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.