Channel Changes and Controlling Factors over the Past 150 Years in the Basento River (Southern Italy)

Abstract

Channel changes are receiving growing interest in relation to the relevant implications for river management and restoration. In this kind of analysis, purely qualitative approaches have been gradually replaced by quantitative approaches aimed at reconstructing the temporal variations in parameters (e.g., channel width and depth) to investigate not only the evolutionary trend of the river but also the possible cause-effect connections. This paper investigates the channel dynamics in the Basento River (Basilicata Region, Italy) over the past 150 years, when the river was heavily affected by human activities (e.g., hydraulic interventions and gravel mining) and climate changes. Channel adjustments were analysed with historical maps, aerial photos, and geomorphological surveys. The results show that the channel underwent a strong narrowing during the twentieth century, similar to many rivers in Italy, with the most intense phase from the 1950s to the 1990s (with the width varying from −30% to −80%). The morphology pattern remained almost completely unchanged, apart from a few reaches located in the hilly area that were affected by intense modifications before the 1940s. The causes of channel adjustments were identified as human disturbances (land use variations, channel interventions at the reach scale, sediment mining) from the end of the 1800s to present, as well as natural factors (changes in frequency, duration, and intensity of flood events), whose effects have intensified since the late 1990s.

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

“…In the case of the 1949 flood, Magliulo et al [2] clearly documented such widening for the Tammaro River, but Figure 2 shows that no similar effects are evident for the larger and longer Calore River. Furthermore, the case of the Calore River is similar to those of the Arno [42] and Basento Rivers [11], as both these rivers experienced catastrophic floods during phases of intense narrowing. In both cases, the authors did not report evidence of channel widening strictly associated to these extreme floods [11,42].…”

“…Furthermore, the case of the Calore River is similar to those of the Arno [42] and Basento Rivers [11], as both these rivers experienced catastrophic floods during phases of intense narrowing. In both cases, the authors did not report evidence of channel widening strictly associated to these extreme floods [11,42]. Thus, it is possible that widening induced by catastrophic floods during phases of channel narrowing could be more evident and intense on relatively smaller rivers (such as Tammaro River) than on larger ones (such as Arno, Basento and Calore Rivers), where they could be more easily obliterated.…”

“…The second phase of channel mean width variations (Phase 2) was common to all investigated rivers, which experienced dramatic narrowing that occurred at high or very high mean annual rates (Figures 2, 5 and 7). Such narrowing affected all of the Italian rivers [2,[5][6][7][8]10,11]. In the Campania Region (Southern Italy), this phase occurred when a diffuse reforestation affected the slopes; thus, likely reducing sediment supply to rivers, especially during dry periods (i.e., middle 1940s-early 1960s and late 1970s-early 2010s [18,23]) (Figure 7).…”

“…An almost total lack of information existed for rivers in Southern Italy, at least up until the early 2010s, which is different from rivers located in northern and central part of Italy [5]. Recently, several papers partially filled this gap [2,[6][7][8][9][10][11]. In particular, Scorpio et al [7] compared the channel changes experienced by some rivers located in the different regions of Southern Italy during the last 150 years, and observed three distinct phases of channel adjustments.…”

Spatiotemporal Evolution Trajectory of Channel Morphology and Controlling Factors of Yongding River, Beijing, China

“…The plane shape of a river can be determined quickly and accurately through remote sensing data. Remote sensing has advantages, such as a short repetition period, high resolution, and less work, for the monitoring of research areas on a large spatiotemporal scale [26]. Research on river evolution trajectories based on remote sensing images has been carried out since the early 1940s.…”