Abstract: In order to provide a sustainable development strategy to ensure the long term survival of coastal and deltaic areas, the lagoon of Venice and the delta of Rotterdam were exanimated for possible alternatives. This article investigated the historical development of the city-water relationship in the two cities. The main focus was on the changes in the sedimentation-erosion relationship and their impact on the position and spatial structure of the city through different periods. It concluded by considering current and future possibilities for influencing the balance between deposition and erosion. In both cases three conclusions can be drawn. 1) Making better use of and responding to the natural tendencies and changes in the regional water system offers prospects for reducing the vulnerability of the urbanised landscape and for radically ameliorating the ecosystem. Crucial to achieving this is the restoration of a stable sediment-water balance. 2) This radical change can only occur in combination with a thorough restructuring of the port economy and shipping industry. 3) The history of the relation between city and water system reveals considerable variation in the way in which the natural system of lagoon, delta and estuary has played a role in urban culture and also been critical to withstanding problems like high water and saltwater intrusion. Greater concern for and attention to the historical evolution of the relation between city and river can play a crucial role in strengthening a collective awareness of the importance of a stable sediment-water balance for the urban landscape.