length of 56 km from the northernmost part of Rome city to the river mouth. The morpho-bathymetric data reveal that the main morphological features of the river bed are widespread dune fields, covering about 45 % of the surveyed area. Three main types of bedform were identified, with wavelengths ranging from a few metres up to hundreds of metres. The seismic profiles show a transparent layer(s) of 1–2 m, corresponding to a traction carpet of coarse-grained sediment, where the bedforms migrate. By integrating bathymetric data with high-resolution seismic profiling and sampling, one can better define the genesis of these bedforms and provide insights into the present-day sedimentary processes acting on the river bed.