Officially justified as a measure designed to stem as far as possible the gradual silting-up of the lagoon, in reality this great artificial river bed was intended, as far as hydraulic science could predict at the time, to transfer and offload into the Goro bay a major proportion of the problems and risks which had hitherto affected the Veneto delta, but which would now bring additional complications to Ferrara.
But let us consider how and why this happened. Venice had fallen into ever increasing difficulties after the discovery of America, which caused a considerable proportion of the mercantile traffic previously handled through Venetiancontrolled Mediterranean ports, and on Venetian-owned ships to divert to the Atlantic ports. As a result she was increasingly unwilling to allow the ports of Ferrara (and in particular that at Goro) to continue to monopolise a significant proportion of the river transport (shorter and hence cheaper) of goods to and from Lombardy.
Further, Venice also feared that - with the now certain and imminent 'devolution' of Ferrara to the Papal States, which finally occurred in 1598 - the port of Goro might also become a military outpost for a neighbour much more fearsome than its predecessor. And it might become even more terrible - as Venetian ambassadors reported to their Senate - if the fortress town long planned by the Este were finally to be built around the far from distant Castello della Mesola.
The sources available suggest that these were the real reasons for the "cut" from Porto Viro, the chief effect of which would be the inevitable silting-up of the bay of Goro and the consequent ruination of its port. All of which did indeed come to pass within a few years, accompanied by yet further serious consequences for the area to the north east of Ferrara.
In his 1660 Atlante del Ferrarese the Ferrara map maker Alberto Penna recorded the impact of the Porto Viro 'cut' during the time of the Papal State. As well as the devastating silting-up of a major part of the bay of Goro and three ports overlooking it (the ports of Abate and Volano as well as Goro port itself), the drainage network on the 35 000 hectares of land reclaimed some thirty years earlier by the Este family also suffered severe damage.
This drainage network all but disappeared, returning the land to its original sterile state. The landscape was destined to remain in this condition for two hundred years and more; it was only towards the end of the 19th century that a fresh land reclamation programme was launched, initially by the Società Bonifiche Terre Ferraresi and, in the following century, with the additional and crucial contribution of the regional development agency, the Ente Delta Padano-Ente di Sviluppo. This exercise in land reclamation was a work of huge value from every point of view, and was carried out through the vital contribution of the land reclamation Consortium which has been operating in the area since the 17th century. Today this land, transformed into a vast and marvellous garden, is regarded as among the most fertile in the world.