Fractal processes in soil water retention

Journal Article · Tue May 01 04:00:00 EDT 1990 · Water Resources Research; (United States)

DOI:https://doi.org/10.1029/WR026i005p01047· OSTI ID:5454405

Tyler, S W; Wheatcraft, S W ^[1]

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1. Univ. of Nevada, Reno (USA)

The authors propose a physical conceptual model for soil texture and pore structure that is based on the concept of fractal geometry. The motivation for a fractal model of soil texture is that some particle size distributions in granular soils have already been shown to display self-similar scaling that is typical of fractal objects. Hence it is reasonable to expect that pore size distributions may also display fractal scaling properties. The paradigm that they used for the soil pore size distribution is the Sierpinski carpet, which is a fractal that contains self similar holes (or pores) over a wide range of scales. The authors evaluate the water retention properties of regular and random Sierpinski carpets and relate these properties directly to the Brooks and Corey (or Campbell) empirical water retention model. They relate the water retention curves directly to the fractal dimension of the Sierpinski carpet and show that the fractal dimension strongly controls the water retention properties of the Sierpinski carpet soil. Higher fractal dimensions are shown to mimic clay-type soils, with very slow dewatering characteristics and relatively low fractal dimensions are shown to mimic a sandy soil with relatively rapid dewatering characteristics. Their fractal model of soil water retention removes the empirical fitting parameters from the soil water retention models and provides paramters which are intrinsic to the nature of the fractal porous structure. The relative permeability functions of Burdine and Mualem are also shown to be fractal directly from fractal water retention results.

• DOE Contract Number: FG08-85NV10461
• OSTI ID: 5454405
• Journal Information: Water Resources Research; (United States), Journal Name: Water Resources Research; (United States) Vol. 26:5; ISSN 0043-1397; ISSN WRERA
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540210* -- Environment
Terrestrial-- Basic Studies-- (1990-)
540310 -- Environment
Aquatic-- Basic Studies-- (1990-)
GROUND WATER
HYDRAULIC CONDUCTIVITY
HYDROGEN COMPOUNDS
INTERSTITIAL WATER
MATHEMATICAL MODELS
OXYGEN COMPOUNDS
PARTICLE SIZE
PHYSICAL PROPERTIES
PORE PRESSURE
RETENTION
SIZE
SOILS
TEXTURE
WATER