'A Civil Action' 1-D Transport Game

Scott Bair
,
Ohio State University
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Summary

The 'A Civil Action' 1-D Transport Game is executed in an EXCEL spreadsheet and is designed to help students learn why models are used by scientists and engineers and what procedures must be met to construct a predictive model by simulating the transport of TCE from W.R. Grace to the area of municipal wells G and H. The lure to students is that these concepts are presented within the context of the famous 'A Civil Action' trial. The assignment compares the development of a predictive groundwater model with the steps involved in the scientific method and with the path of a lawsuit through the U.S. court system.

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Context

Audience

The exercise is appropriate for undergraduates in a first hydrogeology course because the mechanics behind the numerical solution of the advection-dispersion equation can be ignored. Input to the spreadsheet consists solely of K values, b values, and recharge rates. The spreadsheet automatically calculates flow velocities and traveltimes and creates concentration break-through graphs and graphs of contaminant velocity versus distance. The catch is that the spreadsheet automatically compares simulated heads and streamflow gains/losses to those measured by the USGS in 1985 and 1986 just before the famous trial. Thus, students run the spreadsheet several times to try to minimize these differences. An aerial photograph, geologic cross section, and other images of the glacial sediments in the valley are contained in the WORD file.

Skills and concepts that students must have mastered

Darcy velocity, geologic map interpretation, regional flow, ranges of K, recharge and infiltration rates, heterogeneity, advective transport, contaminant transport with retardation, stream discharge measurement.

How the activity is situated in the course

I use this activity as a lab in the 9th week of my 10-week hydrogeology course. I use 'A Civil Action' as a poignant example of how contaminant hydrogeology is important to society problems. I show parts of the movie is class before distributing the assignment and read excerpts from the 'A Civil Action' book. In our PC lab, I also demonstrate to students how the spreadsheet works and how the iterative solver in EXCEL is actuated (details are given in the write up).

Goals

Content/concepts goals for this activity

The goals are to show students that not all models are created equal, that different types of models are used for different purposes, that two experts using an identical database can reach different conclusions, and that predictive models require matching to measured data, which differentiates tested and accepted scientific theory from untested dogma.

Higher order thinking skills goals for this activity

The students have to interpret a geologic cross section, assign reasonable values of K and n to different geologic materials, assess whether the simulated heads and velocities are realistic, and critically evaluate their results with the testimony of the two expert witnesses testifying (competing) with different conceptualizations and models in the famous trial.

Other skills goals for this activity

It is a wonderful platform from which to get students to talk about their impressions of the U.S. court system, to see whether they think the goal of a trial is to find "truth" or to seek a solution to a dispute, and to see how science and society interact.

Description of the activity/assignment

The 'A Civil Action' 1-D Contaminant Transport Game is an EXCEL spreadsheet that enables students to compute concentrations of TCE traveling in the groundwater flow system toward well H that emanate from the W.R. Grace site. The idea of the game is to draw students into learning some of the fundamental concepts about (1) how contaminants move in the subsurface and (2) how models can be used to test hypotheses. These concepts are taught within the context of the famous 'A Civil Action' trial described in the book by Jonathan Harr (1996) and the movie starring John Travolta (1998).

The spreadsheet computes values of hydraulic head, advective flow velocities and traveltimes, contaminant velocities, and contaminant concentrations at 20 locations along the flowpath from W.R. Grace to the Aberjona River. Breakthrough curves showing changes in concentration versus distance and changes in concentration versus time pop-up automatically (see below). The spreadsheet also creates graphs of advective and contaminant velocities versus distance.

Determining whether students have met the goals

This is determined by the graphs that students print out using the EXCEL spreadsheet, through reading their responses to a group of questions, and from classroom discussion of the role of science in society.

More information about assessment tools and techniques.

Teaching materials and tips

Other Materials

Supporting references/URLs

Bair, E.S., and M.A. Metheny, 2002. Remediation of the Wells G & H Superfund Site, Woburn, Massachusetts, Ground Water, vol. 40, no 6, p. 657-668.

Bair, E.S., 2001, Models in the Courtroom, Chapter 5, in Model Validation, Perspectives in Hydrological Science, M.G. Anderson and P.D. Bates, eds., John W. Wiley & Sons Ltd., West Sussex, England, 57-76.

Harr, J., 1995, "A Civil Action," Random House, New York, 500 p.

M.A. Metheny, 2004, "Evaluation of Groundwater Flow and Contaminant Transport at the Wells G & H Superfund Site, Woburn, Massachusetts, from 1960 to 1986 and Estimation of TCE and PCE Concentrations Delivered to Woburn Residences," Ph.D. dissertation, Department of Geological Sciences, The Ohio State University, 346 pp.

M.A. Metheny, 1998, "Numerical Simulation of Groundwater Flow and Advective Transport at Woburn, Massachusetts, Based on a Sedimentological Model of Glacial and Glaciofluvial Deposition," M.S. thesis, Department of Geological Sciences, The Ohio State University, 197 pp.

Metheny, M.A., and E.S. Bair, 2001. The Science Behind A Civil Action—The Hydrogeology of the Aberjona River, Wetland and Woburn Wells G and H, West, D.P. and R.H. Bailey, eds., in Guidebook for the Geological Field Trips in New England, 2001 Annual Meeting of the Geological Society of America, p. D1-D25, Boston, Massachusetts.

Metheny, M.A., E.S. Bair, and D.K. Solomon, 2001. Applying variable recharge to a 19-year simulation of groundwater flow in Woburn, Massachusetts and comparing model results to 3H/3He ages, Seo, H.S., E. Poeter, C. Zheng, and O. Poeter, eds., in MODFLOW 2001 and Other Modeling Odysseys—Conference Proceedings, vol. 2, p. 783-789, International Ground Water Modeling Center, Colorado School of Mines, Golden, Colorado.

Myette, C.F., J.C. Olympio, and D.G. Johnson, 1987, Area of influence and zone of contribution to Superfund-site Wells G and H, Woburn, Massachusetts; U. S. Geological Survey, Water-Resources

Science in the Courtroom www.geology.ohio-state.edu/courtroom