How to Make Swamp/Marsh/Bayou/Delta next to a coastline

[wisemoon]

Hey everyone. I am working on a regional map, and the area is a very swampy peninsula. Think of it as a cross between Florida and Louisana (USA). When I look at Google Maps, the coastline of Florida around the Everglades, and the coastline of Lousiana near New Orleans, look very shredded to me (for lack of better terms). See these images for what I'm talking about:


I have created regional maps using Rob A's tutorial, and I've created an atlas-style map using Ascension's tutorial. I played around with Rob A's method of randomizing coastlines, which is mostly using blur, random noise filters, and Levels adjustment. It's a good method, and I was able to get something interesting, but it wasn't the same kind of shredded effect I am seeing on actual land maps in Google Maps.

I'm wondering if anyone else has any ideas on how to get this effect? It appears that on swampy coastlines, as opposed to rocky ones, there is a lot more creation of islands, sandbars, etc. so the land edges are not as clear as they would be with a rocky coastline.

Thanks in advance for any comments or suggestions. Also, as I keep working with the experiment I will post some images of what I've done.

--wisemoon