The Fluvial Dynamics of the Arno River

The paper illustrates the results of a study on the morphological, sedimentary and human characteristics of the Arno, one of the main rivers in central Italy. The analysis of historical maps, the sampling and grain-size analysis of the channel sediments and the geomorphologic surveying of the riverbed-alluvial plain system enabled us to reconstruct its evolution: like many rivers in central Italy, the Arno was affected over time by a progressive entrenchment, which is responsible for its present instability conditions. The causes of this entrenchment can be identified as: artificial reduction of the channel width and channelization works historically carried out; solid transport deficit, owing both to the building of sedimentary traps (such as the Levane and Laterina Dams) and to hydraulic-forest dredging works affecting the entire hydrographic basin; intense quarrying activity since the end of World War II which has affected the Arno’s riverbed.