No, it is impossible to dig for water in the open desert on Arrakis during book one. The sand trout all capture whatever water is in the ground before anyone could possibly get to it. This works with the ecology of Arrakis, as water is poisonous to worms. The only place where one could dig for water would be in the polar caps. There are water merchants who siphon water from these caps. Other than that, the only place where water is found is in the atmosphere. Dew gatherers (men and women who harvest dew from plants) and windtraps attest to this.[Edit] Also, if you need any proofing done for the game, hit me up. Part of my job involves proofing, so I can probably spot any errors in the text.