The storm surge barrier near Ramspol was built to project the hinterland against flooding by high water form the IJsselmeer Lake. The barrier consists of three inflatable, nylon-reinforced rubber dams, each 80 meters long, 13 meters wide and with a design height of 8.35 meters. They are the largest dames of their kind ever built. The dam is inflated with air while a gravity-feed system allows water to flow in. The barrier is lowered again by pumping out the water and letting out the air.