Ice World Board for Mymeara Eldar WIP

I picked up the supplies tonight to start my new board.  I’ve been having an itch recently to build some terrain for a while now and decided to do something different and build an ice-world board.  It will go well with the Mymeara Eldar, but could be used for any army really.  The first picture shows my concept drawings.  The board will consist of 3 modular pieces (maybe expanded out with a fourth for variety later on) that can be put together in different ways.  The main feature is a large river that runs through the middle of the board that will be iced over.  I’ve marked where on the board the river banks need to line up so that they can be placed in any arrangement.  The other permanent feature will be some pipes that run out of the river from a pumping station.  The rest will be modular.  A few ideas that I would like to build: crystal forests, communications/sensor tower, islands for the river and outposts.  Also thinking a few Eldar specific bits like a webway portal.
After I finish cutting the foam up, I will paint with a light blue latex paint to seal the foam up, and then apply a fine sand to the foam portions to act as snow.  The real trick will be to do  the iced over river.  I figure I can paint it a dark blue and then use either a clear resin or water effects and than scratch the surface with sand paper to get an ice look, but I’m not sure yet.  Will have to experiment a little to figure something out.  If anyone knows a good tutorial on doing ice, especially in large scale post a comment.

Ice World Board Concept Sketch
Ice World Board WIP 1
Ice World Board WIP 2
Ice World Board WIP 3