BCRA Booklet 'The Hydrology of Goyden and Manchester Hole'

Goydenman

Well-known member
I read with interest in Descent about the publication of a new booklet entitled 'The Hydrology of Goyden Pot and Manchester Hole'. Having downloaded it from http:tinyurl.com/bvhdzu8 I read it right through in detail. It is a really useful booklet for people and on the whole ties very well with my own experience (22 years experience, some would say an obsession with the Goyden system) and knowledge I have of  the hydrology of Goyden and Manchester. I think the booklet is good and would recommend this booklet for anyone thinking of leading a trip into these caves and add my own following comments.
  • Graham Mollard has done a good job producing the document and says 'reflects my personal views and experience'. I think it would have added a bit more value if he had consulted those with a lot of experience in the Black Sheep Caving club but that is my own personal view. It does mean however I now feel compelled to add my own views which I think makes for a messy process and potentially confusing for those trying to get a clear picture of the hydrology in these two caves because all the information is not in one place/document.
  • He states in relation to Goyden Pot and Manchester Hole that the 'One fact cannot be questioned - both fill to the roof in extreme conditions'. Black Sheep cavers have noted fresh flood debris in the roof of Goyden main chamber as well as water spurting out of Limley and Zannusi pots (the latter has been sealed) confirming the system fills to the roof throughout. The same is not true in Manchester Hole though. We have confirmed flooding in the lower section beyond ?the grovel? by Fossil Passage. But having placed markers in the roof of the main stream passage we got fed up of seeing them there years later and removed them. We never observed any markers moved or removed by flood water. We also have entered the cave when the water has been lapping into the entrance (the highest levels we have experienced) and still the water in the main stream passage was low. I suggest the large amount of mud and flood debris in the roof of the main stream passage has been used to make the assumption the system regularly floods to the roof throughout when in fact the debris probably dates from before the construction of the reservoir. I do though emphasise the lower section of the cave from ?the grovel? onwards can and does flood to the roof and that this can be alarmingly fast. We once entered Manchester Hole (long before the incident on November 2005) when Goyden was not full to find the grovel impassable due to high water level. We also experienced a fast rise in the level of the duck when digging Swinton Bypass.
  • He states 'there is possibility of a flood pulse in Manchester Hole when the upstream sinks are not saturated. However once saturation point is reached any possible rise in the water level from that source is negligible'. Our experience is that typically the saturation of the sinks is quickly reached and as a result water levels in Manchester are only slightly higher and still low. The important exception to this is when people have attempted to dig out the sinks (why they would want to do this beats me!) or the floods have opened the sinks. In both cases we noted the river level in Manchester Hole had gone from ankle deep to calf deep with knee deep fast flowing high water beyond the grovel and the end sumped to a high level completely obscuring what was the duck.
  • Mr Mollard lists the criteria for planning a trip prior to November 14th 2005 into Manchester Hole I think he missed out one criteria. Leaders need to assess is it safe to cross the surface river in order to get to Manchester Hole entrance and given other conditions (weather/run off/dam/wind direction etc) is it likely to be safe to cross when they have completed the trip. Even following the November 2005 incident it is still a good criteria to use. IE If it is unsafe to cross the river on the surface because the water is too high then it is recommended not to take a trip into Manchester Hole. If it is safe to cross then a trip into the Hole through to far side of the mudbank/?the grovel? is ok but to go beyond ?the grovel? other factors would need to be taken into account such as water level at the dam and in the cave, how much water is in Goyden, weather conditions including wind direction and strength and state of the sinks
  • As for his list of criteria for planning a trip prior to November 14th 2005 into Goyden Pot I think he missed one out too from this list. Worth walking up and down between Goyden Pot and Manchester Hole to check if any new hole have opened up especially following a significant flood in the valley. To our knowledge over the last 20 years four different holes have opened up and some of them more than once. Each had a significant effect on the flooding within Manchester and Goyden. The two most dramatic included a hole that opened up that resulted in water entering the Mud slope of Manchester Hole causing a major collapse of that bank. It blocked the lower stream route completely, water pooled up and flowed over the top along the base of the slope until it was cleared. The second one is the opening and closing of the ?fresh sink? by Goyden main entrance. This sink resulted in a large volume of water and flood debris blocking Eternal Optimist and causing a fast and major back up of water into Manchester Hole. A key factor that led to the tragic incident of November 2005.
  • This ?fresh sink? that opened up in January 2005 was also re-blocked by further flooding and again re-opened yet again by floods after that. Mr Mollard states ?this appeared to have been enlarged by persons unknown? and again states ?the sink appears to have been re-opened by diggers?.  Note: This hole has never been enlarged by diggers or re-opened by diggers. We know this because years prior to Januray 2005 Black Sheep cavers explored a hole (to the right and higher up by the cliff face) that took water in extreme flooding. Only the thinnest members could get in but it revealed a cavity within the boulders. Seeing as it was boulders from breakdown of the cliff and not cave passage we had no further interest. Years later in January 2005 flooding opened not only a way into this cavity but through into Eternal Optimist taking with it debris that blocked the passage. This was reported by us in Descent 183. The cavity was of the same size and has never been enlarged by us or anyone else. In that report it was also stated we planned to use this hole to gain easier access to the blocked connection in order to dig it out before attempting to seal the hole. The passage was only partially cleared by November 2005. Following the incident in November 2005 I was keen this ?fresh sink? is blocked to prevent further large amounts of water and debris to enter. So we dug out some of the rocks in the opening to get through to the cavity so a dam could be built inside close to where it enters the Eternal Optimist. After the first attempt the water found a way around to the right. Our second attempt seems to be working and allows some water through which has washed out the Eternal Optimist passage but so far holds back any debris.  As I said before unfortunately no guarantee can be given that this will stop all future floods entering here and again blocking the passage.
  • Mr Mollard states ?Is water flowing freely between Manchester Hole and Goyden Pot underground? This can be checked by the leader descending Bax Pot to ensure there is no ponding at Manchester Hole downstream sump.? This is a really good point and rarely mentioned. We once went down Bax Pot when Goyden was flooding but not full. Divers chamber was a lake with the surface of the lake almost at the height where Swinton Bypass enters
A really useful booklet and easy to download. But I do think these points are worth adding.
Chris Fox, (Goydenman)
 

graham

New member
Chris

I think it would be a good idea if you passed these comments back to Graham Mollard, if you have not already done so.
 

Goydenman

Well-known member
Graham good point - I have searched the internet for contact details but as yet found none. Does anyone have a contact for him?
 

Goydenman

Well-known member
langcliffe said:
Just for clarification, it's published by the British Caving Association, rather than the BCRA.
Indeed it is. Descent and now me got that wrong  :spank:
Graham and Peter K thanks for the contact details - I have sent it to the one given by Graham.
 

damian

Active member
Goydenman said:
I have sent it to the one given by Graham.
Don't know what address Graham has given you, but the correct one is the one on the BCA link given above. The address changed when he moved house a while back.
 
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