MODFLOW Case Study - Dealing with Dry Cells

This exercise involves a variation of the Fremont River model. The model is the same as before, except that the bottom elevations have been changed from 250 m to 280 m.

1) Download and unzip the startfiles.zip file.

2) Save and run the model. Read the solution.

a) What has happened to the wells?

b) Why did this happen?

3) Try fixing the problem by adjusting the acceleration parameter in the solver.

4) Try using another solver.

5) Try increasing the K value in the cells containing the wells.

a) Why did this work?

b) Is this a legitimate (defensible) approach?

c) Can you think of any other strategies that may solve the problem?

6) Change the K values in the cells back to the original values and then switch to MODFLOW-NWT and turn on the Newton solver.

a) Did the cells go dry?

b) Look at the flow budget. Notice anything odd?