River placement help

[Gidde]

The easiest way to make rivers in the right place is to start at a mountain range and go toward the ocean, getting curvier as you leave the highlands. Then once you have that main "trunk" you can start making smaller and smaller branches that leave it and go toward other parts of the mountains. Just make sure all your branches are on the mountain side, as rivers join as they go toward the ocean. Do that until you have sufficient drainage for the snowmelt coming off all the mountains and you'll look natural.

[darkfaterpg]

But where do the rivers start forming in that map? I don't have a clue about the areas that could contain enough water to start the flow of the river.