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**Multiple Choice**

(1 pt each)

2. (transient) The **specific storage** is defined as:

a. The change in water stored in a unit volume of water due to a unit increase in head. b. A unit change in water stored in an aquifer due to a unit increase in head. c. The change in water stored in a unit volume of aquifer due to a unit decline in head. d. The change in water stored in an aquifer due to a unit decline in head.

3. (modflow) Which of the following is not required for a **river cell** in MODFLOW:

a. Stage in the river b. Elevation of the top of the river bed sediments c. Elevation of the bottom of the river bed sediments d. Conductance of the river bed sediments

4. (head-darcy) Which of the following statements is **true**?

a. The Darcian velocity is equal to the seepage velocity multiplied by the effective porosity. b. The seepage velocity is equal to the Darcian velocity multiplied by the effective porosity. c. The Darcian velocity is equal to the seepage velocity divided by the effective porosity. d. The effective porosity is equal to the seepage velocity divided by the Darcian velocity.

5. (bc) A **no-flow** boundary corresponding to a hypothetical line where the water on both sides of the line flows directly away from the line is called a

a. imaginary barrier boundary b. flowline no-flow boundary c. groundwater divide d. general head boundary e. none of the above

6. (modflow) Which of the following packages is a **head-dependent** boundary condition?

a. Drain b. Well c. Recharge d. Horizontal Flow Barrier e. All of the above

7. (head-darcy) **Total head** at a particular point in an aquifer is defined as:

a. The height to which water would rise in a piezometer inserted at the point, measured relative to the point. b. The elevation of the point relative to a datum. c. The elevation to which water would rise in a piezometer inserted at the point, measured relative to a datum. d. The elevation head minus the pressure head. e. none of the above

8. (modflow) **MODFLOW** is developed by:

a. The Environmental Protection Agency b. The Department of Energy c. The United States Geological Survey d. The U.S. Army Engineering Research and Development Center in Vicksburg, Mississippi

9. (goveq) The storage term **Ss** represents the volume of water lost from a saturated unit volume of an aquifer due to a unit decline in head. Which of the following is NOT one of the processes that causes water to be expelled from the aquifer as the total head drops?

a. Compression of the soil matrix due to an increase in effective stress. b. A change in the aquifer elasticity c. Expansion of the pore water as the pore water pressure is reduced. d. All of the above contribute to the expulsion of the water.

10. (modflow) Which of the following curves best represents the relationship between the drain-aquifer flow rate (Q) and the computed head (H) for a **drain** object in MODFLOW? The head values increase from left to right.

a. b. c. d.

11. (modflow) Which of the following MODFLOW packages does not require a **conductance value** as part of the input?

a. Stream-Aquifer Interaction b. Drain c. General Head d. Changing Head (CHD) e. All of the above require a conductance value

12. (calibration) Which of the following three calibration error norms will always have the **smallest** value?

a. Mean error (ME) b. Mean Absolute Error (MAE) c. Root Mean Squared Error (RMS)

13. (transient) **Specific yield** is defined as:

a. The volume of water lost from a unit area of an unconfined aquifer due to a unit decline in head. b. The volume of water lost from a unit area of a confined aquifer due to a unit decline in head. c. The volume of water lost from a unit volume of a saturated aquifer due to a unit decline in head. d. The volume of water lost from a unit area of a partially saturated aquifer due to a unit decline in head. e. None of the above

14. (calibration) Suppose you are trying to calibrate a groundwater model and your simulated heads are quite a bit **higher** than your observed heads. Which of the following would be an effective strategy to lower 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

15. (goveq) For the governing equation:

which of the following **conditions** apply?

a. isotropic b. anisotropic c. 2D d. 3D e. steady state

16. (goveq) For the following governing equation:

which of the following **conditions** apply?

a. anisotropic b. steady state c. 3D d. sources and sinks e. transient