Location: Oregon Coast, USA! or Bohol, Philippines!
Posts: 16,064
Idea For Resource-Water
An example would be the midwest aquafer in the US. Without the water from underground there would be no breadbasket of the world. I suggest that underground fresh water seas become part of the Civ maps to be revealed upon achieving a certain sci, like other resources.
I think that water is already an implicit resource because you really can't do much in terms of growth without irrigation, unless its a special resource, so water is a requirement, either by ocean or river for practical growth.
Water as a resource like iron, I could see that in a desert city, but nationwide (all of your cities), I don't think its realistic.