Bearded dragon Exo Terra Tank water dish question?!?!?

Nice tank! What I would do is go to home depot or lowes and get a few ceramic tiles. The larger the better. Then put those under and around the water dish. The bearded dragon will have to go over the tiles in order to get to the water and hopefully most of the sand will end up on the tiles and not in the dish. He may also like to bask on the tiles as they will warm up fast.