dunes at the marker wadden, five sprawling artificial islands, constructed from sucked-up and refashioned fine silt, clay and

applying archipelago artificial biodiversity birding birdlife birds clay coast coastline constructing cultural dams delta development dike dikes dune dunes dutch ecological ecosystem environment flats freshwater heritage holland horizon islands lake land landscapes manmade marker markermeer marshes mud nature netherlands new opportunities reign restoration sand scenic sea shells shore silted sludge tides unprecedented valuable wadden water