Elsewhere this week on the Ukcaving forum under another topic Grahams, Pitlamp and Langcliffe were discussing resurgences along the River Wharfe that may drain the so far unexplored mighty cave systems of Great WhernsideWe are investigating where the river tumbles over the dramatic Litton Falls, through a series of impressive deep limestone pothole type plunge pools near the town of Grassington.A question..... to anyone's knowledge have there been previously recorded investigations by cave divers at this location?Enigmatically these potholes are situated at about the same level and just a short distance upriver from the major Litton Mill (Brow Well) Resurgence.Richard.
I'm intending to investigate water temperatures along the Wharfe from Loop Scar to Conistone in the hope of finding any hidden resurgences in the river bed. I'm waiting for a lengthy period of either hot or freezing weather which will maximise the temperature differential between the cave water and the river water. It might be a waste of time but will be a pleasant walk if nothing else.
I'm going to stick my hand in. I'll be using an old fashioned mercury thermometer and also have an infra-red model but am not sure whether the latter will be effective - it's something that I'll try within the next few days. Brow Well be used as a reference for underground water temperature (as it's known that the water source is several Km away) and a point in the river just upstream of Burnsall used as a reference for surface water temperature. There's no need for data loggers at this stage as a snapshot should suffice for this type of measurement.
Incidentally, back in '76, the Wharfe's flow at Ghaistrill's Strid virtually ceased but the resurgence just to the south (sorry, I've forgotten it's name) continued to flow. In very wet weather the flow at the resurgence doesn't appear to increase much. It's therefore possible that the water is derived from the Wharfe in a similar manner to the Loup Scar resurgence.
Question is - am I repeating work that you've already carried out?
It has always struck me ,that there should be a rising in /near the Wharf below Grass Wood ,but that may be to far up than you were thinking about.
Something similar, temperature readings down the Wharfe, was undertaken by WRPC members some years back. Worth contacting them. Also something around the confluence of the Skirfare and Wharfe, underwater arch reported.
Many years ago I remember a map of the area which showed four resurgences - Black Keld, Davy Keld, Ghaistrill's and Brow Well. Black Keld appears to 'account for' the Langcliffe/Mossdale water whilst Brow Well (along with mine levels in the Hebden Valley) accounts for the waters of the Yarnbury area.
The only other water that I know of is the small stream that has no obvious resurgence in the Dib Scar valley. The mini-Malham Cove of Dib Scar looks 'cavey' but would be a long term project for which permission probably would be difficult to obtain.
For this exercise, Loup Scar is a good place to start as it's easy to get a reference temperature for the river water (and a very pleasant walk) and it's not far to the main area of interest is to the north of Grassington.
Would it not be best to do this either in the dead of winter or the height of summer when the water temperature difference is most noticable?
Thanks for all your help and suggestions. All I need now is a heatwave. I'll post the results later this year.
Talking of water temperature and infrared drone flights, I recently met someone who is planning to do just that on a 2 km stretch of the Upper Ribble this summer. The aim is to look at the size and dynamics of cool water plumes produced by groundwater inputs which are useful refuges for fish during hot weather. I imagine that the resurgences in Ribblesdale are fairly well known so its unlikely to throw up any surprises but I'm looking forward to seeing the results nonetheless. If/when this technology becomes affordable, it could be a very efficient way of resurgence hunting.
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