Water areas completed using a good gloss varnish, I use Ronseal Ultra Tough Hardglaze Gloss. This is a polyurethane varnish which is what you want, the water based gloss varnishes just don't dry shiny enough!
Here's a shot of the section I've been using to show the tecniques.
One of the tiles and a close up
To get some idea of scale first with 10mm Pendraken stuff, hopefully I've achieved the barren Falklands look?
Here's a shot with 20mm figures, a UKSF patrol calls a halt!