How Did This Happen

[thmoose51]

If someone in the know wouldn't mind giving a little lesson I would certainly be grateful for the info. Just exactly what is the process in the flooding of the caves and how often does it occur? What can we expect to see over the next few weeks and months as far as reports of silt clinging to walls, debris in the caves, flow and anything else you know of that someone of my limited knowledge of these types of events might like to know?

I started my training about two years ago and this is the first spring flood I have seen.

I eagerly await my edification..

[Sludge]

It used to happen every year.

Basically, it would rain a lot in the Spring, causing the rivers to rise. There is a certain hydrostatic pressure associated with each cave, and when the water rises, the pressure is overcome and water flows into, instead of out of, the cave. It can be called reversing, recharging, siphoning, etc.

It used to be an annual event, but we went several years without it happening.

[FW]

It was worse this year for several reasons, some going back for decades.

Around 30 or so years ago, a project was begun to prevent fires in the Okefenokee swamp. They built a structure, called a "Rill", like a dam, or dike. The idea was to keep some water in the swamp to put out fires. Then the environmentalists said fires were a good thing, so the Rill wasn't used much.

About a year ago, due to prolonged drought, a big fire started in the Okefenokee, and they closed the Rill to help put it out. For some reason it was never opened up, until this spring. When the "wet season" started, the swamp begin to over fill, so the Rill was opened, allowing a record amount of water into the rivers that drain the swamp, and they rose very rapidly.

I have seen many floods in north Florida, but never one that happened as fast as this year.

[jmaddox]

those silly environmental engineers. messing up our caves trying to put out fires. wait, environmental engineer, is that an oxymoron? Hey wait again, I have a great idea, lets make em all managers! ahhh I crack myself up. sorry to all of these engineers in management that i have offended.

--jm

[Serota]

I've heard several people say that we now need local rain to "clean the caves out". How does this work?

[jmaddox]

Ill take a crack at this one.

Local rain provides a source of water in the recharge area of the springs. This water then percolates through the fractured/porous/karst bedrock into the aquifer and "replaces" or dilutes the murky river water that entered the cave when the hydraulic head of the river exceeded the hydrostatic pressure of the aquifer/spring (reversal). I guess it blows out some of the silt too along with the divers and their scooters that can now enter the spring because they can see where they are going.

This may not be the most scientific or eloquent explanation and is most certianly over simplified, someone please correct me if Im wrong.

--jm

[Sludge]

River water is dirty; spring water is clean, filtered by the limestone. Rainwater seeps into the ground and becomes part of the aquifer. We want this clean water to push the dirty stuff out.

[Gary]

River water is dirty; spring water is clean, filtered by the limestone. Rainwater seeps into the ground and becomes part of the aquifer. We want this clean water to push the dirty stuff out.

River water rises fast? Drags lots of crap back into the caves, scoures off handprints and fin marks? burries gouges in tons of river debris? coats rocks in brown tanic once again?

Doesn't sound all bad.

Recharges the aquafer also - which will eventually come back out as clean spring water and restore flow to caves and passages that haven't had much pressure in a while.

But of course it is the clean spring water we are after to be swimmming in.