About adding the slope of the river

In the renewal of l.18, the mountain range has increased its height, but the river originating from the mountain range has not obtained the height similar to the mountain, but maintained the same height as the sea level.It's strange. I think the river should have its source and slope instead of being so single and flat.

l suggest improving the river creation mechanism. The source and slope can be added to the river. In order to improve the generating possibility of large rivers, l also suggest widening the Estuary.Add a connecting channel between the surface runoff and the subterranean stream to increase the player's interest of exploration.Adding these features of rivers can increase the playability make the terrain of Minecraft look more magnificent and natural.