Brants Gill Head system

[gus horsley]

Many moons ago, when our knowledge of karst hydrology was still a bit sketchy, it was assumed that Douk Gill was some sort of overflow for Brants Gill Head.  Has anyone come up with any new theories?  Or has anyone made any real progress in Douk Gill?  There used to be several digs in the dry valley leading up to Hull Pot and it's a long time since I was up there.

 

[Pitlamp]

I think access to that bit of land is an issue Gus.  But the ULSA Living Dead (etc) extensions to Penyghent Pot filled up quite a lot of the gap.

 

[Scoff]

Gus

The hydrology of Brants Gill/ Douk Gill ??? – an interesting question.

A good few years ago (late 80's) the underwater boulder choke in Brants Gill was examined in earnest by Biffo & I, and the water was found to flow up through gaps in the boulders. Such was the flow that pebbles dropped down fluttered in the current, hovered, then got blown back up & spat at the diver!

We theorised that the boulder choke restriction was sufficient to cause backing up behind it in high flow (flood) conditions. This would explain why, chronologically, Douk Gill starts to resurge next (being up dip) then finally Dub Cote (which is even further up dip) when even Douk Gill can't get rid of the volume of water either.

As Pitlamp prudently points out - access to Douk Gill is strictly forbidden (and anything else on the land nearby), which was a problem. Also the back end of Douk Gill was known to consist of an extremely low bedding plane which would require consdierable enlargement, and the cave floods suddenly and absolutely epically!!!

The next thing I considered was Dub Cote. The passages in the back end are long & generally small in cross section. However, I had been impressed by the size of the passages between sump one and sump five. There was one bedding spotted by Geoff Crossley years before which he had not been examined thoroughly at the time due to large amounts of silt. I persuaded Geoff that we should go & have a look at this, as I believed it could bring the flood water, when the fabled Master Cave (at least the Fountains Fell arm) backed up, into these large sections before flowing to its normal weather resurgence at Brackenbottom Risings, or  Dub Cote entrance itself as the flood resurgence. The large quantities of silt could be expected. As the flood receded, water flow would slow and sediment get dropped. After our first dive to the bedding, Brian Judd took over the exploration. He subsequently found a significant length of bedding passage heading towards Larch Tree Hole – though sadly it was very low and silty all the way, until it got too silly even for Juddy! I still believe that this is/ was a hydrological link to the Master Cave.

I can only suggest that you have many happy hours' armchair caving in front of you. Of particular use/ inmterest will be the CDG Northern Sump Index, the Bradford Pothole Club Bulletins (re: Brants Gill, Diuk Gill & Dub Cote), and the ULSA review with its riveting descriptions of the bottom end of Penyghent Pot, the surveys and excellent OS map with cave survey overlay.   

Hope this helps...

Scoff

BPC/ CDG

 

[graham]

Interesting stuff, Scoff 

All I can say is that if the passage was too silly for Judd then no-one else need apply.

 

[gus horsley]

Yes thanks Scoff.  Would it also be an accurate assumption that the various perched sumps in the area are also indicative of this backing-up effect or are they controlled by other features?  I can remember there was once a report of the sump in Hull Pot drying up and leading to a horrendous mass of boulders below the entrance chasm, but is the sump in Little Hull perched?

Also I'm amazed that there's still no access to Douk Gill - that was the situation at least 40 years ago.  But obviously there's been a bit of "unofficial" work going on the cave

 

[Pitlamp]

The portents aren't too good, for various reasons - but - if you were to go to Douk Gill in summer (please don't, to avoid creating even worse access problems!) you would be gobsmacked by the howling cold draught coming out of the western entrance (to the left of the main entrance).

Most people would agree that Douk Gill is probably a flood overflow for Brants Gill.  Whether Dub Cote is another (even higher) overflow for this same water is not quite as clear.  The best way to learn more would be to lob some dye in one of the main sinks and try and catch it on detectors at Dub Cote when contitions are extremely wet.  Timing of the dye injection would be crucial.

 

[Scoff]

Gus

There are some perched sumps in the area which have changed in the not too distant past. Without digging through various publications right now, I seem to remember the Hunt Pot Inlet in Penyghent Pot previously ended in a sump which then changed and more passage was found... I'm sure Pitlamp's encyclopaedic knowledge will kick in here  :bow:

Pitlamp

With regard to the water flow off the hill to Dub Cote/ Brackenbottom Risings, here's what I know...

(1) When the Old Guard were actively pushing Dub Cote in the mid-eighties, Alan Carr in Brackenbottom Hamlet (who was the landowner for Dub Cote) always used to comment on how his water turned brown whenever the divers had been in the cave. A pantomime style accusing stare was met with faces of perfect innocence from the divers.... And it was thought that the water flowing in Sump 2 in Dub Cote then went off in a roof rift to emerge at Brackenbottom Risings.

(2) A one-off water tracing test was done after the discovery by the BPC of Brackenbottom Pot or Giggel Rav (not that it matters as the latter feeds the former anyway). Optical Brightening Agent was used and unbleached cotton detectors placed in Brants Gill, Douk Gill and the bogs at Brackenbottom (!)

We got no positive results in the next few days at the former two sites, but we did find we'd got a positive result in the bogs at Brackenbottom a week later - not as strange as it sounds, as at that time the water supply was Brackenbottom risings (not mains water) I have a feeling that we always intended to repeat the test, but never got the materials/ opportunity...

Finally, with regard to the 'backing up theory' - look at satellite images of Penyghent/ Ingleborough and admire the huge fault that runs through Churn Milk Hole, the Big Shakehole near the wall below the shoulder of the hill, then Larch Tree Hole and finally Sulber Nick running up Ingleborough.

Now consider the 320/ 330 degree alignment of so many featured underground on Penyghent. Draw a line from Dub Cote entrance to Brants Gill. See how they just about line up.

If water came down the big fault (a line of weakness also perhaps exploited by the 'overflow' bedding in Dub Cote Sump 5) and then hit a 320/ 330 degree line to turn it to Brants etc. it all works when the dip of the limestone is taken into account.

Someday someone will hopefully prove the theory...

Still all good fun thinking and postulating, eh?

Scoff

 

[Pitlamp]

I'd agree with Scoff.  One day it'll all be understood.  (By the way - I think the Hunt Pot Inlet simply switched itself off in the mid 80s, so the sump (largely explored by the likes of Shackleton & Griffiths) became almost static instead of the powerful inlet it used to be.  Speaking of which I'm surprised that no-one has had a go recently at connecting it with Little Hull - they aren't that far apart.  Trouble is there's just so much to do . . . . .

 

[gus horsley]

If water came down the big fault (a line of weakness also perhaps exploited by the 'overflow' bedding in Dub Cote Sump 5) and then hit a 320/ 330 degree line to turn it to Brants etc. it all works when the dip of the limestone is taken into account.
Scoff

Maybe that's why Brants Gill is so bouldery.

 

[Pitlamp]

Maybe one reason it's so bouldery is because immediately beyond where the sump is there's that huge collapse depression on the surface?

 

[NigR]

...if you were to go to Douk Gill in summer (please don't, to avoid creating even worse access problems!) you would be gobsmacked by the howling cold draught coming out of the western entrance (to the left of the main entrance).

Draught sounds interesting - how far can you get in this western entrance and what happens at the end?

 

[Pitlamp]

Several tens of metres as I remember.  You end up in a very wide VERY low bedding, with deepish water.  Using one eyeball as a periscope doesn't reveal any obvious direction to push - and it's physically quite tight too.  I also remember a slightly drier option off to the right of this low, wide area - again it was too tight for me.

Anyway - haven't seen you since you emigrated to Wales many years ago.  How's tricks?  Have you learned to cook yet?!

 

[NigR]

Sounds like you need a very small tame amphibious caver to take down there with you. Haven't got one at the moment but will keep my eyes open. Draught definitely needs checking out if it's as strong as you say.

Life is good in Wales, lots of exciting digging going on as always. Still can't cook a can of beans without constant supervision tho'!

Where are you living these days?

 

[gus horsley]

Ah, it brings a tear to the eye and a lump to the throat to know I've managed to contribute to Cavers Reunited.

 

[Pitlamp]

Hello Nig - in the Dales.  How's that Sink Y Giedd that you emigrated to Wales to dig about 25 years ago?!

Sorry - back on topic - a lot of hard small neoprene clad pushers have been for a look at that draughting bedding in Douk, without success.  It really is pretty grim I'm afraid.

 

[NigR]

.... a lot of hard small neoprene clad pushers have been for a look at that draughting bedding in Douk, without success.  It really is pretty grim I'm afraid.

Maybe Gus will fancy having a go next time he is up that way?!

Regarding Sinc y Giedd, it remains one of the prime sites down here. We found a pitch into a parallel streamway, then pushed a tight bedding to a point where a strongly draughting tube indicated the main way on. To date, only one person has been through this tube, discovering a shattered chamber with several possible continuations. Not been down there for a while but the potential is tremendous. Got to watch the weather tho' - you would have a better chance of surviving in Mossdale in a flash flood.

 

[gus horsley]

.... a lot of hard small neoprene clad pushers have been for a look at that draughting bedding in Douk, without success.  It really is pretty grim I'm afraid.

Maybe Gus will fancy having a go next time he is up that way?!

You are joking aren't you?  The size I am nowadays I'd have trouble getting through Dim Dwr.