Maps of the planned Markerwaald polder in the Markermeer lake in the Netherlands. Originally planned by the Dutch civil engineer Cornelius Lely as part of the other polders in the Zuiderzee known as the Zuiderzee works, the first image is the original planned extent of the polder until the 1960s, the second image is the extent of the polder after revisions were made throughout the 1970s and early 80s due to environmental concerns (believing that the use of the Markermeer for recreation and as a buffer protecting Amsterdam from weather coming from the North Sea outweighed the potential benefits of the polder), and the third image is the Marker Waaden, a chain of islands that will instead be created in the lake after the original polder was scrapped.
Did the Dutch have any other land reclamation projects that never came to be IOTL?