Mossdale Beck

[Pitlamp]

An artificial flood pulse was used by the YGS as early as 1879 to confirm a flood connection between Tarn Sinks and Malham Cove. The flood pulse took 85 minutes to reach Aire Head, but 130 minutes to emerge from the Cove which is less than half the distance. Presumable the delay in arrival at  Maham Cove is due to the water having to back up from the start of the phreas before being able spill over into a conduit which emerges at the base.

Which - though absolutely nothing to do with the original post! - suggests the presence of vadose cave above the eventually phreas which resurges at Aire Heads, with a connection to a higher level passage which leads through to the Cove Rising. Now, if memory serves, this upper passage is also fed from the Smelt Mill sinks (which water only emerges at the cove I think) suggesting this higher level passage is also vadose and flows downhill from its connection point which the main Tarn Sinks to Aire Heads route? An interesting test would be to set off a pair of flood pulses - the first to "fill" the cave, and then the second to test if there is still a delay in arrival at both the two risings - but I don't know how practical that might be! Just a thought 

Um - one problem is that the exact relationships between the sinks and risings still aren't fully known. The hydrology of the Malham area is very complicated and varies according to the prevailing weather and ground water levels. I'm not sure it's that useful an example for the purposes of this topic. Your suggestions (above) for the layout of the unknown system are interesting but there are various problems - the main one being that the hydrology of the area still needs properly sorting out.

In case it helps, here's an extract from something I've written for an (as yet) unpublished journal:

"The earliest water tracing experiments (over 100 years ago) revealed that sinks downstream of the Tarn (in the Watlowes valley) drained to Aire Head Springs to the south of Malham whilst water sinking near the smelt mill chimney on Malham Moor emerges at the Cove. As a result geography text books have often quoted the Malham area as a classic example of ?crossing underground streams?. This idea is probably an oversimplification of what is really happening.

The water from the Tarn sinks at various places along the Watlowes valley; the higher the flow the further the water goes down the valley before sinking. In the driest conditions the water has been tested to Aire Head Springs only. In slightly higher flow the stream uses other sinks a bit further downstream, under which conditions some of the water drains to the Cove base. As flow increases so an increasing proportion of the sinking water emerges from the Cove base, as the stream sinks ever further down the valley. In exceptional floods, where the stream flows over the dry waterfall at the head of the long straight section of the Watlowes, almost all of the water emerging from the base of the Cove is derived from sinks in the Watlowes valley. A large pool forms below this waterfall but the water goes no further in modern times. There may be a large buried entrance here; if this can eventually be found from below there is therefore hope of a dry way in.

The low flow route from Watlowes to Aire Head mentioned above is probably fairly recent and immature, so I don't have high hopes of a negotiable route for cavers. The role of the Smelt Mill sink is not really understood, since some tests have shown its water emerging both at the Cove base and at Aire Head Springs in varying proportions."

There's no doubt that air filled passages exist upstream of the underwater cave at the base of the Cove because large fragments of stream rounded flowstone have often been found by divers.

There are probably also air filled passages downstream of the main Watlowes to Cove drainage route as well, as the sinks in the Watlowes valley have been tested to Cawden Burst, a powerful flood rising next to the village of Malham. This only flows in extreme weather but it can produce enough water to flood the village. I can envisage a sort of Valley Entrance Roof Tunnel type passage behind Cawden Burst which is normally dry but carries a torrent in extreme conditions.

One thing is clear, there's many miles of passages waiting to be found in the Malham area; it's one of the Dales' last great problems.

 

[Chunks]

Back at Mossdale Beck, I have questions, questions, questions:

Back in the 60s/70s I have a vague memory that Mossdale Beck sank for a while some distance upstream of Mossdale Scar. Has anyone attempted to re-discover this old sink and was the water seen within the Caverns, possibly in the Far North? Is it possible that the water went not to MC but into the far reaches of Langcliffe Pot? Looking at Cavemaps, it seems possible that the latter was the case - there's even a line of miner's scratchings running in a line from the end of Langcliffe to the area near the shooting hut upstream of Mossdale.

I recall reading about that in an article in an old issue of the Speleologist. It goes something like: 1959, the sink was about 1/4 mile upstream of Mossdale and swallowed all the Mossdale water leaving the caverns largely dry. Apparently there's a fault between the sink and Mossdale and the sink is in a different bed of limestone.. Floods filled it in and it was never relocated (that was in an article ~1960s).
Always thought it sounded like an interesting spot and I've no idea if there's any other caves in that bed of limestone!

 

[andys]

Note to the Mods - Is it possible to copy this topic (or at least the relevent bits thereof) to a new Malham topic? It makes an interesting discussion in its own right but is way off the OPs subject!

 

[martinm]

Note to the Mods - Is it possible to copy this topic (or at least the relevent bits thereof) to a new Malham topic? It makes an interesting discussion in its own right but is way off the OPs subject!

Prob a fair bit of work for one of the mods, but yes I agree there's much valuable info in this thread, but as you say way off the OP... hmm...

 

[richardg]

How much cave passage is indicated by a two day flood pulse?

 

[Pitlamp]

Note to the Mods - Is it possible to copy this topic (or at least the relevent bits thereof) to a new Malham topic? It makes an interesting discussion in its own right but is way off the OPs subject!

You're right - it is largely off topic.

If anything just delete my posts about Malham etc above; they were only offhand remarks for general interest or to respond to points other folk had made. Anyone who was interested will have seen them by now anyway. Just scrap them rather than "mod" them. (I'd rather they got removed altogether than be manipulated by moderators.)

 

[richardg]

Its not off topic.....its all highly relevant...... Using adjacent models... To clarify the the dynamics and relevance of Flood pulses in predicting new cave.... And excellently presented .........

 

[martinm]

How much cave passage is indicated by a two day flood pulse?

depends on the size and nature of the intervening passage Richard. Redhurst Swallet to Wednesday Pot 300m distance 20  minutes, Ladyside Pot to Weag's Bridge Resurgence probably a similar distance (I'd have to check the map) 2 hours, but the passages involved are MUCH bigger, so slow down the flow of the dye and increase dilution of course... Goodness knows how a flood pulse would go through those passages, they are of such varying shape and there are sumps and lengths of open streamway too. It's very complicated as I'm sure the situation with Mossdale Beck/Caverns is.....

Oh, and John we don't want to lose your posts, they're very helpful and informative.

 

[Pitlamp]

Thanks for your vote of confidence Richardg - The trouble is moderators chop and change things round for what they believe are the best of reasons but often it inadvertently puts things out of context and can cause problems which they don't at first appreciate.

Don't get me wrong - I understand it's sometimes not easy being a moderator and overall I think they do a very good job. It's just that stuff I've written has occasionally had things done to it which detract from its value. On one occasion I politely raised this on the forum and several people jumped down my throat for daring to question the decision of a moderator and told me I was breaking forum rules.

I do a lot of proof reading of caving material and I put a lot of effort into consulting the originators of material I think needs changing before implementing such changes. My view is that the "rules" on here are unbalanced. The default should be that if anyone wants to alter an original poster's work, they should contact the poster first - it shouldn't be the poster who then has to chase up the moderator to complain. (Unless of course the post was unnecessarily defamatory - or there were other very good reasons for urgent action being needed.)

So - mods - please understand that this post is NOT a vote of no confidence. You do a good job - and one which I certainly appreciate. I guess I've just been waiting for an opportunity to get this off my chest for a while.

My request would be that if you do decide to intervene here - I'd prefer it if you just scrapped my stuff in this topic than start shifting some parts round.

There is only one editor I've come across who I would trust totally to get any text I'd produced right without my further involvement and that's Chris Howes. We are very lucky to have him as the editor of caving's flagship magazine.

 

[Badlad]

I would like to see this topic stay as it is.  Most of the posts are relevant to the OP and very interesting to those asking the question, even the author of the OP agrees.  Mossdale, Malham, Kingsdale, the topic is really about the hydrology, pulse, flow in cave systems. :hug:

 

[richardg]

Thank you for this information and your observations "langcliffe". Do you know who and where did the " two days" response time originate from?  is it based on factual quantitive data, was it an actual recorded observation or just heresay that perhaps somehow got written into caving literature and then becomes accepted fact?

The "two days" figure came from observations made by Rob Shackleton when he was diving in Black Keld in 1975. I don't have a reference, but it will be recorded in either the CDG Newsletters, or the CUCC publications, or both.

This evening I was chatting to a Caving Legend and he confirmed that the two day delay in the flood pulse arriving at Black Keld was indeed his personal observation and equally noteworthy is that this delayed response has been the regular pattern following each big downpour of rain.....

 

[Pitlamp]

Badlad - thanks for your thoughts above.

Hopefully on topic - there was a sudden and gigantic cloudburst over the Mossdale catchment on Sunday 20th July. I know this because I was involved in some work at Dove Caves near Park Rash (four days beforehand) and on the day after the Great Whernside weather event I was amazed by the signs of extreme flow which must have emerged from Dow Cave. I live on the west side of the Dales and we'd seen very little rain that Sunday but the devastation produced in the Mossdale area was apparently pretty awesome. A friend of mine has been gathering information about this (for possible use in an article - maybe in a future White Rose Newsletter). Does anyone have any observations on when the pulse emerged from Black Keld? I think the time that the flood hit Mossdale can be pinpointed pretty well, so we already have half of the equation.

Whilst I'm on about this (and, admittedly, not strictly on topic - sorry!) the catchment for the Dow Cave main stream is still not known. It struck me at the time that if we're ever lucky enough for a storm to happen in whatever is the Dow Cave catchment - but not elsewhere - it might help determine where the Dow Cave stream does come from. This is why I made notes of that flood at the time, in case it helped give clues about Dow Cave. As it turned out, the Great Whernside flood on 20th July was too widespread to be of use in determining the potential upstream from the Albert Hall choke in Dow Cave. But if we all keep our eyes open around that time of year in future, we might just learn some very useful information.

 

[richardg]

Badlad - thanks for your thoughts above.

Hopefully on topic - there was a sudden and gigantic cloudburst over the Mossdale catchment on Sunday 20th July. I know this because I was involved in some work at Dove Caves near Park Rash (four days beforehand) and on the day after the Great Whernside weather event I was amazed by the signs of extreme flow which must have emerged from Dow Cave. I live on the west side of the Dales and we'd seen very little rain that Sunday but the devastation produced in the Mossdale area was apparently pretty awesome. A friend of mine has been gathering information about this (for possible use in an article - maybe in a future White Rose Newsletter). Does anyone have any observations on when the pulse emerged from Black Keld? I think the time that the flood hit Mossdale can be pinpointed pretty well, so we already have half of the equation.

Whilst I'm on about this (and, admittedly, not strictly on topic - sorry!) the catchment for the Dow Cave main stream is still not known. It struck me at the time that if we're ever lucky enough for a storm to happen in whatever is the Dow Cave catchment - but not elsewhere - it might help determine where the Dow Cave stream does come from. This is why I made notes of that flood at the time, in case it helped give clues about Dow Cave. As it turned out, the Great Whernside flood on 20th July was too widespread to be of use in determining the potential upstream from the Albert Hall choke in Dow Cave. But if we all keep our eyes open around that time of year in future, we might just learn some very useful information.

Simon Beck and I were up at Dow Cave on this date the 20th of July and witnessed the Great Whernside Flood. It was an awesome phenomenon to behold! 

We parked up at the usual cavers spot at the foot of Park Rash, the weather was bright and warm and to be expected just a trickle of a stream flowed down the valley adjacent to the farmers hut and under the bridge. But what a sight and sound was the thundering big waves that characterized a river that came down the valley from the direction of Dow Cave..

It was obvious it was a special event, there was no sign of any rain or even a cloud in the sky, but here was river like never before.. we set off walking up the valley to find out more, all the time the thunder of the river echoed through the valley.

We reached the footbridge, again just a small stream flow under here, typical of the weather!  but the huge river continued to beckon us up to Dow.... there was no way to get to the Dow Cave entrance, it would have been suicidal to attempt to cross the newly formed river..It could only be viewed from high up on the left hand valleyside.... we took photos and videoed..... If anyone wants to make use of these for an article then let me know...

 

[richardg]

On visiting Fossil Pot whilst on an exploration project there recently we also observed flood waterflow evidence well above the height of the dry "big" 40 foot, as well as a couple of meteres up the sides of the chamber beyond the first  (pie muncher) squeeze when its usually just a trickle in the floor.

The evidence of the huge flood as well as in the Providence Pot surface stream ( mentioned in an earlier post on UK Caving) valley was very obvious along the fossil Pot valley where the usually dry valley had flood evidence of a river one to two metres deep and twenty foot wide at times, boulders had been shifted down valley, turf ripped off to reveal long hidden limestone pavement, and even large slabs of rock split apart with the force of water..

 

[martinm]

I'd be interested in seeing any photos / videos of that Richard. Must have a pretty big catchment area or maybe it was 'just' a very localised heavy downpour?

The Manifold and Hamps rivers have very large catchment areas and I have seen some spectacular flood pulses down both. No rain locally but up on top of Morridge Edge near Buxton presumably. Quite scary...

 

[richardg]

Hi Mel... Once I've relocated the memory card I'll get some of those pictures to you with pleasure.

As Pitlamp said it was a localized heavy downpour as you suggested, but also very reactive catchments.

Your description of spectacular flood pulses in the Manifold and Hamps River with no rain locally, and as our observations described above up in Wharfedale, Yorkshire are a reminder for explorers to remember a visual interpretation of localized weather isn't always a guarantee of no risk of flooding...

 

[richardg]

Hi Mel... Once I've relocated the memory card I'll get some of those pictures to you with pleasure.

As Pitlamp said it was a localized heavy downpour as you suggested, but also very reactive catchments.

Your description of spectacular flood pulses in the Manifold and Hamps River with no rain locally, and as our observations described above up in Wharfedale, Yorkshire are a reminder for explorers to remember a visual interpretation of localized weather isn't always a guarantee of no risk of flooding...

I would add to the above the need also to be aware of other not so obvious flood pulses

Such as in cave systems which are fed through water seeping gradually and slowly down through the rock stata, such as Sleetsgill Cave again in Wharfedale, where it can take a few days for the flood pulse to reach the cave

And of course Lathkill Head Cave and Dowell Resurgence  in Derbyshire

 

[bograt]

And of course Lathkill Head Cave and Dowell Resurgence  in Derbyshire

Been around Derbyshire for a loong time and never heard of flood pulses coming out from either of these locations, has anyone on here any experience of one? (Or, for that matter any other similar locations in the Peak?)

I have witnessed a very significant flood pulse being swallowed up by Redhurst Swallet, has anyone seen a corresponding pulse outlet from Ilam, or any other risings in the area?

 

[Pitlamp]

And of course Lathkill Head Cave and Dowell Resurgence  in Derbyshire

Been around Derbyshire for a loong time and never heard of flood pulses coming out from either of these locations, has anyone on here any experience of one? (Or, for that matter any other similar locations in the Peak?)

I have witnessed a very significant flood pulse being swallowed up by Redhurst Swallet, has anyone seen a corresponding pulse outlet from Ilam, or any other risings in the area?

That's definitely one for Mel to answer I reckon!

Whilst I'm on - Richardg, I just sent you a PM.

 

[martinm]

And of course Lathkill Head Cave and Dowell Resurgence  in Derbyshire

Been around Derbyshire for a loong time and never heard of flood pulses coming out from either of these locations, has anyone on here any experience of one? (Or, for that matter any other similar locations in the Peak?)

I have witnessed a very significant flood pulse being swallowed up by Redhurst Swallet, has anyone seen a corresponding pulse outlet from Ilam, or any other risings in the area?

Never seen any actual flood pulses from risings in the Manifold, only cos I've been watching the sinks further upstream being engulfed! For example Darfar Pot the terminal sump of which is 135ft below the river bed being filled to the top in 20 minutes! 

I've read the description of that terrible flooding event in Mossdale too, so I can well understand how quickly the cave must've flooded given it was largely horizontal. A terrible tragedy. You really do have to be careful with these places in unsettled weather... especially when the main catchment is a bit remote from the cave entrances... you often don't get any warning of an impending flood.

Oh, and in the Manifold area, it can take up to 12 hours after heavy rain on Morridge Edge to reach Wetton Mill, there are several large feeder streams which come down off the surrounding moors and flood before the main river does. That can give a small warning period. I guess it would be similar for Mossdale Beck depending on where the localised rain is falling...