Why can't my city build an aqueduct here?

[GrumboMumbo]

I want to build an aqueduct on the tile directly north west of my city (next to where I will place the IZ), I must be missing something, but I'm stumped...

 

[Ownsya]

I think you can't place it there because the aqueduct would be contacting the river on the same side that the river is already contacting your city's hex. The aqueduct should be able to go in between the city and the water source such that it's bringing water from somewhere that isn't already in contact with the city. If you look at the valid hex NE of your city center, the aqueduct contacts the river from the SE side of that hex which isn't in contact with your city, as an example. But where you want to place it, it would only be in contact with the river on the same side that is already reaching the city, so it wouldn't really be bringing water from anywhere new.

Edit: Hope that makes sense. Imagine putting down the aqueduct, it needs to go in between water source and city, somehow. That NW tile makes it impossible for the aqueduct to be "in between".

Edit2: Sorry for the spam but I think I finally found a clear way of explaining it: The side where the aqueduct connects to your city has to be different from the side where it connects to the water source. There

 

[GrumboMumbo]

No, that actually makes total sense. I didn't know that it worked that way. Thanks for clearing that up