I looked at some of them but I'm still stumbling with coast line outline and river combo. I did some trials with PS but it comes out a bit rough. The best stroke edge for a river that matches the coast outline was sponge brush but the color doesn't match. I also tried erase but they still come out pretty rough around the edges. Here is what I'm talking about:
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Name:	Trial 2.png 
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If you could point me in the right direction I would really appreciate it.