Anyone been to JB lately? Thinking of going next week.
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Anyone been to JB lately? Thinking of going next week.
I don't think it really ever changes. Quite a bit of flow, quite a bit of viz, 69F water.
I agree with Victor on this. The flow in JB changes with the amount of rain we have been receiving. With more rain there is generally more flow. If the flow gets high enough the viz can get a little milky with maybe 30' of viz. This I believe is due mainly to sand / silt moving around in the back of JB due to the increase in flow. It seems to be more noticeable after a drought. Now if some farmer decides to fill in a sinkhole upstream you can have problems too. Generally all the caves on the Mill Pond are not affected by the rain / river levels that much. The viz in the shallower tunnels of Hole is generally better in the summer. The deeper tunnels such as the Century Tunnel and Consolation Corridor are clear. My theory on this is the water temperature of the Mill Pond water. As we all know hot water rises and cold water sinks. I think during the winter the Pond water is cooler than the spring water and you get intrusion from it and some sinkholes such as the one down by Day Loop road. If you are planning a trip and are worried about what conditions will be the Mill Pond is as safe as it gets in my opinion.
Only dove JB last week and vis was at least 70' to the second T. Flow was less than the "new normal," or less than rip-roaring, but more than about 2-3 years ago when I believe it was generally considered a low flow cave.
I've seen the flow down every now and then, but I've never heard JB being called a "low flow cave."
Quote:
Originally Posted by Slüdge
My how time flies! Checked my sidemount cert., and it was 3-4 yr. ago when I started diving JB, and heard it was a low flow cave. Mostly heard that from 2-3 instructors, but also from a couple of new buddies, and especially before my first time in Madison - which was described by comparison as having flow. Of course, I wasn't cave-diving 10 or more years ago when the flow in JB was typically comparable or greater than it is on any given day these days.
The JB flow does change with rain. When I first started diving it the flow was pretty low. In fact, it was almost non-existent. I remember doing a single stage swim dive to Stage Rock back then. A couple weeks later we had 20 some inches of rain in about 36 hours and everything changed. The flow increased dramatically. First, JB blew out. Yes, literally blew out. There was only about 5-8' of visibility that Saturday. By Sunday it had cleared up to 40' or so. A few days later it was back to normal except flow was ripping. It was the highest I had ever seen it. This happened almost 6 years ago in 2009.Quote:
Originally Posted by bamafan
https://www.youtube.com/watch?v=FObq6ZQ15MI
We've had decent rain every year since then and the flow has remained, although not as bad.
As for Hole in the Wall, my theory is conditions there are more affected by the Indian Springs golf course than by rain intrusion in the sink hole or the other entrance. The golf course has to start pumping more fertilizer into the greens and fairways in the winter to keep it looking nice and that all affects the visibility in Hole. This is especially apparent in certain areas of Hole and looking at the overlay in comparison to those areas and the golf course, they are pretty close. Of course, this could be affects of what they did 17 years ago. I'm not sure how the seepage works and if it is close to 17 years on the mark or varies by a few months. But I have also seen Hole run crystal clear throughout the year and have bad visibility during the summer. So it probably varies.
Sink hole? Other entrance?
Nothing to see here. Please move along.Quote:
Originally Posted by TracyN
Dove JB yesterday (10/8) flow was down from when I last dove it back in Jan. swam back to around 2800ft before turning. First dove JB back in 2009 if memory serves. Then flow was down, not knowing any better returning the following years to find it back up.
FYI also dove Ginnie and the flow there also seemed down to me.
Al
Lol!!! :-)Quote:
Originally Posted by Draker
Thanks, guys. Just wanted to hear from somebody that had been lately. Looks like I'll be calling Edd 's in the morning!
Have you been golf ball diving again Rob? Don't you just hate it when your golf balls land in a sinkhole. :-) :-)
We dove JB on 10/9 and 10/10. Viz was crystal clear, and the flow was down. On both days we easily swam (single stage) to King's Canyon.
While I don't have a lot of experience in the Mill Pond, my guess is that the primary reason viz deteriorates in winter in normal years is because there is little or no gradient in water level between the lake and the water table above the cave, which allows the increased density of colder lake water to push lake water into the cave system (where water is warmer and has lower density). Years where the viz is bad in summer, the lake is probably high relative to the water table and years where the viz remains clear in winter are probably where the water table is high relative to the lake.Quote:
Originally Posted by RN
Jason, I could see where that could be the case. Except it doesn't happen in the other caves on the Mill Pond. Twin Cave's entrance is in the floor of the pond away from the bank, unlike Hole in the Wall, and visibility in there is pretty constant year round.
The elevation of the entrance doesn't really matter all that much - but rather the elevation of the water table in the springshed. If there is perceptible water flow in a cave, then the water table in the spring shed is sufficiently high that temperature-driven density differences won't be able to cause lake water to sink into the cave. JB obviously has water flow. According to conditions reports (because I've not personally been to either of these caves), Twin seems to have very low flow whereas HITW has no flow. As a result, flow would prevent density-driven flow into JB and Twin but not HITW. In any case, I could easily bring up a bunch of low-cost temperature loggers and install them in the lake and various parts of caves if folks were really interested.Quote:
Originally Posted by RN
Would be an interesting study. I think some of your hypotheses are good,because when a "turn over" does occur, I have seen domes in HITW have warm,clear spring water, and the floor/mid-column area have cold water with poor visibility.Quote:
Originally Posted by jason
Rob brings up a good point regarding the gold course. Has the recharge area for HITW ever been mapped out, and would surface nutrients from the gold course be part of this?
I think the primary reason that nitrates are unlikely to be the cause is the seasonality of the visibility decline.Quote:
Originally Posted by Kelly Jessop
Actually, Hole and Twin are about equal in flow. I've felt higher flow in Hole on occasion. One thing about Hole is there are 2 main passages that both dump out of the same hole to the pond. The flow from each side is different at times. I've seen the flow from one side overpower the flow from the other and it gives the appearance of a siphon on one side for several hundred feet until the opposing flows equalize. This happens from one side or the other. Not sure why it's not consistent. I've just witnessed that it's not.Quote:
Originally Posted by jason
I would love to get data on this. I think the state would also be very interested. I can help you set these up and we can even look at overlays to decide where in the systems these loggers would best be positioned.
The seasonality also corresponds with colder times of year when the golf course would be receiving more fertilizer to keep it healthy when it otherwise wouldn't be because of colder temperatures and less rain.Quote:
Originally Posted by jason
But this is your field of expertise. I'm just basing my theory on my observations over the past 10 years. I may be way off on this because I really don't have the knowledge that you do Jason.
I'm in the process of setting up my lab at USF, so I'll order a bunch of temperature loggers and we can figure out the best places to install them. If I'm not able to make it up there in the next month or so, I can always turn the loggers on here and send them up with instructions for installation.Quote:
Originally Posted by RN
And I'm merely speculating without any first hand knowledge of the caves in question.... :)Quote:
Originally Posted by RN
Over the last two decades I have seen visibility decrease. In HITW, upstream was always crackling blue, but the water seems more dingy frequently. This may be attributed to nutrient loading.Quote:
Originally Posted by jason
Jason, your speculation is pretty good. There are about half a dozen different water sources for HITW. My observations are in line with the temperature gradient/densities for the seasonal vis. change in the front of the cave.Quote:
Originally Posted by jason
The vis turnover is most easily observable after the first strong rain of winter. If we've had cold conditions, the water in the front of the cave doesn't change very quickly. If you have those conditions of cooler pond water, the next good rain really gets the system syphoning the pond water.
Flow probably lessens the effect but even when HITW has flow you can still see pond water going into the system. If you sit in the entrance restriction you can watch cold water going down and the spring flow coming out. Also, you know the issue is working from the cavern into the system as poor conditions start near the entrance and work their way back vs starting in the back and working their way forward.
Kelly, I don't doubt the vis is lower more often, but the issue in discussing is absolutely seasonal. Reduced water quality means it hangs around longer and the effect is even worse, but I think the mechanism is always present.Quote:
Originally Posted by Kelly Jessop
That what I was talking about in the beginning of post #18.Quote:
Originally Posted by Ben M
I think the golf course would only be affecting the source water coming out of the passages around the 1st downstream T. There are other clear and poor sources waters in addition to this area.Quote:
Originally Posted by Kelly Jessop
I agree I think there are a couple dynamics going on. Anybody plot the recharge areas though?Quote:
Originally Posted by Ben M
Not individually, but as part of the pond.Quote:
Originally Posted by Kelly Jessop
http://publicfiles.dep.state.fl.us/D...-01_NWFWMD.pdf
Yes, we narrowed down the recharge areas and were able to track the true watersource passages in Hole in the Wall. I believe some people will be in for a surprise in the near future.Quote:
Originally Posted by Kelly Jessop
The golf course sits over areas both on the upstream and downstream sides. The worst of the visibility, from my experience, is typically in the upstream tunnel, especially around the 600-800' penetration range. This also happens to be a section of the system that runs directly underneath the course. Other passages run under it or next to it and seepage probably doesn't occur directly down through the ground but rather will take the path of least resistance.Quote:
Originally Posted by Ben M
Jason, can you share a link for the loggers you're using? Are they temperature only or can you pipe in other data?Quote:
Originally Posted by jason
-Jon
I use these for anything that might get much deeper than 100 feet (including flood peak) - http://www.onsetcomp.com/products/data-loggers/u22-001. There is a cheaper version that works well for shallower sites.Quote:
Originally Posted by jlillest
Jason, Let me know as well. I have a budget for data loggers (about $5k) and could pay your way to Pensacola for a seminar at UWF, like we did for the nss/cds mini workshop. I can also hit jb and the millpond on a regular basis. BillQuote:
Originally Posted by jason