In 1808, the French decided to protect Grado - evidently after experiencing what a strong sea storm could cause - with a reef of large stones taken from Istria, some 750 metres long. The remains of this cliff can be found in front of the present dam. After seven years of occupation, the French left the island of Grado in January 1814.
Actually, a kind of palisade driven into the clay was built as protection as early as 1750 on the authorisation of the Venetian Republic. The actual dam was instead built by the Austrians in 1885. Over the years it was transformed, lengthened and modified. In recent years it was enlarged with the insertion of some special scenic fountains.