Water wells aren't actually holes in the ground. Water wells are where a pipe is drilled into the ground until it connects with a water stream (usually 80-220 feet, depending on elevation). Septic tanks have a 3' diameter lid/cover. If anything other than sewage (such as bleach, or people) is put into the tank, it will result in system failure.
A slough is water that sits on the surface of the ground in a basin. Water levels vary annually. I wonder how deep the slough is. I suspect that "dragging" it would result in churning the mud and grass. I wonder if they'll do a visual inspection and use poles to detect anything at the bottom of the slough.
