To avoid impacting the pore spaces even more, a wood deck installed up off the ground may be another suitable alternative. The feasibility of this idea would depend on whether there is enough fall from the door of the home to the ground where you are wanting to put the patio. Also, you would have to arrange your deck supports in a way that would avoid placing them in the leaching areas.
That's good advice.
Yes, keep the supports away from the field. I've seen wooden supports wick-up sewage up from below. It give the wood a very distinctive look!