Geomorphology of the Lower Calore River alluvial plain (Southern Italy)

Abstract

ABSTRACTA 1:18,000-scale geomorphological map of the Lower Calore River alluvial plain (Southern Italy) is here presented. The area strongly suffered the dramatic effects of a destructive flood on 15 October 2015. The presented Map was produced in a GIS using topographic maps dating from 1870, 1909, 1936 and 1955 and 1:10,000-scaled colour orthophotos from 1998. All the maps and aerial photos were georeferenced in the UTM33 WGS84 coordinate system. The detected landforms were manually digitized and checked in the field. A geodatabase containing attributes such as type, age and surface area of each landform was created and progressively updated. The areal and unconventional map legend was designed to provide maximum readability. In the alluvial plain, five orders of river terraces were recognized. They are separated by strongly reshaped, gently sloping, inactive fluvial scarps (FS), less than 1.5 m high. Former channels, now abandoned, were also mapped. The confluence migrated eastward/east-northeastward between 1870 and 1955, followed by a north-northwestward migration between 1955 and 1998. Finally, numerous riverbank failures were observed and mapped along the active FS. A secondary map showing the age of the alluvial plain was also produced and showed that most of the investigated alluvial plain formed between 1909 and 1936. The study also shows the results of channel adjustments experienced by the river in ∼130 years.