Notice the gwv.pdf file that you can refer to for directions on how to use GWV.

It will be most useful if you follow along with your copy of GWV on your computer.

Open GWV on your computer

Select File>New
or
Click on the New Document button

Set global parameters to initialize the model input.

# rows 30
# columns 30
x spacing 330ft
y spacing 220ft
#layers 3
bottom elevation 0.
top elevation 150.
# stress periods 1
change Kz to 10ft/d
change recharge rate to 0.002 ft/d



You could set other global values at this time as well. Look over the screen to get an overview of global values that can be set here.

Click OK

Select View>Full>Screen
Adjust your window size as desired. Your grid should look like this



Change the font size for the row and columns

Select Grid>Options>Font

Set the font to 16

Select OK

Import a base map by

Selecting File->Map->GWVistas

Choose the map called t2.map in the GWV tutorial directory or get it here t2.map

Select View->Full->Screen to fit everything back in the GWV window

GWV has four modes

Analytic Elements

define and alter grid-independent boundary conditions

Grid

add, delete, and move rows, columns, and layers

Boundary condition

edit grid-dependent boundary

Property zones

assign physical properties (e.g., hydraulic conductivity) to each cell

You can select these from the Edit menu where the active option is checked
      or
use the button on the tool bar
      Buttons on the right side of the toolbar change for each mode

For Boundary conditions options include
  insert and delete windows, insert polyline or polygon, and options
For Properties options include
  default zone, zone window, digitize polygon, transpose zones, and zone database
For Grid editting options include
  delete rows, insert rows, delete columns, insert columns, and grid options
For Analytical Elements options include
  particale trace, line boundary, circle boundary, target, well

To insert, move, and delete rows, columns, and layers, you must be in “grid” mode.

The cursor behaves differently in grid mode.

When you are close to a row or column grid line, the cursor changes shape to either a left-right or up-down arrow.

Pressing the left mouse button when this cursor appears allows you to slide the row or column line to a new position.

You may insert or delete rows, columns, and layers using the menu commands.

In Grid mode the right mouse button inserts a row or column into the model or deletes the nearest row or column, depending on the current grid operation (shown at the bottom of the Grid menu and as a depressed button).

Add two rows and two columns to the model.

Enter Grid mode

Split row 15 into two new rows by placing the cursor anywhere within row 15 and click the right mouse button

Repeat this procedure for the next row to the south (Row 16 of the original model)

When you insert a row or column, the default behavior is to split the current cell in half.

You may change the way rows/columns are inserted by selecting Grid-> Options.

Split columns 14 and 15 just like rows 15 and 16 above

     

Select Boundary Conditions

Add a column of constant heads along the left edge of the model in layer 1.

To set a large number of boundary conditions,

Select BCs->Insert->Window

The cursor will change shape and appear like a mini-finite-difference grid

Move the cursor to the upper left corner of the model (row 1, column 1) and press the left mouse button.

Hold the mouse button down and move the cursor to the lower left corner (row 30, column 1).

Release the mouse button and a dialog appears to confirm the coordinates of the window that you just created, press OK to accept these coordinates.

A constant head dialog appears.

Change this value of constant head to 150 ft.

Notice that the boundary condition is steady-state. This means that the boundary cells will be active during the entire simulation. In this version of MODFLOW, constant heads are active for the entire simulation and cannot be changed.

The constant head cells will appear blue

Move to layer 3 of the model.

The easiest way to change layers is by clicking the “+” button next to “Layer” on the 3D cube (called the Reference Cube) that is on the left side of the screen.

Select BCs->Well

Move the cursor to row 16, column 15 and click the left mouse button.

You will notice that as you move the cursor on the screen, the status bar at the bottom of the screen updates the current row and column.

When you are at row 16, column 15 the status bar should read “R:16 C:15”.

After clicking the mouse button, a well edit dialog will appear.

Enter a flow rate of -30000 ft³/d

GWV assumes that units of length and time are consistent for all parameters. In this example, all length units are in feet and all time units in days.

Add another well at row 8, column 16. This time, enter a flow rate of -40000.

     

The model definition is complete, so move on to define MODFLOW specific features, create MODFLOW files, and execute MODFLOW
MODFLOW specific settings, file creation and execution

Post Processing
View results of MODFLOW execution

Calibration
GWV calibration features

Editing a model in GWV
GWV editing features

Take some time to visit each MODFLOW package in this GWV example problem. As you look at the data in GWV, find the MODFLOW file for that package on your disk and view it in a text editor. If there are any items that you do not understand, please ask me about them by e-mail.

There are a number of GWV assumptions and constructs that influence how you build your model
Read GV Concepts on page 29 of the manual.