The Grevelingendam between Goeree-Overflakkee and Schouwen-Duiveland was completed in 1965 . The Gravelingen south of Goeree-Overflakkee were still connected to the North Sea . The storm surge could therefore be higher here , so dykes were raised on the south side of the island in 1965 . Construction of the Brouwersdam was begun immediately after the Gavelingendam was completed in order to shorten the period of higher flood . After more than six years , in the spring of 1971 , the dam was finished . Between 1964 and 1971 there had been some very high water levels . In November 1966 the water was just a few centimeters below the level of the infamous floods of February 1 , 1953
floods of February 1 , 1953
North Sea flood of 1953
Brouwersdam