LINDANE IN LILLIPUT: TEACHING HYDROGEOLOGY WITH SANDBOX MODELS

Our responsibility as educators is to provide hydrogeology students with the most realistic training possible. Unfortunately, time and budgetary constraints rarely permit students to manage a real groundwater contamination case from SI to clean closure in a semester. An alternate approach is to use bench-scale groundwater flow systems (“sandbox models”) to simulate the tasks and challenges budding hydrogeologists may face if they choose careers in the environmental industry.

Three sandbox models (45x60x15 cm) were constructed to test their pedagogic merit in an undergraduate hydrogeology course of 9 students. Models employed various boundary conditions, including leaking pipelines, streams, lakes, and storm drains. One model included a confined “fractured limestone” aquifer composed of Styrofoam bricks, another a homogeneous sand aquifer, and a third a “layer cake” of sand and clay. Models were landscaped with roads, buildings, and utilities. Each model was “contaminated” at an undisclosed location by a 1 g/L solution of NaCl. Students were grouped into 3 consulting firms and asked to write weekly letter reports to an EPA regulator (the professor). Tasks included producing topographic site maps, drilling and installing wells, constructing well logs from core, producing potentiometric surface and flow maps, conducting well hydraulic tests, and generating contaminant plume maps.

Students considered the sandbox models to be one of the most valuable learning tools of the course. On a scale from 0 to 5 (5 being highest), student self-confidence in 16 skill categories increased from a mean of 0.91 (+/- 0.38) before the course to 4.3 (+/- 0.37) after working with the models. Probing miniature aquifers with soda straws will never replace the value of drilling real monitoring wells. However, sandbox models mixed with a little imagination and creativity can bolster skills and confidence as students prepare their careers as hydrogeologists.