AN ASYMPTOTIC METHOD FOR PREDICTING THE CONTAMINATION OF A PUMPING WELL

A method is presented for predicting the advective-dispersive transpor t of a contaminant towards a well in a confined aquifer. Due to (macro -)dispersion, particles carry out random walks through the porous form ation, Using perturbation techniques analytical approximations are der ived for the fraction of the particles that reach the well and for the mean and variance of the arrival time. In particular, approximations for the breakthrough curve at the well are provided. The asymptotic ap proximations are shown to be in good agreement with results of random- walk simulations. The method may be applied to any 2D-flow pattern.