Exercise 6

How does the scale of hydraulic conductivity heterogeneity influence advective transport in aquifers? The information below provides a tool for you to evaluate this.

The Particle Flow software (Hsieh, 2001) can be used to explore the influence of hydraulic conductivity heterogeneity on the movement of particles in groundwater. You can download and install a Windows version of the software or use the online version.

Once you have the Windows software installed, launch the software by double clicking on the file pflow.exe and follow the straight-forward, step-by-step directions in the document that is provided with the software (that is, ofr01-286.pdf). Or, if you use the online version, read the website materials about the software and click on the ParticleFlow button to launch it.

Using the software, as described below for Model 1 and Model 2 below, set up two models of the same total area, but with different cell sizes. In both models choose to randomize the properties, solve for heads (notice the similarities), under flow choose particle movement with particles spaced 10 m apart and input to view 100 days of travel time in 1 second of real time, then draw a shape to indicate where particles will be added and click on the flow field to start the particles moving. These steps are described in detail where you access the software.

  • Model 1: use a cell size of 10 m with 100 columns and 25 rows, and a gradient of 0.002. Place particles on upgradient side and release.
  • Model 2: use a cell size of 50 m with 20 columns and 5 rows, and a gradient of 0.002. Place particles on upgradient side and release.

Rerun the simulation as many times as you want with different particle releases. Remember the differences are due to the size of zones with differing hydraulic conductivity. The zones are much larger in Model 2.

You may also wish to create your own patterns of heterogeneity. The instructions for the software will show you how to do that.

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Introduction to Karst Aquifers Copyright © 2022 by Eve L. Kuniansky, Charles J. Taylor, and Frederick Paillet. All Rights Reserved.