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Predicting vertically-nonsequential wetting patterns with a source-responsive model

Vadose Zone Journal

By:
,
DOI: 10.2136/vzj2013.03.0054

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Abstract

Water infiltrating into soil of natural structure often causes wetting patterns that do not develop in an orderly sequence. Because traditional unsaturated flow models represent a water advance that proceeds sequentially, they fail to predict irregular development of water distribution. In the source-responsive model, a diffuse domain (D) represents flow within soil matrix material following traditional formulations, and a source-responsive domain (S), characterized in terms of the capacity for preferential flow and its degree of activation, represents preferential flow as it responds to changing water-source conditions. In this paper we assume water undergoing rapid source-responsive transport at any particular time is of negligibly small volume; it becomes sensible at the time and depth where domain transfer occurs. A first-order transfer term represents abstraction from the S to the D domain which renders the water sensible. In tests with lab and field data, for some cases the model shows good quantitative agreement, and in all cases it captures the characteristic patterns of wetting that proceed nonsequentially in the vertical direction. In these tests we determined the values of the essential characterizing functions by inverse modeling. These functions relate directly to observable soil characteristics, rendering them amenable to evaluation and improvement through hydropedologic development.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Predicting vertically-nonsequential wetting patterns with a source-responsive model
Series title:
Vadose Zone Journal
DOI:
10.2136/vzj2013.03.0054
Volume
12
Issue:
4
Year Published:
2013
Language:
English
Publisher:
Soil Science Society of America
Contributing office(s):
National Research Program - Western Branch
Larger Work Type:
Article
Larger Work Subtype:
Journal Article