Need an aquaduct?

[sumthinelse]

I have a settler next to a fresh water source, at least I think it's "next to" the fresh water source. 4 cases:

• One of the sides of the square is a river. No aquaduct will ever be needed.
  
• My settler's square is touching a square that has part of a fresh water lake in it, but not on a diagonal. It does not seem to matter whether my settler's square is actually touching the water; I will never need an aquaduct.
  
• My settler's square is touching a square that has a river in it diagonally. I believe that if the river does not run through the point where the squares are touching diagonally, I will need an aquaduct.
  
• My settler's square is touching a square that has part of a fresh water lake in it diagonally, but the water in the lake does not touch the point where the squares are touching diagonally. I believe that in this case, I will not need an aquaduct.
  

The manual does not define what "adjacent to fresh water" means, and lakes and rivers seem to behave differently, that is, with a lake, the city square does not have to actually touch the water.

This is kind of annoying when the river appears to be next to your city but they made the map so it doesn't quite touch, and 60 turns later you discover that that you need an aquaduct. IMO "river" or "fresh water lake" should be part of the terrain description when you right click.

 

[Qitai]

This is how I check.

Right click on terrian to see if it gets the commerce bonus, it is consider adjacent to a river.

If it is near a lake, it seems that diagonal always work, no excpetions yet for me.

And best way to check when there is no adjacent irrigation is to have a worker on the tile concern and if it can irrigate on that tile, it does not need a aquaduct.

 

[Lt. 'Killer' M.]

The river needs to be in a corner, but not if it is the corner where it comes out of a mountain, then you need an aqueduct!