Overview
Soil and groundwater pollution is an ever increasing, worldwide problem. Tens of billions of dollars are spent each year in the United States and elsewhere to remediate groundwater pollution, and to limit or prevent future contamination of the subsurface. Most subsurface pollution problems stem from activities involving the unsaturated (vadose) zone between the soil surface and the groundwater table. The unsaturated zone hence provides the best opportunities to limit or prevent groundwater pollution. Once contaminants enter groundwater, pollution is essentially irreversible, or can be remediated only with extreme costs.
Numerical modeling is becoming an increasingly important tool for analyzing complex problems involving water flow and contaminant transport in the unsaturated zone. This workshop is designed to familiarize participants with the principles and numerical analysis of variably saturated flow and transport processes, and the application of state of the art numerical codes to site specific subsurface flow and transport problems.
The workshop begins with a detailed conceptual and mathematical description of water flow and solute transport processes in the vadose zone, followed by an overview of the use of finite element techniques for solving the governing flow and transport equations. Special attention is given to the highly nonlinear nature of the governing flow equation. Alternative methods for describing and modeling the hydraulic functions of unsaturated porous media are also described.
"Hands on" computer sessions will provide participants an opportunity to become familiar with the Windows based RETC, STANMOD, HYDRUS 1D, HYDRUS 2D and HYDRUS 3D software packages. Emphasis will be on the preparation of input data for a variety of applications, including flow and transport in a vadose zone, variably saturated flow through a dam, flow and transport to a tile drain, and two dimensional leachate migration from a landfill through the unsaturated zone into groundwater. Calibration will be discussed and demonstrated using both one and two dimensional model inversions.
Software
The workshop introduces a new generation of Windows based numerical models for simulating water flow and solute transport in the variably-saturated porous media. Three numerical models (HYDRUS-1D and HYDRUS-2D, and 3D for one-, two, and three-dimensional simulations, respectively) will be available during the workshop. Both models are supported by interactive graphics-based interfaces for data-preprocessing, generation of unstructured as well as structured finite element grid systems, and graphic presentation of the simulation results. The Windows-based versions of the RETC (for quantifying the hydraulic functions of unsaturated soils) and STANMOD (for evaluating solute transport in the subsurface using analytical solutions of the convection-dispersion equation) codes will also be demonstrated in the workshop. The RETC code will be provided to all participants.
Instructors
Dr. Martinus Th. van Genuchten is a soil physicist with the U. S. Salinity Laboratory, USDA, ARS, Riverside, CA. He received a B.S. and M.S. in irrigation and drainage from the Agricultural University of Wageningen, The Netherlands, and a Ph.D. in soil physics from New Mexico State University. He has published widely on variably-saturated flow and contaminant transport processes in the subsurface, analytical and numerical modeling, nonequilibrium transport, preferential flow, characterization and measurement of the unsaturated hydraulic functions, and root-water uptake.
Dr. Jirka Simunek is a research hydrologist with the Department of Soil and Environmental Sciences of the University of California. He received an M.S. in Civil Engineering from the Czech Technical University, Prague, Czech Republic, and a Ph.D. in Water Management from the Czech Academy of Sciences, Prague. His expertise is in numerical modeling of subsurface water flow and solute transport processes, equilibrium and nonequilibrium chemical transport, multicomponent major ion chemistry, field-scale spatial variability, and inverse procedures for estimating the hydraulic properties of unsaturated porous media.
Agenda
Workshop handouts include lecture notes prepared by the instructors, documentation of the RETC code (including the software), and documentation of the HYDRUS 1D, HYDRUS 2D and HYDRUS 3D numerical models.
Day 1
- Lecture 1: Conceptual and mathematical description of variably-saturated water flow and solute transport processes, root-water uptake, nonequilibrium transport, decay chains, initial conditions, boundary conditions;
- Lecture 2. Analytical modeling of solute transport in the subsurface, equilibrium and nonequilibrium transport models, parameter estimation.
- Computer session 1: Modeling subsurface solute transport using the STANMOD code; direct and inverse applications.
- Lecture 3: Review of the hydraulic properties of unsaturated porous media; measurement, description, parameter estimation.
- Computer session 2: Analyzing/estimating hydraulic properties with the RETC and Rosetta codes.
- Lecture 4: Review of numerical methods for solving the variably-saturated water flow and solute transport equations; Application of finite element method to 1D flow and transport; The HYDRUS-1D software package - model structure and examples.
- Computer session 3: Application of HYDRUS-1D to simple one-dimensional problems.
- Lecture 5: Inverse modeling; application of HYDRUS-1D to laboratory and field experiments.
- Computer session 4: Advanced one-dimensional forward and inverse problems with HYDRUS-1D.
Day 2
- Lecture 6: Application of finite element method to
2D variably-saturated water flow and solute
transport; The HYDRUS-2D software package - model structure, examples; Pre-and postprocessing
with HYDRUS-2D using the finite element mesh generator. - Computer session 5: Application of HYDRUS-2D to simple one-dimensional problem.
- Computer session 6: Application of HYDRUS-2D to simple two-dimensional problem.
- Lecture 7: Modeling water flow and solute transport in 3D; The HYDRUS-3D software package - model structure, examples; Pre-and post-processing with HYDRUS-3D will be discussed.
- Computer session 7: Application of HYDRUS-3D to simple three-dimensional problem.
- Computer session 8: Application of HYDRUS-3D to complex three-dimensional problem.
- General session: Other applications; discussion
Upon request, the Colorado School of Mines will award 1.3 Continuing Education Units (CEU) for completion of the workshop.
Registration fees: $ 450.00 before October 15 and $500.00 After October 15.
Housing in Waikiki : Room rates: $77.00 Deluxe Hotel Room and $84.00 for Ocean View Hotel Room.
University of Hawai`i Support Team
Ali Fares
Associate Professor of Hydrology
Natural Resources & Environmental Management Dept.
Office: Sherman 242-244
Phone: (808) 956-6361
Fax: (808) 956-6539
Email: afares@hawaii.edu
http://www.ctahr.hawaii.edu/faresa/
Aly El-Kadi, Associate Professor of Hydrology & Assistant Director of WRRC
Department of Geology and Geophysics and Water Resources Research Center (WRRC)
University of Hawaii at Manoa, Honolulu
POST Building, Room 709 Phone: (808) 956-6331 Fax: (808) 956-5512
Email: elkadi@Hawaii.edu
