The MODFLOW 6 model differs from the MODFLOW-2005 version of the model by having a DISV grid. The DISV grid has a refined area around the extraction wells in the southern half of the model. The Ghost Node Correction package is used with the explicit option; the implicit option makes the model unstable. To use PEST with the model we will perform the following tasks.
•Make a few small but important changes to the model.
•Activate PEST.
•Define parameters to use in the model.
•Define parameter groups and assign parameters to them.
•Apply parameters to data sets.
•If desired, define pilot points.
•Apply parameters to boundary conditions.
•Define observations.
•Define observation groups.
•Assign observations to observation groups.
•Define prior information equations for Tikhonov regularization.
•Run PEST.
•Visualize weighted residuals.
•Visualize the modified model input.
The estimated time required to complete this exercise is 1 to 3 hours but the time required can be greatly affected by the speed at which the model runs on the computer used for the exercise.
