HR: 0800h
AN: H51F-0843    [Abstracts]
TI: Effective Hydraulic Properties for Transient Flow in Unsaturated Zone
AU: * Sun, D
EM: sundon@uhcl.edu
AF: University of Houston, Clear Lake, Environmental Science Program 2700 Bay Area BLVD, Box #39, Houston, TX 77058,
AU: Zhu, J
EM: jianting.zhu@dri.edu
AF: Desert Research Institute, Division of Hydrological Sciences 755 E Flamingo Road, Las Vegas, NV 89119,
AB: Unsaturated zone plays important role in many hydrological and environmental processes. Deriving average/effective parameters is essential for many large scale hydrological, environmental or climate studies. Upscaling is a process of using local-scale hydraulic properties to derive effective properties representing a large scale. In this study, we investigate: 1) how the hydrologic processes impact on the effective hydraulic properties; 2) how the effective hydraulic properties schemes are sensitive to the initial conditions; and 3) how the effective hydraulic properties are related to boundary conditions for heterogeneous soils. The main idea is whether the interested process behavior in heterogeneous soils can be captured by a process that assumes only one set of soil parameters, such that the heterogeneous system is replaced by an equivalent homogeneous system. By using field and re-generated hydraulic data sets, this study derives effective hydraulic properties under transient flow conditions. Precipitation, evaporation, and root water uptake and their effects on the effective properties are also considered during the simulations. An inverse procedure is used to determine the effective hydraulic parameters various flow scenarios. Results show that effective hydraulic parameters change with time scale initially, and then approach nearly constant values, indicating an equivalent homogeneous medium is a more viable alternative for large spatial and temporal scale transient infiltration process. Keywords: Upscaling, Transient Flow, Effective Parameters, Heterogeneous Soil
DE: 1836 Hydrological cycles and budgets (1218, 1655)
DE: 1838 Infiltration
DE: 1875 Vadose zone
SC: Hydrology [H]
MN: 2007 Fall Meeting