The western part of the Netherlands had limited opportunities for inundation, so when the ’defensive line’ was constructed, there were additional defences constructed on the so called ’rechtervleugelwerk Spaarndam’ – this area had been previously reinforced with defensive batteries, and the new inundation points, constructed between 1882 and 1903, offered a new form of defence, allowing key strategic points to be quickly flooded in times of war, making the areas impassable on foot.