Flash flood event (October 2010) in the Zinzolo catchment (Calabria, southern Italy)

Abstract

This work aims to describe the flash flood event occurred between 18 and 19 October 2010 in the Zinzolo basin. The Zinzolo basin is located on the Tyrrhenian side, along the northern edge of the Capo Vaticano promontory (Calabria, southern Italy), close to the Tropea village. The drainage area is mainly made up of granitoids, often strongly altered and therefore easily erodible. The geomorphic condition of the drainage network shows low hierarchy degree and downward concavity of the hypsometric curve. These features suggest that the Zinzolo basin is in a juvenile stage and subject to significant modifications, favouring abundance of detritic material in the drainage network. Therefore, small-scale basin, steep slopes, steep bed gradient, widespread instability and high solid loads in the drainage basin, are the main causes of a high predisposition to events of flash-flood type in the Zinzolo basin. The rainfall analysis between 18 and 19 October 2010, shows that in these two days has been recorded (in 6 hours) the highest historical rain event for that area. As a result, the abundant water mixed to detritus have overflowed the banks of the stream in the buried part of the river bed, producing significant damage and hydrogeological hazard in the inhabited riverside areas.