|>>|| No. 20001
There's a reason no-one else does cloth boards like that. You can't add flock, grasses and gravels to something you fold up like a cloth, bending glued surfaces breaks the glue and it'll all fall off. You could do something like this pictured, using inks and dyes to draw a map - that could even end up looking quite cool if you did stylised it like a fantasy map, as seen in LoTR and Warcraft 2 loading screens.
That said, while the solid ground will come off right away, you absolutely can do some really nice looking water by using layers of liquid latex mixed with inks, although you'll need to find a way to seal it (a thin top layer or silicone perhaps?) or else it starts to gather dust and crap and look horribly yellowed in a matter of months. I'd start with an opaque base then build a number of blues on top of that. Experiment first obviously. A hair-dryer will help you dry the successive layers faster than the air. I'm not sure what technique would work best to make waves but I'm certain it can be done.