when applying the water body of the river on a curved surface, as well as when changing the height and turning near the river, an empty crack appears between the water of the river and the land
Perhaps your shader has been modified to add opacity with Distance to Nearest Surface?
If that isn’t the case, try to replicate this in a new project and provide steps for replication…
I apologize for my English, as I am not very proficient in it. It will be quite difficult to translate your message accurately, but I’ll do my best to convey the meaning. From what I understood, you mentioned a project involving a map and various elements. You mentioned that when you tried to do it on a flat surface, it seemed fine. However, when you used a real-world terrain displacement map and made some adjustments, the parameters might not have been proportional, resulting in a landscape with square bumps that you later smoothed out with tools. Could this be the reason? And you also mentioned that after adding rivers using a water plugin, a certain issue occurs over time.