The entrance to Flood Entrance is about 80 m from Bar Pot on the other side of the path to Gaping Gill Main Shaft, in a small rocky shakehole into which a trickle of water sinks (see surface survey). A wriggle through boulders comes to a 4 m climb down into an enlargement above a narrow rift. Traversing at this level access can be gained to some bouldery avens which must be very close to the surface, The first and second pitches (cross section), the first (6 m) vertical, the second (10 m) broken and constricted - it was called the Agony or the Bottleneck by the original explorers - drop from this traverse level. Below the pitches is a short crawl, the Portcullis, and then a high straight rift into which the pitch from Wade's Entrance drops just before two right-angled corners (survey). A small stream flows into this passage and accompanies the caver for most of the route.
The next 65 m follow a fairly straight passage whose height varies from a comfortable 3 m to a hands and knees 1 m. Shortly, on the right, is a twisting low muddy inlet passage which closes down after 10 m. With a small sigh of relief one arrives at the double zig-zag in the main passage, with some nice solution holes in the roof. From here the way is high and easy, passing under two avens from which water falls, the first of which was connected with OBJ Hole by the BPC in 2009. The second aven is just beyond a little climb down into Cigarette Chamber, and can be climbed for about 15 m until it narrows.
Cigarette Chamber is simply an enlargement of the rift, which continues ahead (narrowing until passable only at floor level) into a little chamber filled with a mud pool. From here, 2 m up, a narrow inlet passage formed along right- angled cross joints finally narrows impassably. From Cigarette Chamber, the way on, and the route taken by the water (survey), is under the right hand bedding plane which extends over the whole of this area. In its floor a winding canyon, with a branch from the muddy pool mentioned, quickly cuts down to the head of an interesting and sometimes wet, 4 m climb. The bedding can be seen continuing over the top of the climb. Incidentally the twenty foot pitch which, according to Northern Caves Vol. 3 bypasses this climb, is non-existent, as can be verified by a careful inspection all the way round the bedding plane.
The climb lands in a pool, from which the water flows off left and down a steep shaft for 10 m to a little sump. It is possible to enter this sump for a leg length at which point a small rise in the roof can be felt. The water is seen again further down the main route, a few metres beyond this point.
To the right the dry bedding (which has the most extensive development of any shale bed in the pot, and is the same bedding as that which forms the roof of Bridge Hall in Bar Pot) shortly comes upon the head of a 14 m pitch - a pleasant, seldom wet, free hang. To the right the bottom of a 7 m high aven can be reached, and the water entering here flows down the pitch behind a sort of honeycomb wall. Scaling the aven only gives access to a 10 cm high bedding.
By traversing over the pitch a dry crawl is reached, containing a few formations, which shortly divides at a T-junction. Right is a winding low canyon in a wide bedding to a 10 m pitch. At the bottom a small stream enters from a tight hole in one wall, and flows off along a passage to a sump to reappear at the bottom of the 14 m pitch on the main route. Left at the T-junction, the crawl continues over a couple of narrow rifts down which water falls. It is possible to descend one of these rifts arid emerge at the bottom of the 10 m pitch just mentioned. Further crawling (upstream) reaches a junction, from where the left-hand branch, a wide low bedding with numerous straws, closes down in a short distance. The right-hand branch, by now rather muddy, continues in a very wide bedding until most of the water enters from the right. Following this, a tiny pool is reached, beyond which the immature inlet is too tight to follow.
Instead of bearing right, ahead a rift opens up in the roof and cou1d be followed standing up if a large block had not fallen and forced a detour via the low aqueous bedding on the right. (From this point it is possible to continue in the bedding for 15 m or so until it becomes too tight.) The rift, however, continues with varying height and tightness, and is in places nearly blocked by boulders. Eventually a shattered chamber is reached and a climb up the boulder slope reveals the way on, a crawl in a muddy low passage. There are several awkward squeezes round blocks, and then the end is reached - a total boulder choke. Under the left hand wall the base of a thin 10 m aven can be gained, but there is no way on.
Back on the main route, from the foot of the 14 m pitch two ways are possible. A climb up gains an inlet passage which leads to a neat little sump, the same one as is reached from the bottom of the 10 m parallel pitch. This has been baled to reach an silt-choked elbow a metre below the normal surface.
The other route, downstream, is a finely shaped rift passages with an interesting foot-trapping slot in the floor. Where this slot widens a pool has formed in the bedding below, and by turning upside down water can be seen entering the bedding from a tiny hole. This is the water that leaves the main route just below the 4m climb. In the left wall of the passage above the pool a small tube leads to a small blind pot.
Continuing downstream the passage keeps its shape then the bedding at floor level enlarges and a chamber is reached, from where the stream cuts down in a series of small cascades to the head of a 4 m climb, sometimes wet. A washed-out bedding can be seen continuing on overhead.
Straight ahead below the climb, instead of following the stream off to the right, a bouldery rift is reached which soon closes down to a tiny, muddy passages. This is Horrocks - Stearn Crawl which connects with Bar Pot above the 110ft pitch. The stream, however, runs into a crawl and drops into the chamber at the head of the last pitch, from where it reaches South-East Pot in a shower of spray. This chamber has a bedding en1argement all round, a ledge below on which it is possible to traverse (while lined!) over half-way round the shaft, and an aven in the roof which one would need an anti-gravity belt to reach.
The pitch of 38 m is a fine climb, which passes two shale bed enlargements which correspond with those on the Bar Pot pitch.
It lands on a wet ledge 3 m below the level of South-East Passage, which forms a shelf round the shaft. From here a tunnel in the wall, and a climb up slope, connect later and continues to Sand Caverns and Main Chamber. On the opposite side of the shaft another climb up boulders leads to a high rift passage, with a funnel-shaped hole in the floor which connects with South-East Pot. A climb over a dropped block emerges at the base of the big pitch in Bar Pot.
South-East Pot (also called Flood Pot), the continuation of the last pitch of Flood Entrance Pot, is in two parallel shafts in its upper section. The smaller may be descended as a pitch of 21 m. A sloping floor of rocks is gained, and the way on is under a lip, through a small hole and down a further pitch of 18 m. From the head of this pitch a tight bedding can be followed only a short distance. The descent drops straight into the sump with no place to rest. A small parallel shaft can be seen part way down.
The sump has been dived to a depth of 30 m, there being no obvious horizontal development. The floor of the sump is of fine silt, with no apparent further way on. The water in the sump has been dye-tested from the Main Chamber and from Stream Passage Pot, indicating that it is a window into the main phreatic route.
Some 15 metres below the main ledge at the top of the first pitch, there is a large hole the south-east wall. This can be entered by rigging from the scaffolded hole in the passage to the Bar Pot chamber. A 4 m high passage, named Robin's Rift, leads to the top of a 9 m pitch down into an echoing boulder-floored chamber - Lost River Chamber (survey). Above is an aven, from which issue some drips, but it appears to close down. Pitches at either end of the chamber lead back down to sump level, with the one to the south-east descending a rift which extends back under the false floor of the chamber above. This shaft has a small stream entering from the south-east end through a small fissure, which has been tested from the sink in Far South East Passage. The first sump has been plumbed to a depth of 25 m, and the second to a depth of 37 m.
From a rebelay in the south-east shaft, a steep treacherous mud slope can be surmounted to reach a chamber called Bill Spencer Chamber, which is at the same level as Lost River Chamber. This has an alternative hole down into the second shaft, but above a mud bank, a fine 5 m high rift passage continues for 15 m, leading to an immature tube with the water from Far South East Passage flowing through it. This ends in a substantial blockage after 10 m.
All these passages are formed in a huge rift, which begins at the top of the Flood Entrance main pitch, and extends to 37 m below sump level, giving a vertical development of at least 115 m - comparable to some of the deep phreatic features formed in the mineralised faults of the Castleton and Bradwell area of the Peak District.