User's guide of Proceessing Modflow 5.0

236 Processing Modflow
6. Click on OK to exit the Add New Particles dialog box.
7. Using a similar procedure add particles around Well 2 and Well 3. Make each of these a
different color (say Green and Black).
8. To display the hydraulic heads and a transverse and longitudinal cross section open the
Environment Options dialog box by Options < Environment…
9. Click the Contours tab, check the Visible box and click on the Restore Defaults button to
get standard settings.
10. Click the Cross Sections tab, check the Visible and Show grid boxes and set
Exaggeration=25, Projection Row=15 and Projection Column=9.
11. Click on OK to exit the Environment Options dialog box.
The hydraulic head contours for layer 3 and cross sections showing the location of the
particles should appear.
12. To set up the particle tracking parameters, open the Particle Tracking (Time) Properties
dialog box by Options < Particle Tracking (Time). In the Tracking Steps group, change
the (time) unit to years, step length to 10 and maximum number of steps to 200.
13. Click OK to exit the Particle Tracking (Time) Properties dialog box.
14. Start the backward particle tracking by Run < Backward.
You can easily see that the flowlines intersect with the river in numerous places (Fig. 6.12).
15. You can produce a plot of the steady state hydraulic heads of Layer 3 and the flowlines by
File < Save Plot As…
< To run forward particle tracking
We will now introduce a contaminant source upstream of Well 2 and see how far the
contamination moves through the steady state flow field after 75, 100 and 125 years.
1. Since the contamination is a surface source we need to place the particles in layer 1, if you
aren*t already in Layer 1 change to it by using the Page Up (PgUp) key.
2. To place the particles on the ground surface, drag a box around the cell [6, 5, 1].
3. In the Cell Faces tab of the Add New Particles dialog box you will notice that the graphic
defines the various faces of an individual cell, since the contamination is a surface source
we only want to place particles on cell face 5.
4. Click the Particles tab and set the number of particles on Face 5 to NI=4 and NJ=4 and set
NI and NJ on all the other faces to 0.
5. Click OK to leave the Add New Particles dialog box.
6. Open the Particle Tracking (Time) Properties dialog box by Options < Particle
Tracking (Time)...
7. In the Tracking Steps group, change the (time) unit to years, step length to 1 and
6.1.2 Tutorial 2 - Confined and Unconfined Aquifer System with River