Battle of The Netherlands - Background - Dutch Defensive Strategy - Structural Elements

Structural Elements

In the 17th century, the Dutch Republic had devised an effective defensive system called The Dutch Water Line, which could protect all major cities in the west by flooding part of the countryside. In the early 19th century this line was shifted somewhat to the east, beyond Utrecht, and later modernised with fortresses. This new position was called the New Holland Water Line. The line was reinforced with new pillboxes in 1940 as the fortifications were outdated. The line was located at the extreme eastern edge of the area lying below sea level. This allowed the ground before the fortifications to be easily inundated with a few feet of water, too shallow for boats, but deep enough to turn the soil into an impassable quagmire. The area west of the New Holland Water Line was called Fortress Holland (Dutch: Vesting Holland; German: Festung Holland), the eastern flank of which was also covered by Lake IJssel and the southern flank protected by the lower course of three broad parallel rivers: two effluents of the Rhine, and the Meuse (or Maas). It functioned as a National Redoubt, which was expected to hold out a prolonged period of time, in the most optimistic predictions as much as three months without any allied assistance, even though the size of the attacking German force was strongly overestimated. Before the war the intention was to fall back to this position almost immediately, after a concentration phase (the so-called Case Blue) in the Gelderse Vallei, inspired by the hope that Germany would only travel through the southern provinces on its way to Belgium and leave Holland proper untouched. In 1939 it was understood such an attitude posed an invitation to invasion and made it impossible to negotiate with the Entente about a common defence. Proposals by German diplomats that the Dutch government would secretly assent to an advance into the country were rejected.

From September 1939 a more easterly Main Defence Line (MDL) was constructed. This second main defensive position had a northern part formed by the Grebbelinie (Grebbe line), located at the foothills of the Utrecht Hill Ridge, an Ice Age moraine between Lake IJssel and the Lower Rhine. It was dug on instigation of the commander of the Field Army Lieutenant-General Jan Joseph Godfried baron van Voorst tot Voorst. This line was extended by a southern part: the Peel-Raamstelling (Peel-Raam Position), located between the river Maas and the Belgian border along the Peel Marshes and the Raam rivulet, as ordered by the Dutch Commander in Chief, General Izaak H. Reijnders. In the south the intention was to delay the Germans as much as possible to cover a French advance. Fourth and Second Army Corps were positioned at the Grebbe Line; Third Army Corps were stationed at the Peel-Raam Position with the Light Division behind it to cover its southern flank. Brigade A and B were positioned between the Lower Rhine and the Maas. First Army Corps was a strategic reserve in the Fortress Holland, the southern perimeter of which was manned by another ten battalions and the eastern by six battalions. All these lines were reinforced by pillboxes.