AN EXTENDED TRANSFER-FUNCTION MODEL OF FIELD-SCALE SOLUTE TRANSPORT -MODEL DEVELOPMENT

Commonly used one-dimensional models for predicting solute transport i n the field are based on either a deterministic convection-dispersion equation or a stochastic-convective principle. These models, however, are limited to describing solute transport characterized by either a l inear or a quadratic increase in the travel time variance with depth i n a steady-state flow held. Based on an existing transfer function mod el, we propose a solute transport model in which the travel time varia nce increases proportionally with depth to the power 2a, where a is an adjustable constant representing the degree of horizontal solute mixi ng. The model based on the deterministic convection-dispersion equatio n is well approximated by the proposed model for a = 0.5, while the mo del based on a stochastic-convective principle is a special case of ou r model for a = 1. Effects of different a values on solute transport a nd relevant problems are briefly discussed.