Groundwater Flow Modeling

Groundwater Flow Modeling GEOL 650 – Fall 2006 Dr. Dirk Baron Office: Science II, Room 333 Tel: (661) 654-3044; e-mail: [email protected] Office Hours: Wednesday 1-2 p.m.; or by prior arrangement Class Times and Location Tuesday and Thursday, 6:00 – 9:30 p.m. 1½ - 2 hour lecture followed by lab. Science Building II, Room 278. Required Textbooks Anderson and Woessner, Applied Groundwater Modeling, 1992, Academic Press. Selected sections of the following which can all be downloaded as pdf files from the USGS website: McDonald and Harbaugh, 1988, A modular three-dimensional finite difference ground-water flow model: U.S. Geological Survey Water Resources Investigations, Book 6, Ch. A1, 586 p. Harbaugh, A.W., Banta, E.R., Hill, M.C., and McDonald, M.G., 2000, MODFLOW-2000, the U.S. Geological Survey modular ground-water model -- User guide to modularization concepts and the Ground-Water Flow Process: U.S. Geological Survey Open-File Report 0-92, 121 p. Harbaugh, A.W., and McDonald, M.G., 1996, User's documentation for MODFLOW-96, an update to the U.S. Geological Survey modular finite-difference ground-water flow model: U.S. Geological Survey Open-File Report 96-485, 56 p. Konikow, L.F., Goode, D.J., and Hornberger, G.Z., 1996, A three-dimensional method-ofcharacteristics solute-transport model (MOC3D): U.S. Geological Survey WaterResources Investigations Report 96-4267, 87 p. Course Summary This class focuses on the use of computer models to describe the flow of groundwater and dissolved contaminants through the subsurface. Such numerical modeling is commonly used in water resources investigations and groundwater contamination studies. Computer modeling has thus become one of the key skills of hydrogeologists and civil engineers. Lecture topics include (1) a brief review of the equations that describe the flow of groundwater and contaminants, (2) an introduction to finite difference methods for the solution of differential equations, (3) an overview of modeling issues such as initial and boundary conditions, calibration, and verification, and (4) a discussion of currently used groundwater modeling software. The lab portion of the class consists of the modeling of increasingly complex groundwater flow and contamination problems using the spreadsheet program Excel, the groundwater modeling programs MODFLOW, MF2K-GWT, MOC3D; as well as Visual Modflow, a commercial graphical user interface for MODFLOW.

MODFLOW, MF2K-GWT, and MOC3D are public domain software developed by the U.S. Geological Survey and written in FORTRAN. MODFLOW employs finite difference methods for the solution of flow and transport equations and is by far the most commonly used groundwater modeling program. MF2K-GWT and MCO3D use particle tracking to simulate the transport of contaminants in groundwater. The lab problems include realistic groundwater flow scenarios with multiple aquifers, wells, recharge, and surface water - groundwater interactions, and a scenario involving the transport of dissolved contaminants from a landfill. Grading The course grade will be based on one exam, the lab exercises, and a presentation to the class. The lab exercises and reports are generally due one week after they are assigned. Please make prior arrangements for credit on missed or late labs. The exam and the lab exercises will each count for 40%, the class project for 15%, and the class presentation for 5% of the grade. Important Dates September 12. First day of classes October 2. Last day to withdraw without a “W” being recorded October 26. Midterm Exam October 30. Last day to withdraw for a serious and compelling reason November 16. Last class

Tentative Lecture Schedule

Week Topics

Readings

1

Class overview; Introduction to principles of flow modeling. Review of equations describing groundwater flow and contaminant transport;

Ch. 1, 2

2

Solution of partial differential equations with finite difference techniques. Introduction to Modflow.

3

Formulation of a conceptual model; Steady state versus transient simulations; Grid design.

Ch. 3, 7

4

Boundaries; Sources and sinks.

Ch. 4, 5

5

Model set-up and execution; Parameter selection.

6

The calibration process

7

Review midterm Midterm Exam, Thursday, October 26;

8

Modeling contaminant transport with particle tracking (MF2KGWT)

Ch. 11

9

Intro to Visual Modflow; Documentation and modeling reports. Thursday November 9; Guest Speaker David Bean, Geomatrix

Ch. 9

10

Advanced topics; Student presentations Last class on Monday, November 16; Course review; Discussion.

Ch. 12

Tentative Lab Schedule Lab 1. Finite-difference calculations by hand Lab 2. Finite Difference Modeling with a spreadsheet program Lab 3. Download and installation of MODFLOW and documentation Lab 4. Steady-state flow simulation with MODFLOW Lab 5. Recharge, River, and Drain Modules, Introduction to sensitivity analysis Lab 6. Transient flow simulation with MODFLOW, River, Well, and Drain Modules Lab 7. Transport modeling using MF2K-GWT (updated version of MOC3D) Lab 7. Introduction to Visual MODFLOW

Ch. 8