Tracing Parcels of Water and Solutes in Unsaturated Zones

摘要: Convection with water is the chief mechanism for transport of solutes in unsaturated zone. The fate parcels rather homogeneous media, subject to boundary conditions can be determined on basis traditional theory, and such an approach considered first part this chapter. It yields good estimates patterns penetration distributions travel times solutes. Unfortunately, practice, numerous factors may complicate flow patterns, generally leading more erratic wider times. Among these are (1) spatial variability physical properties conditions; (2) coarse structure due aggregates, cracks, channels; (3) secondary flows density gradients liquid phase instability wetting fronts. Implications discussed by Dagan Bresler (Chap. 2). influences second