Bathymetric variations in a reach of Po River (Northern Italy) during channelization works -abstract

The results of a study on the evolution, between 1919 and 1946, of a segment of the river PO morphology are presented In this period the first phases of the realization of an enormous channelization project were carried out. The project was aimed to allow the complete river navigation. In 1919 the Po river had a braided pattern. The aim was to create a sinuous river, with well defined mender lengths. This obviously would have implied a massive movement of material since the river would have had to move far from the current position. The cost would have been not sustainable. Engineers decided to take advantage of the high potential mobility of the river. They start to create some current deflectors that move the flow towards the opposite river side and determine bank erosion. The deflectors had been progressively lengthened until the river reached the planned bend length. At that moment, they started to protect the opposite eroded bank with another deflector. This process was carried out contemporary along different segments of the river The project was continuously monitored and a lot of bathymetric maps of the river had been created in the period 1919-1946 for a 40 km reach length. Using this technical cartography we have digitised the main morphological characters of the river (bars, channel, banks), and the same was done for the bathymetric lines The obtained data was used to perform a volumetric analysis and to evaluate the morphological variations of the River.