Perhaps the greatest risk posed by a combination of
uncontrolled ingress to the pit, direct access to the water table, and the "gravel
pit mentality" which an open borrow pit conveys, is the possibility that accidental
or intentional releases of hazardous material to the aquifer can occur. This photo is from
a demonstration conducted in November, 1999 using empty plastic drums; it was intended to
convey the ease with which a large quantity of material could be brought into the pit and
disposed directly to the water table.