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High Water Recorder

PostPosted: Mar 31, 2008 9:24 am
by cavemanjonny
Does anybody know of a cheap and/or easy to build device for recording how deep water gets? The crawl I'd like to check has all kinds of stuff stuck in the ceiling, and I'd like to figure out how much rain is required to raise the water that high.

I guess I could jam a cup or something in the ceiling, and check to see if it's full after every rain event, but I wouldn't trust that at all. I was thinking maybe even something like a floater that can rise with the water but can't sink down. Maybe mounted to a camming device or something. Any ideas?

Re: High Water Recorder

PostPosted: Mar 31, 2008 10:33 am
by tncaver
I know this may sound overly simple, but if you can check the cave on a regular basis, you can simply look of a
high water mark. Usually when I visit a cave after a recent rain (within a week) there is an obvious darker high
water mark on the cave walls that shows exactly how high the water got after the last rainfall.

Re: High Water Recorder

PostPosted: Mar 31, 2008 10:39 am
by cavemanjonny
tncaver wrote:I know this may sound overly simple, but if you can check the cave on a regular basis, you can simply look of a
high water mark.


This might definitely be an option. I'll have to see if there are any obvious lines on the wall next time I'm in there.

Re: High Water Recorder

PostPosted: Mar 31, 2008 11:59 am
by adleedy
I also wondered about a recorder for high water, with a floater that could raise, also thought about having this trip a video recorder and spot lights so you could see the cave go into full flood in real time :grin:

Re: High Water Recorder

PostPosted: Mar 31, 2008 12:07 pm
by cavemanjonny
adleedy wrote:also thought about having this trip a video recorder and spot lights so you could see the cave go into full flood in real time :grin:


That would be too cool!!

Re: High Water Recorder

PostPosted: Mar 31, 2008 12:16 pm
by Ralph E. Powers
jprouty wrote:
tncaver wrote:I know this may sound overly simple, but if you can check the cave on a regular basis, you can simply look of a
high water mark.


This might definitely be an option. I'll have to see if there are any obvious lines on the wall next time I'm in there.

You can also try some sidewalk chalk (swipe some from a kid or something) and make a small mark on the wall (yes, yes I know but it's NOT graffiti... it's scientific research :roll: ) then go back (as often as the gas prices will allow) and make other marks so to see the difference... the chalk shouldn't be harmful and will wash off...
Either that or a tiny dot of your girlfriend's nail polish

Re: High Water Recorder

PostPosted: Mar 31, 2008 12:34 pm
by cavemanjonny
Actually, that's a brilliant idea! I could make a stripe of chalk all the way up the wall, which is only about 2 feet tall, tops. It should wash away up to the point of the high water!

Re: High Water Recorder

PostPosted: Mar 31, 2008 2:04 pm
by Phil Winkler
Jonny, you can also buy water detecting paste that changes color when water touches it. You could anchor a yard stick or something in the passage, slather on the paste and badda-bing.... It is normally used to detect water bottoms in fuel storage tanks.

Re: High Water Recorder

PostPosted: Mar 31, 2008 2:08 pm
by John Lovaas
The chalk seems like an easy low-tech way of getting the job done.

I've known folks who coat a rod with Kolor-Kut Paste-

http://www.forestry-suppliers.com/produ ... sp?mi=3379

and place that in a open ended PVC tube(so the raccoons don't lick it all off) and secure it in the passage. The color change indicates the high point.

I've also seen an arrangement(it was at Lilburn Cave, CA this summer) that seems like a good idea as well. Small cups, fabricated from small PVC tubes, were secured to a vertical rod- every foot, as I recall. My thought is that as the water level rises, it fills the cups. As long as you visit the site before the water in the cups evaporate, you'll know the high point.

I've been using several Onset temperature loggers in a MN cave to determine just when a sump is open. The "sumpy bit" of crawlway is close enough to the entrance that you can see small diurnal air temperature changes. When the area sumps, you lose the diurnal changes, because the temperature logger is underwater. I've got one on the floor and one on the ceiling of the passage. The loggers are under $50 each, and can be used for all sorts of cool(pardon the temperature pun) applications.

The most expensive solution is to purchase a pressure transducer depth logger. The magic number for those is around $600 US- I'm waiting for prices to fall on those, but it ain't happening ;-(

Re: High Water Recorder

PostPosted: Mar 31, 2008 2:19 pm
by cavemanjonny
Phil Winkler wrote:Jonny, you can also buy water detecting paste that changes color when water touches it. You could anchor a yard stick or something in the passage, slather on the paste and badda-bing.... It is normally used to detect water bottoms in fuel storage tanks.


Yet another great idea. I could use chalk on a yard stick and the paste on a yard stick, to compare the methods as well! You guys are geniuses!

John Lovaas wrote:The most expensive solution is to purchase a pressure transducer depth logger. The magic number for those is around $600 US- I'm waiting for prices to fall on those, but it ain't happening ;-(


That would be awesome! A yardstick and chalk are more inline with my budget, however :-).

Re: High Water Recorder

PostPosted: Mar 31, 2008 2:37 pm
by Andy Shoun
OK, here is my idea. The yardstick with paper taped along the full lenght, make a mark every 2 inches on the paper with a marker. The ink will bleed and indicate the high point of the water. It is like that chemistry experiment where you use a solvent to seperate black ink into a spectrum of inks.

Re: High Water Recorder

PostPosted: Mar 31, 2008 2:40 pm
by cavemanjonny
Andy Shoun wrote:OK, here is my idea. The yardstick with paper taped along the full lenght, make a mark every 2 inches on the paper with a marker. The ink will bleed and indicate the high point of the water. It is like that chemistry experiment where you use a solvent to seperate black ink into a spectrum of inks.


Man, I wracked my brain trying to think of something simple. You guys are amazing! What are your thoughts on cold fusion?

Re: High Water Recorder

PostPosted: Mar 31, 2008 2:53 pm
by Scott McCrea
You could substitute the yard stick for a cord. It might be a pain to carry a yard stick into a cave. You could smear the paste or rub the chalk or color with water soluble ink on the cord then tie it to something high and anchor it to the floor with a heavy rock or something. I think I might try this too. Great ideas!

Re: High Water Recorder

PostPosted: Mar 31, 2008 3:06 pm
by cavemanjonny
Scott McCrea wrote:You could substitute the yard stick for a cord. It might be a pain to carry a yard stick into a cave. You could smear the paste or rub the chalk or color with water soluble ink on the cord then tie it to something high and anchor it to the floor with a heavy rock or something. I think I might try this too. Great ideas!


I guess you'd want to use a cord that won't stretch or contract when it gets wet and dries.

Re: High Water Recorder

PostPosted: Mar 31, 2008 4:01 pm
by ggpab
Several excellent low tech options made, but if you factor in your time and gas, then consider the scientific $125 solution.

ReefNet is a company that makes compact internally logging 'scuba dive loggers'. If you are a diver with this on your harness, then the device gives you a neat dive profile. If you fix the device in location in a cave for example, it then measures the changes in water level above it. If the device is dry, the logging does not happen, and logging immediately starts up again once it is submerged by 1-2 feet of water. I would actually suggest putting the device in the lowest possible location you can reach including in a streamway. Consider placing an anchor to attach it to. Be aware to NOT USE METAL TO METAL CONTACTS when attaching the device since that is a great way to set up a bi-metalic current, and thereby destroying the instrument. Braided nylon rope works really well. The default sampling interval is 10 seconds which is great for a scuba dive but way too much for what you need. You can reset the sampling interval and I would suggest every 15 minutes (96 points a day) since that will then allow for future analysis using fast fourier transforms (FFT). Don't collect less data than that since you then loose alot of the high frequency variation (more on that if you want...). If you want to collect more data, then go down to every 5 minutes. At 15 or even 5 minute intervals, the Sensus will run for years and has enough memory to handle long deployments like that. Last week I was just suggesting these as the long term monitoring solution needed in the Mammoth Cave area for assessing when overflow passages become activated. Dye tracing just does not work well for getting data on these low frequency (ie rare) but environmentally significant (ie contaminant transport) events. MInd you, the water level does not tell you how fast or which direction the water is flowing either so there are pros and cons.

http://reefnet.ca/products/sensus/

You will also need the download unit so if you are only getting 1 then I guess the buy in cost would be somewhat higher. Or mail me your unit and I can download it for you.

As an added bonus you also get temperature. This is really neat because you can then look at the data and start telling where the water might be coming from. Is it cool groundwater being pushed through the system? Is it warmer surface water passing as a slug through the passage? Does the source of the water change in the middle of the flood pulse? Hint - bring a thermometer with you when you put the Sensus in and measure the temperature of ALL water you find in the cave. This will then allow you to know the typical temperatures of your various waters and use the temperature as a non-conservative tracer.

Cheers
Trish Beddows