In around 1875, the Ministry of War erected some 350 boundary posts along the length of the Kromme Rijn. The blue stone posts, marked with the letter O (for Oorlog, the Dutch word for war) and a number, marked the new route for transporting water to the New Dutch Waterline. The posts used to line up with plot boundaries. Many have been removed over the years, but the water board has returned 18 of them to their original location along the towpath between Werkhoven and Odijk following the construction of an environmentally friendly riverbank.
The Goejanverwelle lock and the Enkele Wiericke lock on the Hollandse Ijssel played a key role in the Disaster Year. Together with the lock at Nieuwerbrug on the Oude Rijn, they formed the inlet to the Langeweide polder, which was the narrowest section of the Waterline. The locks were opened on 17 June 1672 – just in time to halt the advance of the French, who had already captured Oudewater and marched right up to the edge of the hastily flooded Waterline. With great promptitude, the commander of the garrison at Goejanverwelle, the Count of Horn, gave the order to raise sconces and fortifications to defend the locks. For the moment, the Waterline was safe!