Mossdale Beck
- Thread starter richardg
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langcliffe
Well-known member
richardg said:
About two days, apparently, but it is complicated by the fact that Black Keld has a number of feeders. The Myers dye test in 1950 indicated 18 days for water to travel between the Syphon Passage downstream sump and Black Keld, implying that much of the intervening passage lies within the phreatic zone.
langcliffe
Well-known member
richardg said:
I'm not convinced. A flood pulse travels through a phreatic section at the speed of sound, as only the pulse has to travel. But in long canals the flood pulse travels at the same speed as the water flow, which is relatively slowly. A crude model based on the above figures indicates that 80% of the subterranean route between Mossdale and Black Keld lies within the phreas.
richardg
Active member
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?
langcliffe
Well-known member
richardg said:
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.
Pitlamp
Well-known member
I've just looked this up for you in CDG literature. The period when Rob Shackleton logged dives in Black Keld (along with his other regular diving companion on several occasions) was between 5th July 1975 and 16th January 1977. These are recorded in CDG Newsletters from No.37 (October 1975 issue) to No.45 (October 1977). I glanced through these quite detailed dive logs but they mainly describe lines and passages in the cave rather than general hydrological details. I also checked the CDG Northern Sump Index 1981 but again this doesn't give the details which you want to find out. There is no more recorded activity in CDG Newsletters until a different generation began work in the late 80s.
However, the CUCC Journals are available online - so now you know the period when Rob was active in Black Keld, you can have a look at CUCC publications yourself. They're extremely good; beware of getting sidetracked by also reading the many other interesting articles you'll find in there!
The other obvious source of information is ULSA Journals of course. Separately, ULSA Explorations Journal II (Ed. Paul Monico, Aug.1989) has a big section on the system behind Black Keld (pages 1 - 30, including a useful reference list) - you may pick up valuable information from that.
If you want to read the details of Jack Myers' hydrological work they're in Trans.CRG 1 (4) (Dec.1950).
However, the CUCC Journals are available online - so now you know the period when Rob was active in Black Keld, you can have a look at CUCC publications yourself. They're extremely good; beware of getting sidetracked by also reading the many other interesting articles you'll find in there!
The other obvious source of information is ULSA Journals of course. Separately, ULSA Explorations Journal II (Ed. Paul Monico, Aug.1989) has a big section on the system behind Black Keld (pages 1 - 30, including a useful reference list) - you may pick up valuable information from that.
If you want to read the details of Jack Myers' hydrological work they're in Trans.CRG 1 (4) (Dec.1950).
richardg
Active member
Thank you "Pitlamp".I'm really gratefull for all that informasion youve highlighted there.
The CUCC journal is indeed full of good enjoyable reading.... Rod has written a really good account of Black Keld.
Rob makes mention of a two day flood pulse response plus loads of other observations, however it is not necessarily the Mossdale Beck that's responsable for such a dramatic delaid response,
Though again, in the article it isn't stated if its Robs own observation of a two day response time or from what had been an assumption of fact....
The CUCC journal is indeed full of good enjoyable reading.... Rod has written a really good account of Black Keld.
Rob makes mention of a two day flood pulse response plus loads of other observations, however it is not necessarily the Mossdale Beck that's responsable for such a dramatic delaid response,
Though again, in the article it isn't stated if its Robs own observation of a two day response time or from what had been an assumption of fact....
TheBitterEnd
Well-known member
langcliffe said:
Sorry, don't want to drag this off topic but I am really not convinced it's the speed of sound which is 340m/s or IIRC about 8000m/s depending on which medium (air or water). Perhaps if this needs debating we should start another topic.
langcliffe
Well-known member
TheBitterEnd said:
You may well be right - I'm not a hydrologist, and hence in no position to debate it. My source was "Karst Hydrogeology and Geomorphology" by Derek Ford and Paul D. Williams published by Wiley in 2007. In section 6.10.4 it says:
"A floodwave (discharge pulse) will travel as a kinematic wave down an open vadose passage, and as a pressure pulse through a phreatic conduit. Large kinematic waves travel faster than smaller ones; both travel more quickly than the water itself, especially though pools. Transmission of a pressure pulse through a phreatic tube is almost instantaneous (at the speed of sound)."
TheBitterEnd
Well-known member
Thanks for that I understand now. Essentially it would seem to be saying that if you inject dye into a pipe you will be able to detect the wave front at the speed of sound (i.e. water will flow out of the other end of the pipe l/v) later but obviously the dye takes longer to travel through.
Despite having no competence to challenge Ford & Williams I think practical geology has adopted theoretical physics. A phreatic tube would have to be inelastic, perfectly straight, frictionless and a uniform x section (possibly circular?) and in respect of vadose passage then "tsunami physics" would apply ? - very fast in deep open open water with a very small amplitude and way slower in costal waters with a massive increase in amplitude but I don't think the mathematical model of the deep ocean would relate to any vadose passage in the world.langcliffe said:
I'm not denying the power and speed of a pressure pulse - 2 years ago the water main supplying Bentham from Settle burst and I watched Yorkshire Water taking over 15 minutes to close a valve to prevent creating a pulse back down the main to (I think) Skipton - a negative flood pulse.
langcliffe
Well-known member
peterk said:
In the context in which I was writing, I did not feel it necessary to include the supporting material and references supplied by Derek Ford and Paul Williams, but they are obviously worth reading and worthy of consideration.
richardg
Active member
If anyone is seeking a bit more information and the relevance of flood pulse / artificial flood wave data analysis then I'd draw your attention to ......
"The Analysis of flow data from Karst drainage systems.. Transactions.. Cave Research Group of Great Britain volume 7 pages 161 - 203.... This is referenced in much international speleological literature, and was written by Ken Ashton who I believe was a member of the NPC.
Also very interesting is an account of Ken Ashton's life... available on the net NZMS newsletter 66. The guy was amazingly intelligent and led an interesting life.
Now back to Mossdale Beck ??
"The Analysis of flow data from Karst drainage systems.. Transactions.. Cave Research Group of Great Britain volume 7 pages 161 - 203.... This is referenced in much international speleological literature, and was written by Ken Ashton who I believe was a member of the NPC.
Also very interesting is an account of Ken Ashton's life... available on the net NZMS newsletter 66. The guy was amazingly intelligent and led an interesting life.
Now back to Mossdale Beck ??
Pitlamp
Well-known member
(I apologise to the many experienced cavers here who will be only too familiar with what follows but I thought it may be useful to give a very basic summary of Ken Ashton's flood pulse work, for those who haven't come across these ideas.)
What actually matters to potholers is that a sump can be thought of as a U tube. Pour water in one end and it's displaced from the other end almost immediately. It doesn't really matter how long the sump is (for practical purposes) so, for example, a sudden rise in water level in the west Kingsdale Master Cave (during a summer storm) will result in a sudden increase in flow from Keld Head, even though the intervening sump is over a mile long.
However, the movement of a flood wave along a vadose streamway will be considerably slower. (A useful analogy here is that anyone who has watched the Kingsdale bore, or the Ease Gill bore, will know that these pulses travel down their respective becks at something like walking pace; it's a similar effect underground - but with a roof on.)
These two situations are extremes; the reality is often complicated by pitches, canals, etc - but knowledge of this situation has very practical uses for cavers trying to establish what a cave system is like between a sink and a rising. (By this I mean the last place the water is seen and where it reappears - either or both could be underground of course.) For example:
1. A flood pulse hits a sink and the resurgence flows faster almost immediately = you're unlikely to find much dry passage on the direct flow route - although of course divers may encounter high level passages which are dry).
2. A flood pulse hits a sink and there's a delay of many hours before the resurgence responds = a good likelihood of a long (non submerged) streamway being found in between.
3. An area has three sinks and two risings; damming and releasing each stream separately and watching the risings for flood pulses can determine the underground drainage routes without the use of chemical tracers - and tell you a lot about the nature of the cave systems likely to exist in between.
etc,
Here's an often quoted example of where observations as above were made, leading to predictions about the nature of the underground flow, which were subsequently proved pretty much right by direct exploration. If dye is placed into Fell Beck, sinking into GG, it takes many days to arrive at the resurgence (Clapham Beck Head) in dry weather. However, when there's a summer storm and a flood pulse hurls itself down GG Main Shaft, Clapham Beck Head responds sometimes in less than 30 minutes. Both these observations led to the idea that much of the intervening passage is submerged. Apart from the now vadose sections of streamway in Ingleborough Cave, this has largely proved to be the case.
From memory, Ken Ashton's classic work is in Cave Research Group Newsletters (along with many other fascinating articles of course!).
What actually matters to potholers is that a sump can be thought of as a U tube. Pour water in one end and it's displaced from the other end almost immediately. It doesn't really matter how long the sump is (for practical purposes) so, for example, a sudden rise in water level in the west Kingsdale Master Cave (during a summer storm) will result in a sudden increase in flow from Keld Head, even though the intervening sump is over a mile long.
However, the movement of a flood wave along a vadose streamway will be considerably slower. (A useful analogy here is that anyone who has watched the Kingsdale bore, or the Ease Gill bore, will know that these pulses travel down their respective becks at something like walking pace; it's a similar effect underground - but with a roof on.)
These two situations are extremes; the reality is often complicated by pitches, canals, etc - but knowledge of this situation has very practical uses for cavers trying to establish what a cave system is like between a sink and a rising. (By this I mean the last place the water is seen and where it reappears - either or both could be underground of course.) For example:
1. A flood pulse hits a sink and the resurgence flows faster almost immediately = you're unlikely to find much dry passage on the direct flow route - although of course divers may encounter high level passages which are dry).
2. A flood pulse hits a sink and there's a delay of many hours before the resurgence responds = a good likelihood of a long (non submerged) streamway being found in between.
3. An area has three sinks and two risings; damming and releasing each stream separately and watching the risings for flood pulses can determine the underground drainage routes without the use of chemical tracers - and tell you a lot about the nature of the cave systems likely to exist in between.
etc,
Here's an often quoted example of where observations as above were made, leading to predictions about the nature of the underground flow, which were subsequently proved pretty much right by direct exploration. If dye is placed into Fell Beck, sinking into GG, it takes many days to arrive at the resurgence (Clapham Beck Head) in dry weather. However, when there's a summer storm and a flood pulse hurls itself down GG Main Shaft, Clapham Beck Head responds sometimes in less than 30 minutes. Both these observations led to the idea that much of the intervening passage is submerged. Apart from the now vadose sections of streamway in Ingleborough Cave, this has largely proved to be the case.
From memory, Ken Ashton's classic work is in Cave Research Group Newsletters (along with many other fascinating articles of course!).
