CE En 547 - Midterm Exam #2 KEY

Fall Semester 2017

Page 1
[Page 2]
Page 3
Page 4
Page 5
Page 6

Multiple Choice

(1.5 pt each)

2. (gms) Assume we are modeling the interaction between a lake and an aquifer using the general head package. The lake is modeled using a polygon in the map module of GMS. What conductance value would be assigned to the polygon representing the lake?

a. The total conductance for the lake.
   
b. Conductance per unit length of the arcs around the boundary of the lake.
   
c. Conductance per unit area of the lake.
   
d. None of the above.

3. (modflow) Assume we are modeling a stream using the River Package in MODFLOW. The stream is modeled using an arc in the map module of GMS. What conductance value would be assigned to the arc representing the river?

a. The total conductance for the river.
   
b. The average conductance for a typical cell size.
   
c. Conductance per unit length of the river.
   
d. None of the above.

4. (modflow) What does the term head overshoot mean?

a. Having too many specified head boundary conditions in the model, thus overconstraining the solution.
   
b. During the iteration process, the MODFLOW solver moves the head too low and causes the cell to artificially go dry.
   
c. Applying fixed head boundary conditions at points corresponding to head values obtained from observation wells
   
d. You are aiming at someone with your gun and you end up shooting over their head.

5. (gms) The units for the value of conductance assigned to polygons in the GMS Map Module for stress packages (River, Drain, General Head, etc.) associated with MODFLOW is:

a. [L]/[T^2]
   
b. [L]/[T]
   
c. [L^2]/[T]
   
d. [1]/[T]
   
e. None of the above

6. (calibration) Suppose you are trying to calibrate a groundwater model and your simulated heads are quite a bit lower than your observed heads. Which of the following would be an effective strategy to raise the simulated heads to get a better match?

a. Increase K and increase recharge
   
b. Increase K and decrease recharge
   
c. Decrease K and increase recharge
   
d. Decrease K and decrease recharge

7. (calibration) Which of the following equations corresponds to the ME error norm?

a.
   
b.
   
c.
   
d. None of the above.