The natural and man-induced subsidence of the Ravenna area, Po Plain

Abstract

The Ravenna area (south-east rim of the Po Plain, Italy) is subject to a high regional natural subsidence, near to the maximum values of all the Po Plain, active from at least the Lower Pliocene and during all the Quaternary. In the last decades Ravenna and its surroundings have been affected by a man-induced subsidence of up to fifty times the natural rate, mainly due to water pumping and to the extraction of methane. Since the 1960's the progressively widening of the land sinking has influenced the whole historical centre and the new industrial zones, as well as the coastline, few kilometers from the city centre. The subsidence reached peaks of high risk and the related effects became critical. The progressive reduction in the last two decades of underground water use brought the subsidence close to natural rates, but the negative consequences of elevation loss in the near future due to coastal erosion, higher storm surges and the risk of river floods, still remain.