The southwestern sea clay area (Zeeland)
Creeks rose from the mud canals and salt marshes which developed in Zeeland’s peat islands. In Zeeland, these salt marshes are also called ‘schorren’. Clay was deposited on top of the peat layer during the flood tides, when the creeks flooded. Such deposits of clay are called water meadows.
Eventually the creeks silted up, and since the sand settled less than peat, the creek ridges were clearly higher than the water meadows in Zeeland. The water meadows and the creek ridges are together called ‘oldland’, because they make up the oldest scenery in Southwest-Holland. Later, the sea destroyed large parts of this oldland. The oldland has an irregular position and parcellation.
After the year 1250, Zeeland rised again by accretion. This land is called ‘newland’. The newland could develop in two different ways. The first starts with sand bars that gradually change into salt marshes. When the salt marshes lie high enough, dikes are built, resulting in more land. The other way is with an existing dike, which becomes higher through rising due to accretion.
The newland has, in contrast with the oldland, a regular parcellation and a flat position. The regular parcellation developed because more and more dikes were built, which safeguarded the pieces of land that rose by accretion. The reason for the irregular parcellation and the unequal positions of the oldland, is down to the settlement of the peat, through which the developed height varied hugely. Since the peat layer is lacking in newland, the difference in height is restricted and one might even describe it as flat.
Improved techniques made impoldering of the lower parts of the coast possible after the year 1600. Creeks and inlets were impoldered, allowing islands to be connected to each other. Additionally, the flooded oldland areas were diked once again.
The newland and the oldland do not only differ by parcellation and position. They also differ with regards to soil usage. The creek ridges in the oldland stand tall, and protect the land against the sea water. Moreover, the sandy clay of the creek ridge makes a solid ground for agriculture and fruit farming. For that reason, people would settle down on the creek ridges in the oldland. The surrounding water meadows are too wet for the cultivation of crops and are therefore mostly grass land. The sections where the creeks used to run can often be seen today: the creek ridges lie high up on the land and it is common for roads to follow the ways of the former or still existing creeks. The flat position of the newland enables versatile soil use, provided that the groundwater levels are controlled.