Material coordinate formulation and use in one-dimensional soil solute andwater flow

Description of one-dimensional water now in saturated swelling soils is fac ilitated by using a space-like coordinate based on the distribution of soli ds; a water-based space-like coordinate facilitates analysis of solute move ment during non-steady water flow in unsaturated soils. These space-like ma terial coordinates are simply defined and measured for many practical situa tions. Furthermore, their mathematical formulations are similar and result in similar non-linear diffusion equations that may be solved for important initial and boundary conditions. The approach may be extended to solute tra nsport during non-steady flow of water in a swelling soil. This paper illus trates the similarity of methods of formulating now equations, it discusses the benefits of the use of such coordinates, and it comments on the need f or dimensional consistency between coordinates and intrinsic soil propertie s.