A video field trip into a karst aquifer

This video was recorded by the Virginia Department of Environmental Quality in a six-inch well drilled through Ordovician-age Knox Group limestone using a pan-and-tilt waterproof video camera on a wireline.

Hit the play button to go on a trip into the earth.

As you are lowered down the well, you can see your depth on the counter at the lower left.  The specks you see are passing are clumps of silt or clay suspended in the still water.  In this relatively old well, the formerly bare rock wells are coated with silt and probably organic slime.

At the 0:55 mark, you will enter a karst solution conduit.  You are in the plumbing system.  As the camera pans, you can see that this conduit extends beyond view in both directions.  This is the type of feature we are talking about; capable of rapidly transporting a lot of water - good if you need water, but bad if the water needs underground filtration or residence time to naturally remove contaminants or pathogens.

Hang in there until the 2:00 mark, and it gets slightly gruesome...

Apparently, several rodents have fallen down this well.

 

This picture is a still frame from our own video survey of another well, and it shows water jetting from a karst conduit into the well bore at a depth of 105 feet.