Timothy Callahan

College of Charleston

Upper-level undergraduate/first-year M.S.-level hydrogeology course

Basic theory of groundwater flow, in this case for unconfined aquifers (Dupuit approximation); knowledge of boundary conditions concepts. Basic knowledge of computer spreadsheet programs.

This can be assigned as a multiple-week project (capstone experience) or a stand-alone lab exercise. I present this as a two-part assignment; Part 1 requires the students to use a computer spreadsheet program (e.g., Microsoft EXCEL) to solve the problem, and then in Part 2 they are introduced to Visual-MODFLOW (Waterloo Hydrogeologic, Inc.). Students use their results from Part 1 while becoming familiar with MODFLOW.

Groundwater modeling; become familiar with the computer software package Visual-MODFLOW; produce groundwater flow maps and cross-sections based on field data and model results; study the effects of using different boundary conditions on groundwater flow; learn basic model calibration concepts and practices; study the effects of pumping wells on groundwater flow patterns.

Students are able to see the application of governing equations and boundary conditions on a "real" aquifer system (an idealized or an actual field site). The students also interpret the data and compile it into a consultant-style report, including recommendations on site management based on model simulation results.

Data interpretation; report writing

Students are trained to use the Visual MODFLOW computer program (Waterloo Hydrogeologic, Inc.) and they learn first-hand how to apply the Dupuit Approximation to groundwater flow and transport problems in unconfined aquifers. The students apply the Dupuit Approximation (Fetter, 2001) to a case study developed from Anderson and Woessner (1992) in which they are given system dimensions, aquifer properties, and well water levels. Learning objectives include (1) prediction of groundwater flow and transport and (2) model calibration (e.g., getting the model output to match well water level data). Students also learn how to solve the equations using a computer spreadsheet program, further expanding their ability to understand and work with the equations.

The students produce one (or two) complete lab report(s) that require creation and interpretation of Visual-MODFLOW simulation results in the form of maps and cross-sections for each simulation scenario. Students also compile their results in tabular form in order to compare the results for all scenarios. Students can also be asked to take note of calibration tolerances between model simulation and given water level data and/or conduct a sensitivity analysis of the groundwater model. Grading metrics for the report include thoroughness and quality of data interpretation; clarity of recommendations based on simulation results; and quality of writing.

Anderson, M.P. and W.W. Woessner. 1992. Applied Groundwater Modeling: Simulation of Flow and Advective Transport. Academic Press, Inc. San Diego, CA. pp. 143-145.
Fetter, C.W. 2001. Applied Hydrogeology. Prentice-Hall, Inc. Upper Saddle River, NJ.
Visual MODFLOW software and documentation