Wivell:
Regarding a spring continuing to seep when 5 feet deep...if there's enough "head" it will happen. Just like the description of putting in the black pipe...that's the defining question.
I've got a tile from a farm field that runs 400 yards and dumps into one of my ponds. We buried it under about 3 feet of clay, and that's under 5 feet of water. After a recent storm, I couldn't figure out what was causing the brown cloud in the water, until I realized that's where the tile ended...
It had enough pressure (head) from the terrace in the field to boil up through the clay and water. This was an abnormally heavy rainfall...it doesn't happen often. Elevation to that point though, is probably only about 12 feet.
In a lifetime, the average driver will honk 15,250 times. My wife figures I'm due to die any day now...
