Polderisation is the reclaiming of land from the sea or in wet zones by building levees, filling and draining
This artificially created land (polders) can be used for agriculture, infrastructures (e.g. airports) or urbanisation, but polders are vulnerable to flooding.
An agricultural polder such as can be found in the Netherlands. Canals and mills can be seen continually draining the water from these wet zones. © Edward MacGregor CC by-nc-nd 3.0