HR: 0800h
AN: H51F-0847    [Abstracts]
TI: Hydraulic Conductivity Anisotropy of Unsaturated Soils
AU: * Zhu, J
EM: Jianting.Zhu@dri.edu
AF: Desert Research Institute, 755 E Flamingo Road, Las Vegas, NV 89119, United States
AU: Sun, D
EM: sundon@uhcl.edu
AF: University of Houston-Clear Lake, Environmental Science Program 2700 Bay Area Blvd, Houston, TX 77058, United States
AU: Neelakrishnan, S
AF: Desert Research Institute, 755 E Flamingo Road, Las Vegas, NV 89119, United States
AB: The effects of saturation degree (or tension) on hydraulic conductivity anisotropy in unsaturated soils have been recognized for long time, but they have not been fully described conceptually. Previous models include quantifying saturation-dependent anisotropy of soil formations that consist of many thin layers each with its own hydraulic properties characterized by a uniform density distribution of saturated hydraulic conductivity or soil bulk density. Some other approaches have also been developed to study the soil anisotropy behavior in dealing with flow and transport problems in saturated and unsaturated soils, such as tensorial connectivity-tortuosity concept. In this study, we investigate soil unsaturated hydraulic conductivity anisotropy that mainly arises from a combination of both wide range of soil texture variations and within narrow range of texture units in conjunction with pedotransfer functions (PTFs) of soil hydraulic properties. PTFs are often used to estimate soil hydraulic properties because direct measurements are too expensive and difficult. PTFs transform basic soil properties such as texture, bulk density into water retention and saturated or unsaturated hydraulic conductivity. We develop a new approach to combine the neural network based PTF results with the thin layer approach to explore saturation-dependent anisotropy behavior for a wide range of texture and bulk density conditions. Anisotropy models are developed that quantify saturated and unsaturated hydraulic conductivities for soils composed of many thin layers distinguished by texture, organic carbon content and bulk density.
DE: 1829 Groundwater hydrology
DE: 1839 Hydrologic scaling
DE: 1865 Soils (0486)
DE: 1875 Vadose zone
SC: Hydrology [H]
MN: 2007 Fall Meeting