This section of the survey shows the Grand Gallery conduit in profile.
The lines are at 25m intervals. The end of Potters is close to sump level though the unsurveyed chamber at the end rises above it.
Jills finishes up slightly higher and would pass under the Golgotha fault at a considerable distance below known cave if it gets that far. Both Potters and Jills have the potential to go beyond The Frozen Deep. Although not as messy as the Potters dig where it was horrible sticky mud Jill's is mucky wet gravelly stuff. Clearly that cannot be transported out through the entrance series so we shall use the paper decorator's oversuits we used during the Potter's dig. The washing area in lower Chain Chamber, now ineffective ,will be restored and used as well.
Originally phreatic water flowed through Grand Gallery to rise up Topless Aven and into the digs through to The Frozen Deep. As the phreatic levels lowered to the point where they are today at 26m Grand Gallery water drained down through Potters Heaven and Jills Slither to arrive at the main stream wherever it is today. There is still a stream in Grand Gallery on occasion though we do not know where it originates. A separate trickle joint this from The Silo. A small stream also runs under boulders in lower Chain Chamber to enter the Jill's area. In wet conditions water flows down from the Golgotha area and through part of Topless Aven to sink in the floor at the bottom of Grand Gallery. In flood conditions water backs up from the sump at Dingley Dell and makes the Potters dig impassable. There is evidence that in the past water backed up into lower Chain Chamber though I dont know if anyone has ever seen that. Both Potter's and Jill's digs have evidence of dryer spells with stalagmite false floor forming above the sediments.