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Using a Fractal Model to Compute the Hydraulic Conductivity Function
Author(s) -
Shepard J. Scott
Publication year - 1993
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1993.03615995005700020002x
Subject(s) - hydraulic conductivity , fractal , function (biology) , statistical physics , conductivity , biological system , mathematics , soil science , environmental science , geology , mechanics , physics , mathematical analysis , biology , soil water , quantum mechanics , evolutionary biology
Because it is easier and faster to determine the soil water retention curve than the hydraulic conductivity function, it would be desirable to have a method for calculating the latter from the former. A physically based relationship between conductivity and retention would, if correct, shed light on the status and movement of water in the soil. A method for calculating the hydraulic conductivity of unsaturated soil from moisture retention data and a fractal description of soil water flow paths was derived. The fractal model was a triadic Koch curve with segment lengths equal to twice the capillary radius, which was equivalent to the matric potential of selected points on the retention curve. The total length of the water flow path at the different pressures was determined by the total length of the fractal curve. This means that the path length increases as the matric potential increases in magnitude. Published data were used to determine average measured retention curves and hydraulic conductivity functions for three soil types: sand, loam, and clay. The calculated hydraulic conductivities approximated the measured conductivities at all water contents for all soil types.