ABSTRACT Our team has developed a user-friendly software package, EnviroLand © , for teaching hydrological fate and transport concepts to undergraduate students. We have successfully used this program in introductory Earth science courses, environmental chemistry, geochemistry, and geohydrology. EnviroLand contains basic transport models for river, lake, and groundwater systems and can be used to simulate the transport of pollutants under a variety of conditions. A free copy of EnviroLand can be downloaded from http://www. edusolns.com/. Keywords: Education—computer assisted; hydrology and hydrogeology; teaching and curriculum. INTRODUCTION Since the mid-1990s the use of computer-assisted instruction has markedly increased in many areas, especially in the Earth sciences. One of the first concerted efforts to develop Earth science software was by the United Kingdom Earth Science Courseware Consortium (UKESCC), which was formed in 1992. The first releases from the UKESCC are summarized by Edwards et al. (1996) and contain computer applications for field exercises, mineralogy, developing map skills, and basic geology skills. Programming efforts can be divided into several categories, including the development of quantitative and qualitative skills. This literature review will focus on quantitative skills, which is the major emphasis of our software package, EnviroLand. Initial software approaches reported in the literature combine physical models which can then be followed by a spreadsheet analysis (de Wet, 1994; Werner and Roff, 1994; Matisoff, 1995; Lee, 1998; Rose, 1997). Other approaches are 1) web based (Berger, 1997; Saini-Eidukat, 1998), 2) based on numerical analysis (Baker et al., 1995; Barrows and Paul, 1998), 3) utilize STELLA ® simulations (de Wet, 1994; Levy and Mayer, 1999; Bice, 2001), 4) teach students contouring techniques (Busse, 1997; Hudak, 1996; Hudak, 1998), 5) allow the identification of minerals (Edwards et al., 1996; Murray and Yavine, 1998), 6) simulate seismic reflection (Kallio and Peltoniemi, 1995), 7) illustrate plate tectonics (Baker et al., 1995; Guth, 1997), 8) teach basin formation (Baker et al., 1995; Barrows and Paul, 1998), and 9) allow the visualization of ocean wave dynamics (Gould and Whitford, 2000). While many teachers may still question the effectiveness of computer-assisted instruction (CAI), one study suggests that CAI is equally or more effective than traditional teaching methods because it focuses student attention on fundamental principles and problem-solving skills (Renshaw et al., 1998). This article illustrates the use of a new software package, EnviroLand, for use in the undergraduate classroom. Internet tracking indicates that EnviroLand has already been downloaded to over 750 sites in over 17 countries. We have effectively used EnviroLand in Earth science, environmental chemistry, geochemistry, and hydrogeology courses. THE SOFTWARE: ENVIROLAND EnviroLand is the result of a four-year programming and testing effort conducted at Hartwick College (Oneonta, New York, USA) and Whitman College (Walla Walla, Washington, USA). The program was created by undergraduate students in geology, biology, and chemistry using Visual Basic® (Microsoft, Inc.). It contains five laboratory simulations for environmental chemistry, three theoretical calculations for quantitative analysis, geochemistry, and environmental chemistry, and seven hydrological fate and transport models for a variety of educational levels. Each module is fully interactive, user-friendly, and requires input (interaction) from the user. The fate and transport modules, the focus of this article, can be used in high school science classes, introductory college science courses, and undergraduate hydrology courses. EnviroLand works on personal computers (Windows 95 or later editions) and requires 34 MB of hard drive space. A free, self-extracting copy can be obtained at http://www.edusolns.com. After downloading the self-extracting file, open the EnviroLand folder in the Windows Temporary folder and double click on the .exe file to install EnviroLand on your computer. Nine examples of EnviroLand modules are shown in Table 1 and represent the fate and transport equations in their simplest form. Table 1 contains a description of each fate and transport module, the governing equation for each model, and an illustration of the output plot that is generated by EnviroLand. Each transport module contains 1) a background section explaining the Dunnivant et al. - Teaching Pollutant Fate and Transport Concepts 553 TEACHING POLLUTANT FATE AND TRANSPORT CONCEPTS TO UNDERGRADUATE NON-SCIENCE MAJORS, ENVIRONMENTAL SCIENTISTS, AND HYDROLOGISTS USING ENVIROLAND Frank M. Dunnivant Chemistry Department, Whitman College, Walla Walla, WA 99362 Dan Danowski Department of Geological Sciences, Cornell University, Ithaca, NY 14853 Meredith Newman Departments of Chemistry and Geology, Hartwick College, Oneonta, NY 13820
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ABSTRACT
Our team has developed a user-friendly softwarepackage, EnviroLand
©, for teaching hydrological fate
and transport concepts to undergraduate students. Wehave successfully used this program in introductoryEarth science courses, environmental chemistry,geochemistry, and geohydrology. EnviroLand containsbasic transport models for river, lake, and groundwatersystems and can be used to simulate the transport ofpollutants under a variety of conditions. A free copy ofEnviroLand can be downloaded from http://www.edusolns.com/.
Keywords: Education—computer assisted; hydrologyand hydrogeology; teaching and curriculum.
INTRODUCTION
Since the mid-1990s the use of computer-assistedinstruction has markedly increased in many areas,especially in the Earth sciences. One of the first concertedefforts to develop Earth science software was by theUnited Kingdom Earth Science Courseware Consortium(UKESCC), which was formed in 1992. The first releasesfrom the UKESCC are summarized by Edwards et al.(1996) and contain computer applications for fieldexercises, mineralogy, developing map skills, and basicgeology skills.
Programming efforts can be divided into severalcategories, including the development of quantitativeand qualitative skills. This literature review will focus onquantitative skills, which is the major emphasis of oursoftware package, EnviroLand. Initial softwareapproaches reported in the literature combine physicalmodels which can then be followed by a spreadsheetanalysis (de Wet, 1994; Werner and Roff, 1994; Matisoff,1995; Lee, 1998; Rose, 1997). Other approaches are 1) webbased (Berger, 1997; Saini-Eidukat, 1998), 2) based onnumerical analysis (Baker et al., 1995; Barrows and Paul,1998), 3) utilize STELLA® simulations (de Wet, 1994;Levy and Mayer, 1999; Bice, 2001), 4) teach studentscontouring techniques (Busse, 1997; Hudak, 1996;Hudak, 1998), 5) allow the identification of minerals(Edwards et al., 1996; Murray and Yavine, 1998), 6)simulate seismic reflection (Kallio and Peltoniemi, 1995),7) illustrate plate tectonics (Baker et al., 1995; Guth, 1997),8) teach basin formation (Baker et al., 1995; Barrows and
Paul, 1998), and 9) allow the visualization of ocean wavedynamics (Gould and Whitford, 2000). While manyteachers may still question the effectiveness ofcomputer-assisted instruction (CAI), one study suggeststhat CAI is equally or more effective than traditionalteaching methods because it focuses student attention onfundamental principles and problem-solving skills(Renshaw et al., 1998).
This article illustrates the use of a new softwarepackage, EnviroLand, for use in the undergraduateclassroom. Internet tracking indicates that EnviroLandhas already been downloaded to over 750 sites in over 17countries. We have effectively used EnviroLand in Earthscience, environmental chemistry, geochemistry, andhydrogeology courses.
THE SOFTWARE: ENVIROLAND
EnviroLand is the result of a four-year programming andtesting effort conducted at Hartwick College (Oneonta,New York, USA) and Whitman College (Walla Walla,Washington, USA). The program was created byundergraduate students in geology, biology, andchemistry using Visual Basic® (Microsoft, Inc.). Itcontains five laboratory simulations for environmentalchemistry, three theoretical calculations for quantitativeanalysis, geochemistry, and environmental chemistry,and seven hydrological fate and transport models for avariety of educational levels. Each module is fullyinteractive, user-friendly, and requires input(interaction) from the user. The fate and transportmodules, the focus of this article, can be used in highschool science classes, introductory college sciencecourses, and undergraduate hydrology courses.
EnviroLand works on personal computers(Windows 95 or later editions) and requires 34 MB ofhard drive space. A free, self-extracting copy can beobtained at http://www.edusolns.com. Afterdownloading the self-extracting file, open theEnviroLand folder in the Windows Temporary folderand double click on the .exe file to install EnviroLand onyour computer.
Nine examples of EnviroLand modules are shown inTable 1 and represent the fate and transport equations intheir simplest form. Table 1 contains a description ofeach fate and transport module, the governing equationfor each model, and an illustration of the output plot thatis generated by EnviroLand. Each transport modulecontains 1) a background section explaining the
Dunnivant et al. - Teaching Pollutant Fate and Transport Concepts 553
TEACHING POLLUTANT FATE AND TRANSPORT CONCEPTS TOUNDERGRADUATE NON-SCIENCE MAJORS, ENVIRONMENTALSCIENTISTS, AND HYDROLOGISTS USING ENVIROLAND
Frank M. Dunnivant Chemistry Department, Whitman College, Walla Walla, WA 99362
Dan Danowski Department of Geological Sciences, Cornell University, Ithaca, NY 14853
Meredith Newman Departments of Chemistry and Geology, Hartwick College, Oneonta, NY 13820
derivation and application of the equations, 2) how theequations can be used in fate and transport calculations,3) various conversion and data tables, 4) a detailedexample of how the calculations can be made by hand,and 5) additional problems that can be solved usingEnviroLand. The parameter values from the backgroundexample can be automatically uploaded into the modelfor beginners.
Each module is designed to predict the concentrationof pollutants at varying times and distances from thesource for students that are not familiar with modeling,and in most cases, for students that are not highly skilledin mathematics. First, a distinction between a step inputand an instantaneous (or pulse) input should be made. Astep input remains constant with time; once the inputbegins it continues indefinitely. Typical step inputs ofpollutants occur when a new industrial process is startedup, during deep well waste disposal in aquifers, or whena landfill begins to leak into an aquatic system.
An instantaneous or pulse input is a pollutant releasewhere the source is temporary and occurs as a singleevent. Examples of instantaneous inputs include thederailment of a tanker car into a stream, an accidentalindustrial release, the illegal “mid-night disposal” ofwaste into a stream or lake, or a spill of a liquid pollutanton the ground (with subsequent migration to the surface
aquifer). Most releases can be characterized as step orinstantaneous inputs and EnviroLand can be used topredict the down-stream or down-gradient pollutantconcentration in these aquatic systems. Each equationaccounts for biological or chemical degradation as afirst-order process. The river and ground water modulesaccount for dispersion and mixing. In addition, theground water modules account for linear sorption of thecontaminant to subsurface material. All modules willaccept variable input conditions such as flow rates,stream and ground water velocities, mass loading of thepollutant, water volume, dispersion, degradation rates,and sorptive retardation.
The Modules - The first two plots in Table 1 illustratepollutant transport in lakes. The instantaneous inputmodel assumes a complete and instantaneous mixing ofthe lake to obtain the initial pollutant concentration.After the initial mixing, the pollutant is removed fromthe lake through its effluent stream and/or bydegradation. The net result of these processes is anexponential decrease in the pollutant concentration overtime, with the overall depletion rate determined mostlyby the detention time in the lake (or possibly by thedegradation rate constant, k). A step input of a pollutantto a similar system (the second plot in Table 1) shows a
554 Journal of Geoscience Education, v. 50, n. 5, November, 2002, p. 553-558
Figure 1. Conceptualization of the Factors Governing the Transport of Pollutants in a Stream.
Dunnivant et al. - Teaching Pollutant Fate and Transport Concepts 555
slow increase in pollutant concentration (due to aconstant input of pollutant) which eventually reaches aplateau or steady-state concentration governed by thedegradation rate, the input rate of pollutant, and theremoval rate of pollutants in the lake effluent.
The stream fate and transport modules are shown inthe third through the fifth plots in Table 1. Twoinstantaneous inputs are illustrated, one where thepollutant is predicted at a fixed time and varyingdistance downstream, and another where the distancedownstream is fixed (e.g. when the observer is standingon a bridge) and the pollutant concentration is predictedas a function of time. The fifth plot in Table 1 illustratesthe result of a step release of pollutant to a stream. Thepollutant release is most concentrated immediatelyadjacent to the source, and due to mixing anddegradation, the pollutant profile exponentiallydecreases with time or distance downstream.
The last four sections of Table 1 illustrate the use ofthe one-dimensional fate and transport ground watermodules in EnviroLand. Two plots (plots 6 and 7) on aninstantaneous release are illustrated by the bell-shapednature of the pollutant profile with varying distance ortime. The two step releases (plots 8 and 9) show that thepollutant concentration increases (or decreases) to asteady-state concentration as a function of time (for afixed observation distance, x) or as a function of distance(for a fixed time).
USE OF ENVIROLAND IN THECLASSROOM
For Non-science Majors: One of the most chal- lengingand rewarding applications of EnviroLand is teachingpollutant fate and transport in “service” science courses.Students in such classes typically have lowermathematical skills and our teaching team placesconsiderable emphasis on learning the basic physical andchemical processes represented in the model as opposedto “plug and chug” calculations.
Before we introduce the students to EnviroLand weuse several math exercises to familiarize them with thebasic principles of linear versus non-linear relationshipsand basic applications of logarithms. After this, we havethe class as a group create a figure illustrating theparameters of a stream, lake, or aquifer that areimportant in determining the fate and transport of apollutant. Such a diagram for a stream is shown inFigure 1. Next we select the appropriate fate andtransport module and relate each physical or chemicalprocess illustrated by the figure created by the studentsto the relevant portions of the governing equation(shown in Table 1). Again, concepts are emphasized,rather than calculations. Next, we select a fate andtransport model of relevance to events in the news or oneof regional interest and explain the fundamentalconcepts behind the governing equation for that
556 Journal of Geoscience Education, v. 50, n. 5, November, 2002, p. 553-558
scenario. Finally, the example data set for theappropriate EnviroLand module is uploaded. Thestudents are directed to the plot page where they areinstructed to systematically change one variable in theinput data and observe the effect on pollutantconcentration over time and/or distance. As studentsbecome more familiar with the module, they are asked tosummarize the effects of changing each input variable.For example we suggest asking the following, “Doeschanging the parameter (i.e. flow rate, etc.) result in alinear or non-linear dependence with respect to pollutantconcentration?” As a homework assignment ortake-home exam we have the students select one of theother fate and transport modules and create a pollutantscenario (pollutant input, flow rates, observation site,etc.) such as a tanker accident or a leaking landfill andwrite a summary on their findings. This process is alsouseful in upper-level environmental chemistry,geochemistry, and hydrology courses. We have hadremarkable success with these mathematicalapplications in Earth science courses at WhitmanCollege. Students increase their appreciation ofmathematics and modeling principles.
In Environmental Chemistry - Environmentalchemistry is a relatively new discipline in mostdepartments and fate and transport modeling is usuallyavoided due to its complex nature. Nonetheless, fate andtransport modeling is an important part of theenvironment sciences and should be included in astudent’s education. The American Chemical Society(ACS) recommends the use of speciation and fate andtransport models in any environmental chemistry courseseeking ACS approval. Students in these upper-levelcourses are usually mathematically adept and theyquickly become proficient with EnviroLand. In theseclasses, it is best to have the students read thebackground section on the module of interest beforeusing it in class. These more advanced students quicklylearn the concepts of modeling and linear and non-linearrelationships. A challenging exercise for these studentsis to ask “What model assumptions are the most likely tobe suspect or unrealistic?” and “How would you modifythe model to account for other physical or chemicalprocesses?”
In Hydrogeology - Another use of EnviroLand is inteaching hydrogeology to undergraduate students whohave not had advanced mathematics such as differentialequations or numerical analysis. Most of these coursesare taught using “canned” software, by creatingspreadsheets, or by the old fashioned method of “plugand chug”. The modules contained in EnviroLand canbe used with any of these methods to check the students’answers to homework problems, either as the studentswork through the problems or as a key for the instructor.
CLASSROOM ASSESSMENT ANDCONCLUSIONS
We have successfully used EnviroLand in a variety ofinstructional settings. Although we were initiallycautious in our non-major courses, we found thestudents to be very receptive to EnviroLand’s use. In ouropinion, strudent performance was far superior to thatobserved when traditional teaching methods were used.Performance on take-home assignments and exams forstudents using EnviroLand far surpassed ourexpectations and many students actually received extracredit for their efforts. In environmental chemistry andhydrology classes, students who previously had noformal training or coursework in engineering orhigher-level mathematics, quickly acquired thenecessary skills to complete complicated modelingassignments using EnviroLand. More importantly, thestudents understood the chemical and physicalprocesses governing transport and how these processesare represented in mathematical models. Although wehave not preformed a scientific assessment ofcomputer-assisted instruction, we strongly believe thatthese tools enhance the students’ educational experience.For many students, the software application simplyillustrates the concepts of modeling; for others a moredetailed understanding of modeling is acquired.However, programs such as EnviroLand are not meantto nor should they be used to replace upper-levelmodeling courses that rely on differential equations andnumerical analysis.
ACKNOWLEDGEMENTS
Funding for the development of EnviroLand was madeavailable from the Hartwick College Board of Trustees,the Culpeper Foundation, and the Camille and HenryDreyfus Foundation, Inc.
REFERENCES CITED
Edwards, D.J., Bryon, D., and Sowerbutts, B., 1996,Recent Advances in the Development and Use ofCourseware within Earth Science Teaching, Journalof Geoscience Education, v. 44, p. 309-314.
de Wet, A.P., 1994, Integrating Field Observations withPhysical and Chemical Models in an IntroductoryEnvironmental-Geology Course, Journal of Geo-science Education, v. 42, p. 264-269.
Werner, A. and Roof, S.R., 1994, Using Darcy Flow Tubesto Teach Concepts of Ground-Water Geology,Journal of Geoscience Education, v.42, p.220-227.
Matisoff, G., 1995, Models of Wind-Driven andThermohaline Ocean Circulation, Journal of Geo-science Education, v. 43, p. 133-138.
Lee, M.K., 1998, Hands-On Laboratory Exercises for anUndergraduate Hydrology Course, Journal ofGeoscience Education, v.46, p. 433-438.
Dunnivant et al. - Teaching Pollutant Fate and Transport Concepts 557
Berger, W.H., 1997, Experimenting with Ice-Age Cyclesin a Spreadsheet, Journal of Geoscience Education, v.45, p. 428-439.
Saini-Eidukat, B., 1998, A WWW and Spreadsheet-BasedExercise in Flood-Frequency Analysis, Journal ofGeoscience Education, v. 46, p. 154-156.
Rose, S.E., 1997, A Spreadsheet Approach to theHydrological Cycle, Journal of GeoscienceEducation, v. 45, p. 369-372.
Baker, S.P., Benson, M.A., Palmes, S.L., and Huntoon,J.E., 1995, Numerical Simulation of SedimentaryBasin Formation with Simple Examples forUpper-Division Undergraduates in Technoics orProcess-Sedimentology Courses, Journal ofGeoscience Education, v. 43, p. 230-241.
Barrows, L.J. and Paul, K.M., 1998, A Finite-ElementModeling Approach to Gravitational Tectonic Stressand Earthquakes, Journal of Geoscience Education,v. 46, p. 7-23.
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Bice, D.M., 2001, Using STELLA Models to Explore theDynamics of Earth Systems: Experimenting withEarth’s Climate System using a Simple ComputerModel, Journal of Geoscience Education, v. 49, p.170-181.
Busse, P.L., 1997, Computer Plotting of a Contour Profileby Precollege Students Using NIH Image, Journal ofGeoscience Education, v. 45, p. 150-152.
Hudak, P.F., 1996, Hydrology Lessons and Exercises forIntroductory Physical-Geology Students, Journal ofGeoscience Education, v. 44, p. 315-316.
Hudak, P.F., 1998, Visualizing Ground-Water Fields andContaminant Plumes in an UndergraduateHydrogeology Course, Journal of GeoscienceEducation, v. 46, -. 132-136.
Murray, K.S. and Yavine, O., 1998, Computer-AssistedMineral Identification for Introductory GeologyCourses, Journal of Geoscience Education, v. 46, p.178-181.
Kallio, L.H. and Peltoniemi, M.P., 1995, A ComputerProgram for Learning Basic Refraction Seismology,Journal of Geoscience Education, v. 43, p.11-18.
Gould, C.F. and Whitfo:rd, D.J., 2000, Computer-AidedVisualization and Animation of Ocean WaveDynamics, Journal of Geoscience Education, v. 48, p.267-272.
Renshaw, C.E., Taylor, H.A., and Reynolds, C.H., 1998,Impact of Computer-Assisted Instruction inHydrogeology on Critical-Thinking Skills, Journal ofGeoscience Education, v. 46, p. 274-279.
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