Channel Width Variation Phases of the Major Rivers of the Campania Region (Southern Italy) over 150 Years: Preliminary Results

Abstract

In recent decades, rivers in Southern Italy experienced remarkable channel changes. Studies on this topic are relatively recent, and yet, far from defining a morpho-evolutionary trend that is common to all rivers of this area. The types and roles of the different controlling factors are still debated. In this study, we present preliminary results about the width channel changes of major rivers in the Campania region (Southern Italy) in the last 150 years. The aim is to provide new insights that are useful to define morpho-evolutionary trajectories at a regional scale and shed light on the roles played by controlling factors. To this aim, we carried out a GIS-aided geomorphological analysis of topographic maps and orthophotos. The results showed the existence of at least three main phases of channel width variations. Between the 1870s and 1930s (Phase 1), most of the rivers experienced widening. Between the 1930s and late 1990s (Phase 2), all of the rivers underwent dramatic narrowing at high rates. Finally, from the 1990s onwards, no dominant trend was found and variations were negligible. Land-use changes at the basin scale and rainfall changes at a decadal scale are likely the main controlling factors, while variations in human disturbances and local factors seem responsible for changes in general trends.

Land-Use Changes in the Sele River Basin Landscape (Southern Italy) between 1960 and 2012: Comparisons and Implications for Soil Erosion Assessment

“…Geomorphological literature also confirms the reliability of the results obtained in this study. In a recent paper, Magliulo et al [53] demonstrated that the main river that flows through the study area, i.e., the Sele River, experienced a channel narrowing by 36% between 1955 and 2011 (i.e., approximately the same period considered in this study), coupled with a reduction in transitional morphologies. Such kinds of river morphological changes are perfectly coherent with a reduction in sediment supply to the river from the surrounding slopes, i.e., with a reduction in soil erosion [17,18,52], such as that hypothesized in this study for the entire Sele River basin.…”

“…and 1886 m a.s.l. [53], with an average elevation of approximately 600 m [54]. Mountainous relieves account for more than 54% of the study area, while flat land surfaces accounted for 5.1%.…”

“…According to the method proposed by Rinaldi et al [56], the Sele River basin can be subdivided into three main physiographic units, i.e., (i) the Apennine mountain range, (ii) the low-altitude hills/alluvial valleys and (iii) the coastal plain [53].…”

“…At the top of these slopes, karstified remnants of ancient erosional landscapes are present [58]. In contrast, the hilly relieves shaped into the terrigenous deposits are generally gently sloping and gently rolling and affected by severe water erosion and mass movements [53]. Alluvial and slope deposits, often arranged into coalescent and/or telescopically arranged alluvial fans, connect the slopes to the alluvial plains.…”

Assessing the Morphological Quality of the Calore River (Southern Italy)

“…In the last century, and in particular, between the 1930s and the early 2000s, most of the Italian rivers underwent remarkable morphological changes. Two types of channel adjustments were observed, i.e., riverbed lowering, which is on average in the order of 6-7 m, and channel narrowing, in some cases up to 90% [1][2][3][4][5]. These processes had serious repercussions on the ecological conditions of the river corridor, which includes channel, floodplain, and recent terraces.…”