A Macroscopic Relationship for Preferential Flow in the Vadose Zone

Download or read book A Macroscopic Relationship for Preferential Flow in the Vadose Zone written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Preferential flow commonly observed in unsaturated soils allows rapid movement of solute from the ground surface or vadose zone to the groundwater, bypassing a significant volume of unsaturated soil and increasing the risk of groundwater contamination. A variety of evidence indicates that complex preferential flow patterns observed from fields are fractals. This paper discusses a macroscopic rela-tionship for modeling preferential flow in the vadose zone. Conceptually, the flow domain can be di-vided into active and inactive regions. Flow occurs preferentially in the active region (characterized by fractals), and inactive region is simply bypassed. The portion of the active region was found to be a power function of saturation. The validity of this macroscopic relationship is demonstrated by its consistency with field observations and the related numerical experiments.