A 9-Kilometer Long Dam in the Netherlands

In the Netherlands, there's a 9-kilometer dam with 62 gates that are kept open year-round. Initially, they were building a concrete dam that would completely block the entrance. However, the tidal flats inside began to die off. Fishermen protested by sailing their boats out, and eventually, they halted the construction of the dam. The solution they came up with was gates that are normally open and only close during storm surges. Although it cost significantly more than a complete blockage, both the tidal flats and the oyster farms survived.