Natural and Anthropic Middle-term Variations in the Delta System at the Mouth of the Goro River (Po Delta, Italy)

The modern delta system of the Po River is the result of an evolution strictly controlled by anthropic factors and mainly developed during a period of climatic deterioration (Little Ice Age 1550/1850). At the beginning of the 17th century the main branch of the Po River, Fornaci Po, was modified with the "Cut of Viro" in order to avoid landfill of the Venetian Lagoon. Simultaneously, the southernmost branch of Ariano, or Goro, was forced to flow southwards. Subsequent sedimentary variations, caused by changes in the climatic conditions, contributed to make the area supplied by the Goro Po River increasingly lagoonary. In the second half of the 19th century (end of the Little Ice Age - L.I.A. -), the first coastal spits started to take shape and developed in different systems throughout the entire following century. Coastal spits turned out to produce in the original bay, a progressive closure towards the sea. The strong decrease in solid loads, characterising the second half of the 20th century and mainly due to anthropic factors, marks the beginning of a new phase extending to the overall Po Delta system, in which the mouth layout is controlled by wave energy.