Author Topic: Is it safe to go caving yet? Modelling cave flood events in Yorkshishire  (Read 4566 times)

Offline alanw

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Re: Is it safe to go caving yet? Modelling cave flood events in Yorkshishire
« Reply #25 on: October 07, 2020, 01:09:37 pm »
The rain / hail fall can be extremely localised. During the BPC winch meet in May 2008 there was a flood pulse down Fell Beck that swamped the platform the winch stands on. Only a few hundred yards away in the vicinity of P5, it was (fortunately) totally dry.

There are a few videos of the event on YouTube, e.g.

Offline blhall195

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Re: Is it safe to go caving yet? Modelling cave flood events in Yorkshishire
« Reply #26 on: October 07, 2020, 01:13:19 pm »
Some great points mikem & Bob Mehew

That ultra sonic cave logger looks awesome!

In terms of rainfall data I think you're right in that trusting a single source would likely lead to inacurate/misleading results depending on its location and mechanism by which water enters the cave. I think to begin with I'd cast the net quite wide around a cave in terms of rainfall data collection and see what the data looks like when compared to cave water levels over time.

This is definetly more a more complext probelm that I first thought and it's likely the model would need to have a large margin for error. Also taking local river levels into account sounds like a great idea too.

Here's a bunch of EA weather stations around Horton in Ribblesdale as an example.



Plots showing rainfall data from from the past week at all of the stations shown above.



This is a great idea.
For about 20 years I ran research projects at a couple of industrial research organisations.
One of the things I learned was that when you are first trialling an instrument you have built or modified you need to know what the results are going to be. If you don’t you have no idea if any surprises are due to genuine effects or your equipment not behaving as you expect.
I would not use either Peak or Sleets Gill as a first step. So far as I am aware no one (yet) understands how or why they respond to different sources of water, and monitoring those sources would not be straightforward.
In Derbyshire I might go for Giants, perhaps at sump 1. In Yorkshire perhaps Upper Long Churn. Both easily accessible and so far as I know the source of water in each case is obvious and rainfall data is available.
It is quite likely you already knew all this. If so please don’t be offended, but there has been no mention of it so far on the thread.
Good luck with it, and please do continue to post your progress.


I agree a pilot study on a cave with reasoably easy to understand/predictable hydrology would be a good place to start. I'm thinking somewhere that normally has welly deep water but occasionally floods, this way I might be work out signal drift over time as the water levels return to a baseline during dry periods I can do an aproximate recalibration, that is if the sensor remains precise but becomes inaccurate over time, something I'll have to look into. Alternativley I can leave a measuring stick in there and take manual water level readings for data calibration when I come to process the data.




Offline blhall195

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Re: Is it safe to go caving yet? Modelling cave flood events in Yorkshishire
« Reply #27 on: October 07, 2020, 01:23:12 pm »
The rain / hail fall can be extremely localised. During the BPC winch meet in May 2008 there was a flood pulse down Fell Beck that swamped the platform the winch stands on. Only a few hundred yards away in the vicinity of P5, it was (fortunately) totally dry.

There are a few videos of the event on YouTube, e.g.

I see, I wonder if strong localised showers are more likely to be picked up by radar. Something for me to look into. 

Online mikem

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Re: Is it safe to go caving yet? Modelling cave flood events in Yorkshishire
« Reply #28 on: October 07, 2020, 02:54:24 pm »
It's interesting that the basic shape of the rainfall patterns is similar on all charts, but with significant differences in the details.

Offline alanw

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Re: Is it safe to go caving yet? Modelling cave flood events in Yorkshishire
« Reply #29 on: October 07, 2020, 05:45:03 pm »
Some comments made here at the time of the May 2008 storm: https://ukcaving.com/board/index.php?topic=6364.0

Offline Russell Myers

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Re: Is it safe to go caving yet? Modelling cave flood events in Yorkshishire
« Reply #30 on: October 07, 2020, 05:49:44 pm »
The Craven Pothole Club in Horton in Ribblesdale adjoins the river Ribble and also Brants Gill.

If this location was of any use to such a project (river level monitors etc) I am sure the club would be happy to look at anything that would benefit the caving community   

Drop an email to the secretary if there is anything you would like the committee to discuss.

secretary@cravenpotholeclub.org

Ian
We have webcams picking up both the River and Brants Gill - see water levels https://www.cravenpotholeclub.org/     Fascinating to watch the flood pulses rise and fall plus the odd caver on their way to the Irish Sea.

A few years ago an angling organisation asked if they could install water level monitoring equipment in a box on one of our walls which we agreed to and once installed thought it was up and running until someone opened it and it was empty! So far as I know it has never been used. I think it is still there and would make a handy location for monitoring equipment if required.
JFK: Change is the law of life and those who look only to the past or present are certain to miss the future.

Online mikem

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Re: Is it safe to go caving yet? Modelling cave flood events in Yorkshishire
« Reply #31 on: October 07, 2020, 05:50:39 pm »
Looking at the rain gauges around Horton, they are typically all in the valleys, whilst precipitation is usually significantly higher on the hilltops.

Offline Pitlamp

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Re: Is it safe to go caving yet? Modelling cave flood events in Yorkshishire
« Reply #32 on: October 07, 2020, 07:38:21 pm »
Good point Mike. Several years ago we did an exercise to compare what fell at Gaping Gill with what fell at valley level, over a 17 day period (when the GG winch meet was set up). It's written up somewhere in an issue of CPC Record, in case that's useful for folk to be aware of.

My memory of the findings (obviously based on limited data) is that up to 50% more rain fell at GG but the difference was not as great on all of the days when rain was recorded.


Separately, the valid point was made about rain sometimes being very localised. However, this is most likely at the time of year when convectional rainfall strikes. At other times of the year (i.e. not summer) the rain tends to be more evenly distributed. I guess that, to explore this point properly, any monitoring should ideally be continuous over 2 or 3 years.

Online Robert Scott

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Re: Is it safe to go caving yet? Modelling cave flood events in Yorkshishire
« Reply #33 on: October 07, 2020, 11:17:10 pm »
Looking at the rain gauges around Horton, they are typically all in the valleys, whilst precipitation is usually significantly higher on the hilltops.
There is a weather station near the top of Meugher which lies between Mossdale & Nidderdale at about 570m. There is also work going on around Meugher to slow run-off using rolls of Coir.

Offline blhall195

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Re: Is it safe to go caving yet? Modelling cave flood events in Yorkshishire
« Reply #34 on: October 08, 2020, 10:20:30 am »
Have you seen this gadget?

https://reefnet.ca/products/sensus/

It’s about the size of a matchbox. It’s designed to be carried in a diver’s pocket, but you can just leave it in the cave for months. I understand the team surveying sump 3 and the surrounding cave in Cabouy, France have had a couple in the cave on submerged bolts for several years. Catches the flood pulses which are 10m+ high, which is astonishing considering the size of the cave and discharge area.

https://m.facebook.com/thehiddenriverproject/

Look for the post on 18th Oct 2019 for the nice charts with accompanying weather data.

Contact Torsten for more info, he’s been exceptionally helpful with some therion code for me and is really enthusiastic.

Thanks Steve, the Sensus devices they used look like exactly the kind of thing you'd want for a project like this, I've got in contact with Torsten to ask for info on the device, cheers.

Online aricooperdavis

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Re: Is it safe to go caving yet? Modelling cave flood events in Yorkshishire
« Reply #35 on: October 08, 2020, 02:18:20 pm »
We have webcams picking up both the River and Brants Gill - see water levels https://www.cravenpotholeclub.org/     Fascinating to watch the flood pulses rise and fall plus the odd caver on their way to the Irish Sea.

It doesn't look like it would be that hard to extract water depth information from this one to be honest!

Online mikem

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Re: Is it safe to go caving yet? Modelling cave flood events in Yorkshishire
« Reply #36 on: October 08, 2020, 07:17:38 pm »
Just more effort than the automated gauges...

There are various others on rivers that may not have EA Gauges, set up for fishermen:
https://www.farsondigitalwatercams.com/locations/aberlour

Offline blhall195

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Re: Is it safe to go caving yet? Modelling cave flood events in Yorkshishire
« Reply #37 on: October 09, 2020, 12:37:10 pm »
This is a good shout actually, I've almost finished making a water level logger that sits inside a box that looks like this (113mmx73mmx60mm)/(L*W*H).



It uses a waterproof ultra sonic distance measuring sensor with 5m range and 1cm resolution, it was fairly cheap £10 but good enough for a proof of concept you can get really good ones with mm resolution and 10m range for £100.

The idea would be I'd have it sit above the streamway in the cave and it'd log the water level height, would have to be clever about where I put it though as the prototype isn't completly waterproof (IP67).

Ideally I'd put it on a bridge somewhere that already has a monitoring sensor to check it's working properly before leaving it in a cave.

I'd just need to work out how to secure it to the bridge in a way that's discreate enough for people not to care it's there, maybe alongside the existing river level monitoring equipment.

Offline Tim Pickering

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Re: Is it safe to go caving yet? Modelling cave flood events in Yorkshishire
« Reply #38 on: October 09, 2020, 04:06:23 pm »
What a fascinating thread?

This is something that greatly interests me also, not particularly from any practical viewpoint but more personal curiosity. I work in one of the show caves in the Dales, and it responds in so many different ways to rainfall. I would love to understand the relationship between all the different variables and the cave's response. I do intend, when time permits, to investigate this further. River stage seems to be an unreliable indicator on its own. I am pretty new to the area and still have a lot more exploring of the immediate vicinity to do, and my knowledge is limited to a couple of undergraduate hydrology modules but I feel it's a good starting base.

I'll be following your progress with great interest.

Online PeteHall

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Re: Is it safe to go caving yet? Modelling cave flood events in Yorkshishire
« Reply #39 on: October 09, 2020, 05:03:38 pm »
Would it be incredibly far-fetched to have a monitoring station underground, (perhaps charged by a water driven turbine?), with a cave-link type communication to a weather station on the surface?

You could potentially see live(ish) data for the cave online before planning your trip  ;D
The distance between stupidity and genius is measured only by success.

Online mikem

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Re: Is it safe to go caving yet? Modelling cave flood events in Yorkshishire
« Reply #40 on: October 09, 2020, 05:29:44 pm »
Although helpful, levels will invariably have changed by the time you get there - you also want to know whether it's rising or dropping!

Offline TheBitterEnd

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Re: Is it safe to go caving yet? Modelling cave flood events in Yorkshishire
« Reply #41 on: October 09, 2020, 05:59:16 pm »
It seemed to me that the rainfall radar would be useful for this kind of thing because it gives intensity and location so I asked the met office if they made historic rainfall radar data available but they don't and apparently they don't even record it. I did wonder if it would be possible to screen-scrape the rainfall radar map but never got around to trying.
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Online PeteHall

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Re: Is it safe to go caving yet? Modelling cave flood events in Yorkshishire
« Reply #42 on: October 09, 2020, 06:15:57 pm »
Although helpful, levels will invariably have changed by the time you get there - you also want to know whether it's rising or dropping!

Depends on the cave. I'm particularly interested in the local water table in the bottom of Charterhouse, which rises and falls very slowly, so you can never predict if the lower reaches will be accessible, regardless of recent weather...

I've been planning to chuck a couple of data loggers down there to try to correlate it with rainfall data, but not got around to it yet...

While the science interests me, I'd actually be happier if I knew how far I was likely to get before setting off so I don't waste effort carrying kit that won't get used...
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Offline Chocolate fireguard

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Re: Is it safe to go caving yet? Modelling cave flood events in Yorkshishire
« Reply #43 on: October 09, 2020, 08:17:38 pm »
Would it be incredibly far-fetched to have a monitoring station underground, (perhaps charged by a water driven turbine?), with a cave-link type communication to a weather station on the surface?

You could potentially see live(ish) data for the cave online before planning your trip  ;D
A couple of years ago there was a thread where using an underground stream to produce electricity via a water wheel and generator was mentioned (I think it involved recharging a battery that would be used to power a ventilation fan).
Out of interest I bought a cheap motor/generator from eBay and connected the output via a switch to a 12V 5W car bulb. With a 15cm spindle through a hole in the end of the shaft it was possible to turn the thing very easily with the switch open, but as soon as the bulb was switched across the output it became much more difficult.   
Nobody ever gets close to lighting the bulb at normal brightness. With a couple of meters in the circuit the maximum output I can manage is less than 2W, and even assuming an efficiency of perhaps 20% (like I said, it was cheap) I guestimated from the feel of it that a water wheel to drive a more efficient one wouldn’t be a practical proposition using the small and intermittent streams nearby.
Google found several articles on Cave Link. The only technical stuff was in German, which I don’t read, but there was a picture of some hefty looking batteries in the bottom of the box. There were some things that might have been power consumptions but I couldn’t really tell.
So the turbine idea might be a goer, but it depends heavily on the power needed and what streams are available nearby.
I have my doubts – conservation of energy has bug***ed up a lot of good ideas over the centuries!

Offline Bob Mehew

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Re: Is it safe to go caving yet? Modelling cave flood events in Yorkshishire
« Reply #44 on: October 09, 2020, 08:19:42 pm »
https://www.cave-science.org.uk/ contains a mine of data on cave climate.  I am unsure if Tony Goodsell's water depth recorder data is included but is probably available.  You might like also to think about drip rates verses rainfall which I guess is the primary link for normal conditions.  If you are only interested in surges, then it is back to rain, state of land and drainage basins.
It uses a waterproof ultra sonic distance measuring sensor ... as the prototype isn't completely waterproof (IP67).
Given normal variations in atmospheric pressure can equate to 0.3m of water, it is difficult to make something waterproof.  Tony's detector uses O rings.  So you may wish to install a bag of silica gel to absorb any moisture which gets inside plus apply a conformal coat to your electronics to minimise the impact of moisture.  My kit lasted two weeks before what I presume was moisture killed it.  So plan on returning frequently to check things

Online aricooperdavis

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Re: Is it safe to go caving yet? Modelling cave flood events in Yorkshishire
« Reply #45 on: October 09, 2020, 08:28:25 pm »
I asked the met office if they made historic rainfall radar data available but they don't and apparently they don't even record it. I did wonder if it would be possible to screen-scrape the rainfall radar map but never got around to trying.

You can actually get the layers through the DataPoint API I think, which is very convenient for saving them whilst you're running the experiment.

Offline TheBitterEnd

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Re: Is it safe to go caving yet? Modelling cave flood events in Yorkshishire
« Reply #46 on: October 09, 2020, 08:44:09 pm »
Looks like things have moved on since I asked them.
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Online mikem

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Re: Is it safe to go caving yet? Modelling cave flood events in Yorkshishire
« Reply #47 on: October 09, 2020, 08:54:44 pm »
Tim Pickering - showcaves being normally resurgences, their water is often collected from a very wide area, where differing rainfall over the catchment may result in variations in observed levels & timings. Some of that water will come directly through large conduits, so providing rapid & often muddy influxes, others through tiny passages, some may cause flooded chambers to overspill, thus forcing cleaner water through the system & sometimes that overflow may be overwhelmed (or become blocked) & rise to another passage that takes it off in a different direction (plus all the variables in ground / saturation conditions mentioned already)...

Online mikem

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Re: Is it safe to go caving yet? Modelling cave flood events in Yorkshishire
« Reply #48 on: October 09, 2020, 09:03:18 pm »
Looks like things have moved on since I asked them.
I think the API includes rainfall records from weather stations, rather than radar data, which could be interpolated for sites in-between.

Online Ian P

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Re: Is it safe to go caving yet? Modelling cave flood events in Yorkshishire
« Reply #49 on: October 09, 2020, 09:53:39 pm »


Ideally I'd put it on a bridge somewhere that already has a monitoring sensor to check it's working properly before leaving it in a cave.

I'd just need to work out how to secure it to the bridge in a way that's discreate enough for people not to care it's there, maybe alongside the existing river level monitoring equipment.

Not sure if any use (the tech side of things is out of my league).

Opposite the webcam quoted above, we have a building adjoining the river where a simple timber bracket could be fitted, projecting over the river at a height to suit. The area is secluded and not easily accessible.

Making and fixing a timber bracket is in my skill set and I am sure the CPC would be supportive.

Ian


 

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