AN ANALYTICAL SOLUTION FOR PREDICTING SOLUTE TRANSPORT DURING PONDED INFILTRATION

An analytical solution is presented for one-dimensional solute transpo rt in soil during ponded infiltration. The pore-water velocity v = q/t heta in the convection-dispersion transport equation was obtained by a ssuming that the water flux density a in the soil can be calculated wi th the Green-Ampt infiltration model, q = a + b/I, in which a and b ar e constants and I is the cumulative infiltration rate evaluated using Philip's two-term infiltration equation. The water content theta was a pproximated by the saturated water content, theta(s). Through an appro priate transformation, the solute transport equation for transient uns aturated flow conditions was linearized and solved analytically for a general initial concentration profile given by an arbitrary number of straight line segments. The solution compared well with more complete numerical solutions of the transport problem, as well as with several experimental data sets.