Thanks Duane, sounds like i should post a general question and hope that someone with more experiance than we have can give us some free advise.
We have read many books too and read here at pond boss but there were no exact situations, ponds seem to be like DNA or fingerprints ie no two are alike. Ours is a sort of soft sand soil so there doesnt seem to be much of what I have read as being a seal...almost seems like water moves up and down, there are springs down there...but this heat and dry weather have evaporated a lot of water.
Good luck to you on your project