Boil Holes???

[FiddleCaver]

OK, I ran across THIS while surfing and was reminded of a similar hole that has existed for a long time right in a creek off of the Buffalo River. I've heard stories that at times the hole would gush with water, and be quite deep. Personally, I've never seen it all that deep looking but it always seems to have a few feet of water in it, which is something because except in rare cases, this creek is always dry. There are lots of huge caves in the area, and lots of water that flows underground. Anyway, to the point, I'm curious about the formation of these holes as it seems that it is a little different than a sinkhole and if anyone has ever explored/dug in one of these when it's dry.

[ian mckenzie]

Never heard the term before, but it sounds like a boilhole is simply a seasonal or occasional spring, in the same way a sinkhole is a seasonal or occasional sink. Of course, in parts of the US, 'sinkhole' can have a slightly different meaning, often applied to a suddenly-occuring collapse, so I guess a boil hole is a suddenly occuring spring. Where I am, watertables are not so high that we get either.

[Teresa]

Google estavelle. That is the term for a reversible swallow hole/spring which either takes or emits water depending on rainfall.

They are kind of cool...sort of at the cusp between a cave and a spring. The often occur in areas of dipping bedrock, or at least in hilly areas where the water off the surrounding hills runs to a valley with a relatively impermeable subsurface drainage. In drought times, with the water table low, they take water. In wet times, with the water table high, they resurge.

Can't say I know anyone who has explored them, but considering the volume of water, they likely look more like divable springs than caves. As the pictures show, when they flow-- they FLOW!

[ArCaver]

The boil holes I've seen locally have no entry. The water comes up out of gravel and sand beds. At times it does appear to be boiling. I wonder if they could be epikarst features?

[tncaver]

There is a place in White County, TN, known as The Boils. It is the
resurgence of the Caney Fork River and it does boil up at times from
under a placid deep pooled section of the river at the base of a 100
foot high bluff. The river insurges a few miles upstream and resurges
under water. In drought, when no water insurges, the "boils" are quiet.
In wetter weather the "boils" can plainly be seen. It might be possible
to dive the "boils" in drought weather when there is no insurging
water and therefore no boil.
Hmm...maybe I should contact the local cave divers about that.

[Teresa]

"Insurge" is the injection of water under pressure. I don't expect that is what is really happening here. Losing and gaining stream reaches in karst areas are extremely common because of the nature of the bedrock. It's also fairly unlikely that a person would be able to dive a spring in a river bottom without a lot of underwater digging of stream sediment.
It's possible, of course-- many springs have been dug open, then dived, but in the case of river springs, dug areas (if penetrable at all) will gravel shut in no time flat. River bottom springs usually require low flow conditions for diving-- this is precisely the time a boiler is likely to be dry.

I know of an estavelle which is also a ball mill-- In dry times, it looks like a gravel floor beneath an outside steep cliff. After a couple days of heavy rain during a wet season, the water which resurges churns gravel in the bottom of the slight depression and 'mills' it into rounded cobble.

You probably could contribute more to science by measuring rainfall and discharge during a storm event at the boil hole.

[tncaver]

Because the water literally boils out from under the pool level,
there is a good chance it flushes most gravel and debris out of
any existing passage.
Obviously the current would be too forceful for a diver to penetrate
except in drought condition when the flow was nil or non existent.
As for contributing to science...I think those of us who can contribute,
do so in whatever way we are most capable.

[Teresa]

Because the water literally boils out from under the pool level,
there is a good chance it flushes most gravel and debris out of
any existing passage.

Do you have an estimate of flow on your boil hole? I know of five major permanently flowing springs with average flows of 100 million, 50 million, 49 million, 45 million and 37 million gallons of water daily, (or 165, 78, 69.5 and 57 cfs) all of which periodically close with gravel chokes. The one @ 45 million is in the bottom of the regional master stream for that area, and it has to be dug more often than the others. All are typical bent filler tube funnel basins, with the water flowing upward under hydrostatic pressure, and capped with a pool -- not a sideways flowing cave exit.

The one at 50 million gallons per day has a permanent sand/gravel choke, which cannot be successfully dug (they've tried, with everything up to gravel-mining backhoes.)

Just because the water 'boils' doesn't mean it comes from an open conduit.

[tncaver]

Teresa,
I know what you mean. The easy way to find out is to have a willing
cave diver check the "boil" out. No science required, just a willing
diver with guts and determination.
Teresa, come on down to TN and perform that flow rate experiment.
I'd love to know the details and see how you do it.

[FiddleCaver]

Most of the time, this hole just sits there full of water. When it rains, it will flow even if the creek is dry. There are lots of caves around there but all are above the creek level. It's evident from this hole and the fact that the creek is almost always dry even after lots of rain that there is significant karst geology even beneath the creek level so it got me wondering. I have no interest in diving but am very interested in finding out where all the water is disappearing to in the creek as well as in the several caves in the area. I've got a feeling that this is a resurgence from a couple of other caves in the area, but without dye tracing it's impossible to tell. Now I'm curious if these things are usually associated with an actual karst passage or if this is just the creek water resurfacing from under the creek bed.

If I had a picture I'd post it but I don't. It looks almost exactly like the one in the link on the original post however.

[tncaver]

Fiddlecaver and Teresa,
Perhaps what you are describing is different from what I am describing.
But one way to find out about either is to have them checked out
by qualified people if you can find someone capable and willing.
One thing I've learned about caves is that they don't always do what
is expected of them. Leads that look great can crap out quickly and
leads that look like duds can suddenly open up into huge caves.
Part of the beauty and fascination of caving I'd say.

[George Dasher]

Boil holes are simply springs that put out a lot of water.

They can be underwater in a stream and raise the water surface, which is called a boil.

Or they can be abovewater and are simply springs that put out a large volume of water.

They can be intermittent or permenant.

The Blue Hole at Ictatuckee (??) Springs State Park in FL is a good example.

[Teresa]

Boil holes are simply springs that put out a lot of water.

They can be underwater in a stream and raise the water surface, which is called a boil.

Or they can be abovewater and are simply springs that put out a large volume of water.

They can be intermittent or permanent.

The Blue Hole at Ictatuckee (??) Springs State Park in FL is a good example.

With all due respect, George, (and I sincerely mean that) I think we've got some regional differences in terminology here. What you are describing is a properly a vaclusian spring, which does come in two states: the boiling kind and the blue hole kind. What you call a boil-- the raised extent of a resugence under water which is flowing at such pressure as to raise the surface of the stream in an agitated manner-- we call a stack (short for haystack, though it much more resembles a fire hydrant with the top off) around here. No diver is going to get anywhere near into one of those stacks at full bore. The AGI Glossary shows 'boiling spring' as a Jamaican karst term for a spring with an agitated flow...and that, too, is the common name of a number of springs showing that behavior in Missouri-- i.e., Boiling Spring in Texas County (which doesn't really boil) and Boiling Spring, in Pulaski County, beneath the Gasconade River, which does look like a clearer, bubbling circular section of the river. I'm not sure if it ever gets much of a stack on it, as does the lower exit of Greer Spring-- colloquially called "The Boil". However, again, at least around here, one can have a stack on a blue hole type during high flow (I'm thinking of Maramec or Alley, both of which are seldom agitated under normal conditions). I'm not sure I would call the Blue Hole at Ichetucknee a "boiling" spring -- you may have seen it at a higher flow than I.

The photos of the original poster showed an intermittent spring which was dry or at subsurface water level except after a rain, at which time, it became an agitated, apparently multi cfs flow. That seems to be a different animal than a permanent spring with different flow rates. If a spring basin is large enough (think Bennett Spring) it can be quite agitated at depth, enough to make the gravel boil) but apparently placid on the surface.

It's too bad I'm not in Tennessee-- it would be neat to do some dye tracing of this hole at low flow, and see where the water comes out when it is not resurging from it. That's why I called it an estavelle system...what the original poster was describing is more typical of an estavelle than of a vauclusian spring showing a stack at high flow, and a blue hole at low flow.

[George Dasher]

Teresa:

You may be correct, but I'm sticking with my definations--mostly because I like to keep things simple.

I tend to fall asleep during long definations...

george

[Lost]

So who is going to dive it? I'm laid off from work and have a little time.