The results of a study aimed at identifying and quantifying the geomorphological changes experienced by astrongly anthropized stretch of the Calore River (Southern Italy) between 1955 and 1998 are shown. This stretchis characterized by the presence of the town of Benevento and a high frequency of alluvial sediments extractionsites. The study was carried out by processing in GIS environment data derived from interpretation oforthophotos and maps, and from detailed field surveys. In Benevento, a large number of human infrastructuresthat, according to the existing literature, influence river dynamics, such as bridges and walls, are present.Moreover, in this stretch, all the extraction sites are currently active and sediments are withdrawn directly fromthe riverbed. The withdrawals started almost everywhere between 1955 and 1977.The data showed that, in 1955, the morphology of the river was of transitional type. During the examined period,the Calore River underwent a narrowing of ~75%. Field evidence such as exhumation of bridges and wallsfoundations and terracing of the floodplain that was active in 1955 revealed a lowering of the riverbed, probablystill ongoing. The amount of the lowering, not precisely quantifiable, could be of ~3-4 metres. It was also found adrastic reduction in the fluvial bars area, while their number increased significantly, except for point bars. Due tothese adjustments, the river morphology changed from transitional to single-tread with alternate bars. This resultis in agreement with literature data about most of the Italian rivers. Probably, the causes of the observedadjustments are connected to the drastic reduction of the liquid discharge, due to the Calore River springexploitation since late 50’s, and of the bedload transport induced by sediments extraction and, finally, to theeffects of bridges and walls. However, our data do not allow excluding an active role played by climate and/orland use change at the basin scale.
Short-term channel adjustments in an anthropized stretch of the Calore River (Southern Italy)
Valente A;Magliulo P
2013-01-01
Abstract
The results of a study aimed at identifying and quantifying the geomorphological changes experienced by astrongly anthropized stretch of the Calore River (Southern Italy) between 1955 and 1998 are shown. This stretchis characterized by the presence of the town of Benevento and a high frequency of alluvial sediments extractionsites. The study was carried out by processing in GIS environment data derived from interpretation oforthophotos and maps, and from detailed field surveys. In Benevento, a large number of human infrastructuresthat, according to the existing literature, influence river dynamics, such as bridges and walls, are present.Moreover, in this stretch, all the extraction sites are currently active and sediments are withdrawn directly fromthe riverbed. The withdrawals started almost everywhere between 1955 and 1977.The data showed that, in 1955, the morphology of the river was of transitional type. During the examined period,the Calore River underwent a narrowing of ~75%. Field evidence such as exhumation of bridges and wallsfoundations and terracing of the floodplain that was active in 1955 revealed a lowering of the riverbed, probablystill ongoing. The amount of the lowering, not precisely quantifiable, could be of ~3-4 metres. It was also found adrastic reduction in the fluvial bars area, while their number increased significantly, except for point bars. Due tothese adjustments, the river morphology changed from transitional to single-tread with alternate bars. This resultis in agreement with literature data about most of the Italian rivers. Probably, the causes of the observedadjustments are connected to the drastic reduction of the liquid discharge, due to the Calore River springexploitation since late 50’s, and of the bedload transport induced by sediments extraction and, finally, to theeffects of bridges and walls. However, our data do not allow excluding an active role played by climate and/orland use change at the basin scale.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
