HR: 0800h
AN: H11F-0345    [Abstracts]
TI: Storage-Dependent Drainable Porosity Implemented in the Hillslope-Storage Boussinesq Model: An application to Field Data From a Site in Northern Idaho, USA.
AU: * Hilberts, A
EM: arno.hilberts@wur.nl
AF: Hydrology and Quantative Water Management Group Wageningen University, Nieuwe Kanaal 11, Wageningen, 6709 PA Netherlands
AU: Troch, P
EM: peter.troch@wur.nl
AF: Hydrology and Quantative Water Management Group Wageningen University, Nieuwe Kanaal 11, Wageningen, 6709 PA Netherlands
AU: Boll, J
EM: jboll@uidaho.edu
AF: Department of Biological and Agricultural Engineering University of Idaho, Moscow Campus-JML 81B , Moscow, Id 83844-2060 United States
AU: Brooks, E
EM: broo2789@uidaho.edu
AF: Department of Biological and Agricultural Engineering University of Idaho, Moscow Campus-JML 81B , Moscow, Id 83844-2060 United States
AB: Specific yield is a parameter used to quantify the available amount of water for drainage. The instantaneous release of water from the aquifer during drainage however is determined by a related parameter, viz drainable porosity. In this work we present an analytical expression for drainable porosity as a function of water table depth and soil hydraulic parameters. This expression allows us to extend the hillslope-storage Boussinesq equation, recently introduced by the authors, to account for some of the effects of the unsaturated zone on dynamic hydrological behavior during free drainage from complex hillslopes. The concept of a storage-dependent drainable porosity is evaluated by comparing simulation results to field data, which were obtained from a site in Troy, Idaho, where a shallow silt loam soil layer is overlying a fragipan. Evaluation of the model is based on measurements of water table height, soil moisture and outflow. The field site is characterized by the influence of macropores, a decreasing saturated hydraulic conductivity with depth, and a small drainable porosity. Modeling of these data involved making the saturated hydraulic conductivity a function of the depth to the water table, and allowing for variable precipitation inputs.
DE: 1719 Hydrology
DE: 1829 Groundwater hydrology
DE: 1832 Groundwater transport
DE: 1860 Runoff and streamflow
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting