After two days of curing the forms were stripped and a water proofing membrane was added and covered with perfective panels of fiberglass.   I’m not worried about water, the ground is very pours, sand, loam, some clay and rocks.  So many rocks we will have to bring in backfill. Since the hole was opened we’ve had two different days of heavy rain (2″ +) with no acclamation on the floor of the hole.