The invention of technology for land reclamation in the 10th century started a unique transformation in the delta. Sand plates were dike-ed and pumped and became polders. Examples of early harbor cities created on the dike-ring are Ooltgensplaat and Oude Tonge. These cities were founded at the main creek of a sand plate. The polders created a condition for more sediment deposition, due to the hard edges of the dikes. Outside the dike-ring sediment cumulated and formed new sand plates. These sand plates formed the basis of a new adjacent polder and a new harbor settlement. The latest polders date from 1930's, but technically the process came to an end in 1953 with a stop of sediment transportation in the delta. The Watersnoodramp in 1953 led to the engineering of a great and expensive water defense project that would protect the inhabitants of the Southwest Delta against probable storm surges. Shortening the Dutch coast line and closing the Dutch Southwest Delta. However, the Delta Werken caused complications that were not predicted in time of planning and construction. The world known water defenses created environmental problems as blue algae in the Krammer Volkerak, lack of oxygen in the Grevelingenmeer, and the deciline of sand plates and fish migration in all the water bodies. [Programmabureau Zuidwestelijk Delta, 2009] Today, these problems triggered the discussion of re-opening the estuaries of the Dutch Southwest Delta. The graduation project provides research by design on the spatial implementation of the paradigm 'working with nature' in an open Dutch Southwest Delta. The open delta scenario, as proposed by H+N+S (Toekomstbeeld ZW Delta) and WNF (Met Open Armen), gradually restores the delta dynamics in the Krammer Volkerak. The process towards an open delta not only provides a form of the urban landscape. It also contains a new and innovative approach by integrally constituting value in the urban, cultural and natural layer. The new relation of delta cities with water, nature development combined with fresh water storage and day-recreation depict a scenario that sustains the dynamics of a natural delta landscape, social initiative and the improvement of the socio-economic condition of the delta cities Oude Tonge and Ooltgensplaat. A possible future of an open delta. PROGRAMMA BUREAU ZUIDWESTELIJKE DELTA (2009), Toekomstbeeld Zuidwestelijke Delta 2050. Retrieved 10 september 2011, from:http://www.zwdelta.nl/dyna misch/bibliotheek/70_0_NL_Toekomstbeeld_def1.pdf.