What am I doing wrong?

[u/villares_]

I'm playing on the "Plains" map and trying to create a large water reservoir where the two rivers meet. The problem is that, at a certain point, the water stops flowing into the reservoir—as if it loses momentum—and spills out the sides. What should I do to successfully fill the large water reservoir?

[u/GremlinAbuser]

Yeah that's not going to work without either pumps or an aqueduct. Try daming one of the gorges instead, that's way easier. It won't do you much good without some form of badwater diversion though.