Some side notes:
That is a pretty warped (and incorrect) map of the Netherlands. Most of the big waterworks are quite well (pun intended) indicated on that map though.
But there are so many more and those are missing. One very long canal in the south has been omitted. I lived near it at the time. It has many sluices/locks for the leveling of water between two big rivers (the Maas and the Rhine). There are more and more ancient water works. One of those enables the capital city from the southern province of Noord-Brabant to defend itself against (land-based) invaders. And it still works after 400 years. That was tested, because in my youth there was a period of heavy rainfall in the area where I lived, but also in the areas where the rivers Maas and Rhine sprung from.
My home was about 10 miles away from that capital city and lots of cattle had to be moved and crops were wasted as grass fields and crop fields were flooded by that water-based defense system from the capital. Quite some bridges became submerged, sluices in the canal had a lot of problems, the moat of a castle nearby my village rose significantly (resulted in 5 year long repairs at that castle)... After a day, the old pumps in and near the capital started their work again and pushed the excess out as fast as the downstream cities, sluices and harbors could manage. About 100 miles are between the province's capital and the North Sea, where the rivers Maas and Rhine end up. Took three to four days to get rid of all the excess.
Not much repairs needed on river dikes, bridges, sluices etc. though. Solid engineering and tax money efficiently at work. In the area where I lived, all the water-works are semi-state and they take their job seriously.
A good example of: "It ain't much, if it ain't Dutch."