HR: 1340h
AN: H33F-0534    [Abstracts]
TI: A Coupled Systems Approach to Solute Transport Within a Heterogeneous Vadose Zone-Groundwater Environment
AU: * Fisher, J C
EM: stormplot@gmail.com
AF: University of California, Los Angeles, UCLA/CEE Dept, 5731/5732 Boelter Hall Box 159310, Los Angeles, CA 90095 United States
AU: Harmon, T C
EM: tharmon@ucmerced.edu
AF: University of California, Merced, School of Engineering P.O. Box 2039, Merced, CA 95344 United States
AB: A coupled systems approach is presented for the simulation of fluid flow and solute transport within a heterogeneous vadose zone-groundwater environment. Separate model domains were developed for the vadose and saturated zones. The numerical model used is FEMWATER, a three-dimensional finite element model for simulating flow and transport in variably saturated media. A control plane, located at the spatial intersection of the model boundaries, couples the two systems together. The fluid flux and solute mass passing through the control plane during a vadose zone simulation is used to construct the recharge boundary condition in the saturated system. Coupling the two systems allows for the accurate representation of flow and transport within the vadose zone along with the ability to simulate regional plume migration in the saturated zone. The Recharge Boundary Construction Algorithm adaptively reconciles both the spatial and temporal discretization differences between the vadose zone and saturated zone models. The accuracy of the algorithm is determined by a set of user-defined parameters controlling the algorithm's adaptive spatial mesh and adaptive temporal time step routines. The routines are designed to capture the greatest resolution of spatial and temporal changes in fluid flux across the control plane during a vadose zone simulation. A sensitivity analysis performed on the control parameters for the construction of the recharge boundary shows the maximum percent difference in total mass passing through the control plane during a vadose zone simulation as having the greatest effect on the boundaries level of resolution. Numerical simulations are made investigating the impact of effluent recharge at the ground surface on the solute breakthroughs and distributions in the two systems.
DE: 1800 HYDROLOGY
DE: 1829 Groundwater hydrology
DE: 1832 Groundwater transport
DE: 1875 Unsaturated zone
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting