Sarkamand

[Sapiento]

I added a light dirt texture to the buildings.

It's not uncommon that differently coloured rivers flow together. Here a quick Google search: 11 Incredible Points In The World Where Major Bodies Of Water Join Together

[Falconius]

Oh I know, I'm just saying that it doesn't seem to read that way to me. Perhaps because you are straddling that realistic/representational border with the rest of the map.
Edit: It could also be that colour difference isn't strong enough between the two rivers. In many of the examples the colour difference is Extreme.

As an aside, I think I preferred the map without textures on the buildings, in this copy they kind of blend more with the parchment texture and seem less substantial.

[Sapiento]

Oh I know, I'm just saying that it doesn't seem to read that way to me. Perhaps because you are straddling that realistic/representational border with the rest of the map.
Edit: It could also be that colour difference isn't strong enough between the two rivers. In many of the examples the colour difference is Extreme.

As an aside, I think I preferred the map without textures on the buildings, in this copy they kind of blend more with the parchment texture and seem less substantial.

I prefer the previous version without the texture, too. But I keep the current river colours.