Delta Works
Delta Works, in the southwestern Netherlands, a giant flood-control project that closed off the Rhine, Meuse [Maas], and Schelde estuaries with dikes linking the islands of Walcheren, Noord-Beveland, Schouwen, Goeree, and Voorne and created what amounts to several freshwater lakes that are free of tides. Devised by the Dutch engineer Johan van Veen, the plan acquired great urgency after a catastrophic North Sea flood on February 1, 1953, which killed 1,836 people and devastated 2,070 square km (800 square miles) of land in the southwestern Netherlands. Construction of the Delta Works began shortly thereafter and was completed in 1986. The Delta Works is recognized as one of the Seven Wonders of the Modern World by the American Society of Civil Engineers.
A total of 13 dams, including four barrier and nine secondary dams, were built to close off the mouths and inner reaches of the broad, long, interconnected inlets that for centuries had exposed the region to the destructive power of the North Sea. The project shortened the region’s vulnerable coastline by 700 km (435 miles), thus dramatically reducing the length of the dikes exposed to the sea. When the dams were completed, fresh water from the Rhine and from other rivers gradually replaced the entrapped salt water. Total length of the dams is 18.5 miles (about 30 km).
The last barrier dam to be completed was the Oosterscheldedam, which stretches across the three channels of the Eastern Schelde, or Oosterschelde. This dam consists of several strings of gates and their massive supporting piers and totals about 2.8 km (1.75 miles) in length. It differs from its predecessors because it has adjustable gates that in normal weather allow tidal seawater to ebb and flow in the Oosterschelde estuary, thus benefiting the fish and bird life and the local fisheries. During a severe storm, however, of the type that caused the 1953 flood, the gates can be dropped to keep out high tides and storm surges and prevent them from inundating the adjacent lowlands.
New roadways and connecting bridges were built over several of the Delta Works’ dams and dikes, thus ending the historic isolation of the area from the rest of the Netherlands. From 1995 to 2015 numerous dikes were reinforced or replaced along the Westerschelde and Oosterschelde, and additional improvements, including higher and wider dikes, were planned in an attempt to combat sea-level rise as a result of anthropogenic climate change.