Questions About Water Source Environmental Demand Modifiers

Do the River Bank modifers apply to settlements built alongside streams and creeks, or only navigable rivers? Similarly, do the Lake Shore modifiers only apply to large lakes, or do they apply to smaller ponds? What about an oasis, perhaps one with a white palm?
If a settlement is built at the mouth of a river, does it get the Sea Coast/Lake Shore modifiers, the River Bank modifiers, or both? If both, do you add them together or apply only the most extreme one?
Is “None” an acceptable water source? If, for instance, the settlement relies solely on well water.

Do the River Bank modifers apply to settlements built alongside streams and creeks, or only navigable rivers?
APM: If the stream/creek is large enough to be the settlement’s main water source then it would qualify.
Similarly, do the Lake Shore modifiers only apply to large lakes, or do they apply to smaller ponds? What about an oasis, perhaps one with a white palm?
APM: As above. In the case of the Oasis of the White Palm, I’d call it a Lake Shore, yes.
If a settlement is built at the mouth of a river, does it get the Sea Coast/Lake Shore modifiers, the River Bank modifiers, or both? If both, do you add them together or apply only the most extreme one?
APM: It would get both.
Is “None” an acceptable water source? If, for instance, the settlement relies solely on well water.
APM: Yes. In this case you apply none of the modifiers.
Let me know if you have other questions! Keep in mind you can always “override” the Demand Modifiers if you need to, to achieve what you think feels right.

Thanks for the quick response!