SOLUTE TRANSPORT THROUGH CONFINED AQUIFER

Abstract

Contaminants are being increasingly added to groundwater aquifers through various human activities and natural processes. The movement of contaminants, in subsurface region, from a source is due to convective and dispersive mode. Convection is due to natural/forced movement of groundwater whereas dispersion is due to the concentration gradient present in space. The present work deals with the development of a numerical model for two-dimensional axisymmetric transient radial transport of pollutant from a recharge well for known velocity distribution in space and time. Finite element method has been used for numerical solution of transport equation. The finite element program developed in FORTRAN - 77 incorporates numerically integrated 8-noded rectangular serendipity element. The program is checked for purely convective transport and combined convection and dispersion cases. The results were found to deviate from the corresponding analytical solution. This deviation could be due to errors on account of inappropriate discretisation of flow domain. in the present study, the space and time were discretised in accordance with the recommendations in respect of transient radial flow, as given by Rushton.