User's guide of Proceessing Modflow 5.0

230 Processing Modflow
2. Ensure that for layer 1 the type is set to 1:unconfined. Ensure that Layer 2 and 3 are set to
3:confined/unconfined.
3. Click OK to exit the Layer Options dialog box.
Flow boundaries
< To specify the IBOUND data
1. Select Grid < Boundary Condition < IBOUND (Modflow)
2. Set fixed-head boundaries (IBOUND = -1) in layer 1 and layer 3 (remember the Page Up
and Page Down keys to switch between layers) at the west and east boundaries where the
river enters and leaves the model area. Note that the horizontal flow component in the
second layer (silty layer) is negligible, so we do not need to specify fixed-head cells to this
layer.
3. Set no flow boundaries in all layers in the areas defined by the Granite and South Granite
Hills. The boundaries in layers 1 and 3 should look like those in Fig. 6.9. The boundaries in
the layer 2 should look like those in Fig. 6.10.
4. Leave the Data Editor by File < Leave Editor < Yes
Aquifer geometry
The top of each aquifer slopes gradually from west to east. To save you enterring this data, the
top elevation of each aquifer has been saved as a data file.
< To specify the top elevation of each aquifer
1. Select Grid < Top of Layers (TOP).
2. Import the file \pm5\examples\tutorials\tutorial2\aq1top.dat as the elevation of the top of
aquifer 1 using Value < Matrix < Load... etc.
3. Switch to Layer 2 by pressing the Page Down (PgDn) key.
4. Import the file \pm5\examples\tutorials\tutorial2\aq2top.dat as the elevation of the top of
aquifer 2.
5. Switch to Layer 3 by pressing the Page Down (PgDn) key.
6. Import the file \pm5\examples\tutorials\tutorial2\aq3top.dat as the elevation of the top of
aquifer 2.
7. Leave the Data Editor by File < Leave Editor < Yes
6.1.2 Tutorial 2 - Confined and Unconfined Aquifer System with River