How To Determine Depth By Dropping A Rock. To determine the depth (d) of the well you drop a rock from the top of the well and listen for the splash as the water hits the water’s surface. The sound of the splash arrives t = 3.8 s after you drop the rock.
Do not ignore the time for sound to travel back up to your ear. You stand at the top of a deep well. There is no known way of directly measuring permeability using remote sensing.
