Climate adaptive urban planning and design with water in Dutch polders

The existing water management in Dutch polders is based on independent water systems for each polder. These are featuring artificial stabilized ground and surface water levels. As a result of the local climate the water levels in the polders are not continuously at a constant level. To maintain a stable water table in the polders, the surplus of relatively clean rainwater has to be pumped away during the cold seasons into canals or rivers, which are located on a higher level. During the summer relatively polluted water from these waterways is led into the polders to top up the declining water levels. This procedure leads to various problems regarding water quantity and water quality. The described existing system is not adaptable to climate change and includes the risk of flooding, particularly from torrential rain. Therefore it is crucial to develop, preferably self-sufficient, rainwater management systems in the polders. They should allow the fluctuation of the water levels inside the polders for seasonal storage and flood control. The described concept is adopted in the present water policy in the Netherlands as well as in research and recent urban development projects in Dutch polders.