Bart Schultz
Peat polders, for example, typically have narrow parcels containing trenches separated by ditches and collector drains. Clay polders often have much larger parcels with subsurface drainage. There is often a clear difference between older clay polders with irregular parcelization and drained lakes with very regular parcellation. The period of reclamation can often be roughly determined from this parcellation, because the more recent the reclamation, the larger the parcels. For example, the parcels in the most recent drained lake, Southern Flevoland, typically measure 1,000 by 1,500 metres, with collector drains along the long sides and a submain drain along the short sides on one side and a road on the other. There are also river polders, usually clay polders, with a characteristic parcellation.
Especially in the later land reclamation projects, plot sizes were based not only on soil and water management but also on optimizing the costs of the land reclamation and subsequent agricultural exploitation. In the last century, agriculture saw a dramatic increase in scale, which is still ongoing. For example, in the Wieringermeer Polder, land was leased to farmers in units of 10 or 20 hectares. In Southern Flevoland, the units were 40 or 50 hectares.
In the older clay polders, the plots do not always have the same width. Originally, their dimensions were determined by drainage through open drains. Since the mid-19th century, subsurface drainage has been increasingly used, with several open drains being filled in at that time.
The original parcellation in the polders often remained unchanged for years. This changed particularly after the Second World War. This was partly due to the large-scale land consolidation that took place in the rural areas of the Netherlands. It was also caused by the massive urbanization that took place in many polders. In some cases, however, elements or components of the original rural parcellation can still be recognized in the urban pattern.
In the near future, the Netherlands aims to build one million houses with the associated infrastructure and amenities. Roughly 70% of these houses are planned for the polders. This will naturally lead to the disappearance of a significant portion of the original housing developments, and will result in significant changes in water management. These changes are caused, on the one hand, by the requirements that water management in new housing areas must meet, by the accelerated discharge from new housing areas in the polders, and by the influence of climate change on extreme rainfall.
It will be primarily the responsibility of the Water Authorities to ensure that the adjustments, which are usually implemented locally at the request of the municipalities, properly consider the importance of sound water management under the changing circumstances. Time will tell whether this will indeed be the case.
