Good job! I think the style for the rivers does go well with the style of the map (as far as the overall style can be determined from this zoomed in bit). The big, main river heading north does seem a little out of place, though. I don't know why, but it pops a bit much. This could be due to lack of stuff surrounding it, though (like trees, or towns/roads/etc.) I hope it's not rude for me to say all this. Overall, I think you're making great progress.