You will have better gold recovery when using water, but the trade-off is the weight, and being able to bring enough to make it worthwhile.
I would suggest a 2-3 interconnected large tub system. Set your sluice in the first and use the other 2 as "settling ponds". Set your pump in the last.
The problem is it won't take long for your water to turn into thin to thick chocolate, not good on pumps. Only cure is to change out to fresh water.
Depending on tub sizes and the other variables, you could go through a couple hundred gallons in a day, or more.