Contaminant Transport to Deep Wells

The process of convective transport of a conservative contaminant to a deep partially screened pumping well overlain by a zone of contaminated water is described by analytical and numerical techniques. The three-dimensional flow to the well is treated as a point sink in an anisotropic medium. The effects of a regional downward flow, a phreatic surface above the well, and an impervious lower boundary are evaluated. The theoretical results are compared with the observed nitrate contamination of wells on Long Island, New York. It is shown that the local convective transport produced due to pumping greatly accelerates the process of contamination and decontamination of the wells.