Thinking of making a marsh?

Now that my rivers have been brought up to speed I can start thinking about making some marshes for the battle board. I decided to make my marshes big to cover a large area on the field, this is so troops will be forced to trudge through them rather than skirt around the edges.
I used my old favourite, Daz air drying clay to make the shallow contours of the swamp. Again this is all being made up as I go along, so I'm not sure what the end results will be. Well, something is better than nothing so watch this space for the results.
Here are the two marshes in their early stages.