A SIMPLE NUMERICAL SOLUTION FOR THE VERTICAL FLOW EQUATION OF WATER THROUGH UNSATURATED SOILS

Abstract

We present a simple numerical method to solve the vertical flow equation of water through unsaturated soils. The method is based on the approximation K = Ko·eaψ and can be used for any range of soil moisture. The method uses the behavior of the exponential function in an integrated flux formula. The resulting numerical scheme is extremely easy to program and runs about as fast on microcomputers as implicit techniques do on large computers. Mass conservation is also excellent. We present a simple numerical method to solve the vertical flow equation of water through unsaturated soils. The method is based on the approximation K = Ko·eaψ and can be used for any range of soil moisture. The method uses the behavior of the exponential function in an integrated flux formula. The resulting numerical scheme is extremely easy to program and runs about as fast on microcomputers as implicit techniques do on large computers. Mass conservation is also excellent. © Williams & Wilkins 1980. All Rights Reserved.